MLS 404 Lecture Notes (Med. Lab. Micro. 1).docx

**BINGHAM UNIVERSITY** **FACULTY OF HEALTH SCIENCES** **DEPARTMENT OF MEDICAL LABORATORY SCIENCE** **400 Level Second Semester 2023/2024 Session** Course Title: Medical Laboratory Microbiology 1 Course Code: MLS 404 (4 Units) **Introduction** Epidemiology is a branch of medicine which is conc...

**BINGHAM UNIVERSITY** **FACULTY OF HEALTH SCIENCES** **DEPARTMENT OF MEDICAL LABORATORY SCIENCE** **400 Level Second Semester 2023/2024 Session** Course Title: Medical Laboratory Microbiology 1 Course Code: MLS 404 (4 Units) **Introduction** Epidemiology is a branch of medicine which is concerned with the occurrence and distribution of disease, including infectious diseases and non infectious diseases such as cancer. In epidemiological studies, the members of a population are counted and described in terms of such variables as race, sex, Age, social class, occupation and marital status; then the incidence and prevalence of the disease of interest are determined. These observations may be repeated at regular intervals in order to detect changes over time. The result is a statistical record that may reveal links between particular variables and distribution of the disease. In comparative epidemiological studies, two or more groups are chosen. For example, in a study of the link between commercial sex workers and cervical cancer, one group may consist of commercial sex workers and non-commercial sex workers (responsible house wives). The proportion with cancer in each group is calculated. or on the other hand in the study link between smoking and lung cancer, one group may consist of smokers and the other of nonsmokers. Studies of epidemiology of infectious diseases include evaluation of the factors leading to infection by an organism, factors affecting the transmission of an organism and those associated with clinically recognisable disease among those who are infected. Other concepts include the following: - The incubation period: diseases caused by either an infectious agent or non infectious agent such as a toxin or carcinogen have an intrinsic incubation period after contact with the agent before disease occurs. - Resistance: some individuals may have immunity or resistance to infection on a biologic basis such as from previous infection, immunization or because of host genetics and remain uninfected after exposure. It is the responsibility of the microbiologist to be primarily interested in the characteristics of an organism and may try to determine the following: - How can the organism be isolated? - How can an infection be diagnosed or confirmed in the laboratory? - Is it possible to prepare a vaccine or treat an infection with an antibiotic? - What are the essential growth requirements of the organism? Epidemiology is based on two fundamental tenets. The first is the observation that human disease does not occur at random i.e there must be a pattern. The second is that there are casual, and possibly preventable factors that influence the development of disease. Epidemiologic studies of infectious diseases try to evaluate the contribution of different factors in the transmission and acquisition of infections and those factors favoring endemic transmission and epidemics. Epidemiologic studies can also be used to evaluate the effects of interventions. THE EPIDEMIOLOGICAL TRIANGLE How to investigate the cause of disease outbreak Triangle The epidemiological triangle is used to describe the relationship between the host (I.e the diseased person) and the agent (i.e the infecting bacteria, virus, parasite or fungi) and the environment (i.e the setting in which transmission occur). The epidemiological triangle for some diseases , the interaction may be described by the interaction between the host, environment and agent. For either diseases, the interaction must include a second triangle to describe the extrinsic life cycle of the agent outside of the human host. EPIDEMIOLOGIC STUDY: Prior to investigating an epidemiologic study, it is useful to consider the following questions: 1. Who is to be studied(sampling)? 2. What data are going to be collected (data collection)? 3. How are these data group to be analysed (analysis)? these three questions influence the design of an epidemiologic study [Disease surveillance ] The centres for disease control and prevention (CDC) in 1986 defined epidemiologic surveillance as the ongoing systematic collection, analysis and interpretation of health data essential to the planning, implementation and evaluation of public health practice, closely integrated with the timely dissemination of these date to those who need to know. The final link in the surveillance chain is the application of these data to prevent and control. A surveillance system includes a functional capacity for data collection, analysis, and dissemination link to public health performances for the purpose of improving the health of the population and preventing disease. Therefore, surveillance needs to be selective, planned and tailored to meet a specific goal in the prevention of disease [Steps needed for a successful disease surveillance] 1. Details of the person involved, their sex/gender, age etc 2. When it occurred (time and date) 3. Where and how the disease occurred 4. Signs and symptoms of the disease 5. Mode of transmission of the disease 6. Diagnosis of the disease 7. Result/report 8. Prevention and control(recommendations) [Importance of disease surveillance ] 1. Epidemiologic surveillance is important for the interpretation of health data 2. It is essential for planning of public health practice 3. It is very important for preventive measures to be successful 4. It is important for the evaluation of public health practices 5. It is very vital for the control of disease outbreak 6. It helps in the dissemination of data to those who need them 7. It is very important to improve public health programmes for the purpose of improving the health of the population 8. It is very important to reduce direct and indirect transmission of known illnesses 9. It is important to identify new mechanisms of transmission of known illnesses 10. It is important to identify new mechanisms of transmission of known illnesses 11. To satisfy legal and international obligations [Emergence of Diseases ] Emergence of Diseases is referred to some diseases that spring up or are being spread or distributed as a result of human activities which affects the environments and also human being either directly or indirectly, thus help or aids in the spreading of diseases among the people which ordinarily can be controlled **Examples of emergence of disease;** 1. Some customs/ traditions that allow the transfer of a late brother\'s wife to another brother with the hope of family continuity without the retest for HIV and other sexually transmitted diseases 2. In some cultural practices people use same spoon or calabash to take food at the same time rotationally or join their mouth to one calabash when drinking local alcohol with the ideology of sharing love, these can lead to transfer of communicable disease such as tuberculosis, ebola etc. 3. In some religious practices, the members of the religion exposed their members to certain parasitic diseases and bacterial infection e.g immersion of people into rivers during baptism may lead to certain parasitic infection such as schistosomiasis, duodenalisis e.t.c 4. Removal of female clitoris by the traditional practices and some cultures 5. The local circumcision without giving antitetanus injection and antibiotics can lead to severe infection and even death [Outbreak epidemiology] Outbreak epidemiology is the study of a disease cluster or epidemic in order to control or prevent further spread of disease in a population. The word epidemic is defined as increase in the number of cases of disease above what is expected, is derived from the Greek word(epi-demos), meaning "thou which is upon the people". This definition also allows us to realise that epidemics are not always caused by infectious agents. Many other hazards such as chemicals or physical conditions, can cause unusually high numbers of cases of disease in a fewer population. Nevertheless, the techniques used to investigate and control outbreak are generally similar, regardless of the etiology of the disease. Today, there are new challenges in the control of infectious diseases. Public health officials and health care providers face the emergence of new diseases and the re-emergence of disease that were no longer thought to be a threat to the publics health.the intentional use of biologicagents or their toxins (e.g anthrax, botulism and small pox) as weapons of bioterrorism has occurred recently in the United States. Changes in the environment due to effects on the ozone layer industrial practices, modern use of fertilisers in agriculture and food processing and changes in human behaviours have increased the risk of disease and spread at which communicable disease can spread e.g easy transportation of foods, goods and human beings. **Morbidity**: it is the state or condition of being diseased. In medical statistics, the morbidity ratio is the proportion of disease people to healthy people in a particular community at a particular time(period) **Mortality**: it is the death rate, which is the number of deaths per 100,000(or 10,000 or 1000) of the population per year. Mortality is often calculated for specific groups. For example, infant mortality ,measures death of live-born infants during the first year of life, standardised mortality allows comparison of the death rate in for example an occupational or socioeconomic group with that for the entire population. Example of waterborne disease- Pseudomonas aeruginosa, mycobacterium marinium, Legionella. Non infectious diseases or non-communicable diseases e.g cancer, heart, renal diseases and strokes [Endemic]- this is referred to a disease or disorder that is constantly present in a particular region or in a specific group of people e.g malaria is endemic in west Africa(Nigeria) [Pandemic:] this is referred to a disease that occurs over a large geographical area and can affect a high proportion of the population; a wide spread endemic. [Sporadic]: scattered, occuring in isolated cases not epidemic- sporadically [Epidemic]: this is referred to a disease that for most of the time is rare in a community but suddenly spreads rapidly to affect a large number of people. E.g an epidemic of new strains of Salmonella typhi [Communicable disease:] this is referred to any disease due to microorganisms or parasites that can be transmitted from one person to another, it is also referred to as a contagious or infectious disease. Food Posoning This is defined as a disease caused by intake of food that is contaminated by harmful substance/ pathogenic microorganisms or toxic Substances produced as a result of their metabolic properties. Example: mycotoxins produced by fungi, Botulism caused by clostridium Shigellosis caused by shigella dysenteries Salmonellosis caused by Salmonella typhi, cholera caused by vibrio cholerae Example of bacteria common in food and water borne diseases are: Vibrio cholerae - which is a common etiologic agent of water and food diseases there by causing cholera Salmonella typhi- common etiologic agent of water and food which cause salmonellosis or typhoid fever Bacillus aureus - which produces bacteria form toxins therefore causing botulism and diarrhea syndrome. Shigella dysenteriae - It is a disease agent in water and food causing dysentery Buccella abortus- Commond FBD- causing brocellotus (undulant fever) causes abortion in a nimals when they drink **THE ROLE OF PUBLIC HEALTH AND ENVIRONMENTAL MICROBIOLOGY** INTRODUCTION The goal of public health is to prevent illness and injury, promote healthy lifestyles, and create environments that support good health. In this research, we will explore the importance of public health in society. - **Public health:** Public health is defined as the science and art of preventing diseases, prolonging life, promoting health and efficiencies through organized community effort. It is concerned with the health of the whole population and the prevention of disease from which it suffers. - **Environmental microbiology:** It is a branch of microbiology that studies the role of micro-organisms in the maintenance of a healthy, quality and sustainable environment. - **Environment** is defined as the circumstances or conditions that surround an organism or group of organisms. The environment includes abiotic factor such as climate, water, minerals, and sunlight as well as biotic factors such as organisms, their products, and effect in a given area. Public health is an essential part of any society. It plays a critical role in disease prevention, promoting healthy lifestyles, environmental health, reducing health disparities, and emergency preparedness. Public health professionals work to improve the health of entire populations and create environments that support good health. By promoting health equity, public health helps ensure that everyone has the opportunity to achieve optimal health. Therefore, investing in public health is critical for the well-being of individuals and communities alike. Investing in public health is a critical aspect of improving the well-being of individuals and communities. Public health interventions and programs have the potential to prevent and control diseases, promote healthy behaviors, and address health inequities. One of the key benefits of investing in public health is the prevention and control of diseases. Public health interventions such as vaccination programs, disease surveillance, and outbreak investigations can help prevent the spread of infectious diseases. By identifying and containing outbreaks early, public health professionals can prevent diseases from spreading throughout communities and causing widespread illness and death. Investing in public health also promotes healthy behaviors that can prevent chronic diseases such as heart disease, diabetes, and cancer. Public health interventions such as education campaigns, community-based programs, and policy changes can encourage people to make healthier choices, such as eating a balanced diet, being physically active, and not smoking. **THE** **ROLES OF PUBLIC HEALTH** 1. **HEALTH PROMOTION:** One of the primary functions of public health is disease prevention. Public health professionals work to prevent the spread of diseases, such as HIV/AIDS, tuberculosis, and influenza. They accomplish this by developing and implementing strategies for immunization, infection control, and education. For example, public health professionals promote immunizations by educating the public on the benefits of vaccines and ensuring that vaccines are accessible to all. Public health also plays a critical role in promoting healthy lifestyles. Public health professionals work to reduce risk factors for chronic diseases, such as heart disease, diabetes, and cancer. They promote healthy behaviors, such as physical activity and healthy eating, and work to create environments that support these behaviors. For example, public health professionals may work with schools to develop healthy meal options and encourage physical activity. Health promotion is a guiding concept involving activities intended to enhance individual and community health well-being. It seeks to increase involvement and control of the individual and the community in their own health. It acts to improve health and social welfare, and to reduce specific determinants of diseases and risk factors that adversely affect the health, well-being, and productive capacities of an individual or society, setting targets based on the size of the problem but also the feasibility of successful interventions, in a cost-effective way. Health promotion is a key element in public health and is applicable in the community, clinics or hospitals, and in all other service settings. Raising awareness and informing people about health and lifestyle factors that might put them at risk requires teaching. The Elements of Health promotion comprises of - Addressing the population as a whole in health related issues, in everyday life as well as people at risk for specific diseases, - Directing action to risk factors or causes of illness or death. - Undertaking activities approach to seek out and remedy risk factors in the community that adversely affect health. - Promoting factors that contribute to a better condition of health of the population. - Initiating actions against health hazards,including communication,education, legislation, fiscal measures, organizational change,community development, and spontaneous local activities - Involving public participation in defining problems,deciding on action - Advocating relevant environmental,health, and social policy - Encouraging health professionals' participation in health education and health policies. 2. **ENVIRONMENTAL HEALTH:** Another essential role of public health, is environmental health. Public health professionals work to identify and address environmental health hazards, such as air pollution, lead poisoning, and contaminated drinking water. They also promote policies and regulations that protect the environment and public health. For example, public health professionals may work with policymakers to develop regulations that reduce air pollution and protect water quality. 3. **PREVENTION OF DISEASE:** Prevention, refers to the goals of medicine that are to promote, to preserve, and to restore health when it is impaired, and to minimize suffering and distress. There are three levels of prevention: - Primary Prevention refers to those activities that are undertaken to prevent the disease and injury from occurring. It works with both the individual and the community. It may be directed at the host, to increase resistance to the agent (such as immunization or cessation of smoking), or may be directed at environmental activities to reduce conditions favorable to the vector for a biological agent, such as mosquito vectors of malaria. - Secondary Prevention is the early diagnosis and management to prevent complications from a disease. It includes steps to isolate cases and treat or immunize contacts to prevent further epidemic outbreaks. - Tertiary Prevention involves activities directed at the host but also at the environment in order to promote rehabilitation, restoration, and maintenance of maximum function after the disease and its complications have stabilized. Providing a wheelchair, special toilet facilities, doors, ramps, and transportation services for paraplegics are often the most vital factors for rehabilitation 4. **HEALTH DISPARITIES:** Public health is also critical for addressing health disparities. Health disparities refer to differences in health outcomes between different groups of people. Public health professionals work to reduce health disparities by promoting health equity. This means that everyone has the opportunity to achieve optimal health, regardless of their race, ethnicity, income, or other factors. For example, public health professionals may work to improve access to healthcare services in underserved communities. 5. **EMERGENCY PREPAREDNESS:** Public health is essential for emergency preparedness. Public health professionals work to prepare for and respond to public health emergencies, such as natural disasters, disease outbreaks, and bioterrorism. They develop emergency response plans, coordinate with other agencies and organizations, and ensure that communities are prepared to respond to emergencies. For example, public health professionals may work with hospitals to develop plans for responding to disease outbreaks. 6. **REHABILITATION:** Rehabilitation,is the process of restoring a person's social identity by repossession of his/her normal roles and functions in society. It involves the restoration and maintenance of a patient's physical, psychological, social, emotional, and vocational abilities. Interventions are directed towards the consequences of disease and injury. The provision of high-quality rehabilitation services in a community should include the following. - Conducting a full assessment of people with disabilities and suitable support systems - Establishing a clear care plan - Providing measures and services to deliver the care plan. 7\. DISEASE CONTROL AND SURVEILLANCE: Disease control and surveillance are critical components of public health microbiology in Nigeria. The country has been plagued by several infectious diseases, including malaria, tuberculosis, and HIV/AIDS, among others. Microbiology plays a significant role in the diagnosis, treatment and prevention of these diseases. However, disease control and surveillance in Nigeria face several challenges. According to a study published in the Global Health Journal, the lack of integration of new approaches, such as the use of Big Data, mobile health approaches, and cutting-edge quantitative methods, makes them unsustainable or unrealistic for most national control programs. The gulf between academia and policymakers remains a significant barrier to their implementation (Buckee et al., 2018). Another study published in the Infectious Diseases of Poverty Journal highlights the need for highly sensitive and specific diagnostic tools to target mass screening of asymptomatic gametocyte reservoirs in low/moderate endemic areas, sub-microscopic parasitaemia, and intensive integrated management of hotspots linked to environmental, climatic, and ecological appropriateness for Anopheles vectors and transmission (Tambo et al., 2014). To improve our disease control and surveillance capabilities as well as reduce the burden of endemic infectious diseases and prepare for emerging epidemic threats, Nigeria must integrate the use of big data, mobile health approaches and cutting-edge quantitative methods to enable early detection of outbreaks, tracking of disease patterns and monitoring of disease trends. There must be a collaboration between academia and policymakers to help bridge the gap between research and policy implementation. We should also gear towards the development of highly sensitive and specific diagnostic tools for early infection detection. To overcome these challenges, it is important for microbiology students to seek internships, engage in practical learning, develop transferable skills, and actively network during their education. Additionally, government and educational institutions can play a role in improving the quality of education, research opportunities, and job market prospects for microbiology graduates. - Preventing epidemics - Protecting the environment, workplace,food and water - Promoting healthy behavior - Monitoring the health status of the population - Mobilizing community action - Responding to disasters - Assuring the quality, accessibility, and accountability of medical care - Reaching to develop new insights and innovative solutions. - Leading the development of sound health policy **Ethical issues and challenges in public health** Public health is usually viewed as a broad social movement, a way of asserting social justice, value and priority to human life. On the other hand, market justice prevents the fair distribution of burdens and benefits among society. The following are challenges and ethical concerns in public health. 1\. Political conservatism and public health -- in this view, politics conserves the broad vision of public health and prefers it to limit into a technical enterprise focusing on controlling communicable diseases and a safety net providing medical care to the indigent. 2\. Collective scope and individualism -- individualistic societies resist the notion of public health's concern for the collective 3\. Economic impacts - public health regulations affects the industries (E.g. tobacco), those paying for the public health benefits may not necessarily be the beneficiaries (E.g. Regulatory actions for worker safety raising costs to consumers), people may not be willing to pay costs for benefits that would accrue in the long future (E.g. measures to limit global warming) and it is easier to calculate current costs incurred for public health than the benefits that would come later. 4\. Promoting public welfare versus individual liberty -- the extent to which governments should restrict individual freedom for the purpose of improving community health ( E.g. AIDS control in Cuba) 5\. Paternalism versus libertarianism -- restrictions on individual behavior for protecting their own health (E.g. enforcing seat belts). libertarianism claims that "the only purpose for which power can be rightfully exercised over any member of a civilized community, against her / his will is if her/his act harms others( E.g. regulate drunk behavior no drinking) 6\. Public health measures and religion/moral -- some public health measures are not acceptable on religious and moral grounds ,(E.g. sex education and distribution of contraceptives and/or condoms to adolescences). 7\. Values and responsibilities - health authorities deciding on values and choices of those they serve (e.g. whether some one should not take the responsibility on behavior causing ill health such as smokers, alcoholics, promiscuous people ), decision on whether to emphasize HIV/AIDS prevention versus ARV therapy in poor countries, the extent of providing access to benefits to research subjects. 8\. Surveillance versus cure -- involves how to deal with sick subjects identified in routine survey/data collection 9\. Dilemmas in cost benefit analysis -- the difficulty of valuing life, and values to be assigned for the rich versus the poor. Environmental microbiology is the study of the composition and physiology of microbial communities in the environment. The environment in this case means the soil, water, air and sediments covering the planet and can also include the animals and plants that inhabit these areas. Environmental microbiology also includes the study of microorganisms that exist in artificial environments such as bioreactors. Molecular biology has revolutionized the study of microorganisms in the environment and improved our understanding of the composition, phylogeny, and physiology of microbial communities. The current molecular toolbox encompasses a range of DNA-based technologies and new methods for the study of RNA and proteins extracted from environmental samples. Currently there is a major emphasis on the application of \"omics\" approaches to determine the identities and functions of microbes inhabiting different environments. Microbial life is amazingly diverse, and microorganisms literally cover the planet. It is estimated that we know fewer than 1% of the microbial species on Earth. Microorganisms can survive in some of the most extreme environments on the planet and some can survive high temperatures, often above 100°C, as found in geysers, black smokers, and oil wells. Some are found in very cold habitats and others in highly salt\|saline, acidic, or alkaline water. An average gram of soil contains approximately one billion (1,000,000,000) microbes representing probably several thousand species. Microorganisms have special impact on the whole biosphere. They are the backbone of ecosystems of the zones where light cannot approach. In such zones, chemosynthetic bacteria are present which provide energy and carbon to the other organisms there. Some microbes are decomposers which have ability to recycle the nutrients. So, microbes have a special role in biogeochemical cycles. Microbes, especially bacteria, are of great importance in the sense that their symbiotic relationship (either positive or negative) have special effects on the ecosystem. Microorganisms are cost effective agents for in-situ remediation of domestic, agricultural and industrial wastes and subsurface pollution in soils, sediments and marine environments. The ability of each microorganism to degrade toxic waste depends on the nature of each contaminant. Since most sites are typically comprised of multiple pollutant types, the most effective approach to microbial biodegradation is to use a mixture of bacterial species/strains, each specific to the degradation of one or more types of contaminants. It is vital to monitor the composition of the indigenous and added bacterial consortium in order to evaluate the activity level of the bacteria, and to permit modifications of the nutrients and other conditions for optimizing the bioremediation process. - Oil Biodegradation Petroleum oil is toxic and pollution of the environment by oil causes major ecological concern. Oil spills of coastal regions and the open sea are poorly containable, and mitigation is difficult, however much of the oil can be eliminated by the hydrocarbon-degrading activities of microbial communities, in particular the hydrocarbonoclastic bacteria (HCB). These organisms can help remediate the ecological damage caused by oil pollution of marine habitats. HCB also have potential biotechnological applications in the areas of bioplastics and biocatalysis. - Degradation of Aromatic Compounds by Acinetobacter Acinetobacter strains isolated from the environment are capable of the degradation of a wide range of aromatic compounds. The predominant route for the final stages of assimilation to central metabolites is through catechol or protocatechuate (3,4-dihydroxybenzoate) and the beta-ketoadipate pathway, and the diversity within the genus lies in the channelling of growth substrates, most of which are natural products of plant origin, into this pathway. - Analysis of Waste Biotreatment Biotreatment, the processing of wastes using living organisms, is an environmentally friendly alternative to other options. Bioreactors have been designed to overcome the various limiting factors of biotreatment processes in highly controlled systems. This versatility in the design of bioreactors allows the treatment of a wide range of wastes under optimized conditions. It is vital to consider various microorganisms and a great number of analyses are often required. - Environmental Genomics of Cyanobacteria The application of molecular biology and genomics to environmental microbiology has led to the discovery of a huge complexity in natural communities of microbes. Diversity surveying, community fingerprinting, and functional interrogation of natural populations have become common, enabled by a battery of molecular and bioinformatics techniques. Recent studies on the ecology of Cyanobacteria have covered many habitats and have demonstrated that cyanobacterial communities tend to be habitat-specific and that much genetic diversity is concealed among morphologically simple types. Molecular, bioinformatics, physiological, and geochemical techniques have combined in the study of natural communities of these bacteria. Environmental microbial research has yielded breakthroughs, including the restoration of fragile soil ecosystems, simultaneous bioremediation during biofuel production, the utilization of soil microorganisms as eco-friendly chemical alternatives, and the exploration of soil microbes as potential sources of industrial products. In Nigeria, microbiology research can play a pivotal role in addressing environmental challenges by developing innovative microbial products and technologies to mitigate pollution and degradation (Krueger et al., 2015). For example, microbiologists can devise microbial solutions to combat environmental pollution caused by plastics. Synthetic polymers, commonly known as plastics, stand out as widespread anthropogenic pollutants in marine, limnic, and terrestrial ecosystems. Microorganisms emerge as the most promising candidates for the eventual bioremediation of environmental plastics. While laboratory studies have reported various effects of microorganisms on many types of polymers, often through enzymatic hydrolysis or oxidation, most common plastics have proven highly resistant even under conditions.favorable for microbial degradation (Krueger et al., 2015). Moreover, microbiology research in Nigeria can contribute to environmental solutions by developing microbial strategies to address the issue of oil spills, a significant environmental problem causing severe damage to the environment and human health. Microbial bioremediation stands out as a promising technology for cleaning up oil spills, where microorganisms can break down hydrocarbons in oil spills into less harmful substances such as carbon dioxide and water(Ezeonu et al., 2012). **ROLES OF ENVIRONMENTAL MICROBIOLOGY IN HUMAN HEALTH** Healthcare Advancement Microbiology research holds significant potential to contribute to healthcare advancement and disease control in Nigeria. The identification of emerging diseases has consistently risen over the years, facilitated by tools like high throughput sequencing, PCR, and MALDI-TOF mass spectrometer, coupled with innovative sampling and culture approaches, thereby transforming clinical microbiology (Fournier & Raoult, 2011; Jones et al., 2008). The Centers for Disease Control and Prevention (CDC) established an office in Nigeria in 2001 to combat HIV, tuberculosis, malaria, and vaccine-preventable diseases, collaborating with the Federal Ministry of Health (FMOH), state ministries, government agencies, and partners to address these health challenges and enhance healthcare in Nigeria (Njidda et al., 2018). Microbiology research plays a pivotal role in enhancing healthcare in Nigeria by innovating new treatments and diagnostic tools for infectious diseases. CDC Nigeria actively supports laboratory systems, risk communication, and vaccine deployment. Through the study of pathogen biology and the development of effective treatments and vaccines, microbiologists contribute to the prevention and control of infectious disease outbreaks (Njidda et al., 2018). Additionally, microbiology research aids in curbing the spread of infectious diseases in Nigeria, as evidenced by CDC Nigeria\'s support for COVID-19 surveillance, epidemiology, emergency response operations, case management, laboratory systems, and vaccine deployment. The CDC also assists in establishing and managing National and state-level Emergency Operation Centers. **ROLE OF ENVIRONMENTAL MICROBIOLOGIST IN WATER QUALITY MONITORING:** Environmental microbiologists monitor water quality by assessing microbial indicators of fecal contamination and pathogens in water sources. Techniques include culturebased methods, molecular assays (e.g., polymerase chain reaction), and immunological assays to detect and quantify microbial contaminants. Monitoring ensures compliance with regulatory standards and protects public health by preventing waterborne disease outbreaks. Respiratory Health Impacts: Airborne microorganisms can cause respiratory infections, allergic reactions, and exacerbate pre-existing respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD). Inhalation of airborne pathogens can lead to pneumonia, bronchitis, sinusitis, and allergic rhinitis, particularly in susceptible individuals with compromised immune or respiratory system. **ROLES OF ENVIRONMENTAL MICROBIOLOGY IN STUDYING SOIL MICROBIAL COMMUNITIES**: Soil microbes play essential roles in nutrient cycling, organic matter decomposition, and plant-microbe interactions crucial for soil fertility and agricultural productivity. Beneficial soil microbes include nitrogen-fixing bacteria (e.g., Rhizobium spp., Azotobacter spp.), mycorrhizal fungi, and plant growth-promoting rhizobacteria (PGPR) that enhance nutrient uptake, disease resistance, and crop yields.Microbes play an important role in soil aggregate formation and soil stability that confer fertility and productivity to soil. Environmental microbiologists study soil microbial communities to understand disease dynamics, develop sustainable pest management strategies, and promote soil health in agriculture. **AGRICULTURAL INNOVATIONS:** Globally, artificial chemicals predominantly govern agricultural practices. The indiscriminate application of chemical pesticides and fertilizers has significant repercussions on soil quality, human health, and the environment (Glick, 2012). With the continuous rise in the world population, there is a pressing need to enhance agricultural productivity while mitigating adverse effects on the environment. Sustainability, as an integrated approach, offers a solution to food production challenges in an environmentally friendly manner (Lal, 2008). Microbiological techniques present a valuable means to enhance crop yields sustainably by improving nutrient acquisition, managing insect pests, and promoting plant growth (Barea et al., 2013). Innovations in microbiology, such as the use of biofertilizers and biopesticides, play a pivotal role in agriculture. The careful selection, application, and screening of stress-tolerant microorganisms are crucial for effectively managing abiotic stress, offering a viable solution to overcome limitations associated with plant production in stress-prone regions. **ROLE OF ENVIRONMENTAL MICROBIOLOGIST IN BIOTECHNOLOGICAL DEVELOPMENT** Biotechnology has transcended numerous challenges, evolving into a scientific discipline that influences various aspects of human activities. It has become a cornerstone in addressing diverse human challenges, with heightened research focus in pharmaceuticals, medicine, biology, agriculture, and environmental sciences. Delving into the intricacies of cellular interiors, particularly in molecular biochemistry and biology, has yielded valuable contributions, such as new drugs and chemicals, proving beneficial in addressing complex health issues like cancer, hypertension, and heart diseases. The traditional reliance on animal cells to produce hormones, growth factors, and insulins has shifted to utilizingfermentation processes involving yeasts and bacteria (Walsh, 2005). Tissue cultures are now the source of monoclonal antibodies, contributing to the expanding array of biotechnological drugs that have achieved substantial commercial success, making them more accessible and affordable.Beyond pharmaceutical applications, biotechnology extends into microbiological realms, presenting opportunities for the production of biopesticides, biofertilizers, environmental controls, and more. Microbiologists play a role in harnessing these advancements, delving deeper into the molecular intricacies of cells and unlocking the vast potential of microorganisms to sustain human survival on Earth. **Data Management and Artificial Intelligence Systems:** Efficient data management is pivotal for the progress of microbiology in Nigeria. The proper handling and organization of data resulting from microbial research empower scientists to derive meaningful insights, fostering a deeper understanding of microbial ecosystems. This encompasses databases containing crucial information on microbial diversity, drug resistance patterns, and epidemiological data. The development of robust data management systems holds the potential to amplify collaboration among researchers, streamline infectious disease tracking, and bolster evidencebased decision-making in public health. The integration of artificial intelligence presents promising avenues for microbiology in Nigeria. AI applications,including machine learning algorithms, exhibit the capacity to swiftly analyze extensive datasets and discern patterns that may pose challenges for conventional methods. In the realm of microbial genomics, AI proves invaluable by aiding in the prediction of antimicrobial resistance, the identification of potential pathogens, and the analysis of intricate interactions within microbial communities. This acceleration of the research process contributes significantly to more effective disease management strategies. Additionally, AI\'s capacity to analyze diverse data sources, encompassing clinical records and environmental factors, enhances disease surveillance, enabling the prediction and mitigation of disease outbreaks in Nigeria and allowing for proactive public health measures. Moreover, AI contributes to personalized treatment approaches by accounting for individual variations in microbial responses. This approach leads to more precise and effective treatment strategies for patients in Nigeria, acknowledging the diversity of microbial strains and patient demographics. In the agricultural sector, AI optimizes soil microbial management, predicts crop diseases, and enhances crop yield---a particularly relevant application in Nigeria, where agriculture holds substantial economic significance. AI also plays a role in monitoring and managing environmental microbiota, contributing to strategies for pollution control and sustainable environmental practices. However, challenges such as data privacy, ethical considerations, and the necessity for a skilled workforce in both data management and AI implementation necessitate attention. Collaborative endeavors involving microbiologists, data scientists, and policymakers are imperative to fully leverage the potential of data management and AI in advancing microbiology in Nigeria. **HARMFUL ROLES OF MICROBES IN THE ENVIRONMENT** 1\. Water borne Pathogens: Waterborne pathogens are microorganisms that contaminate water sources and pose risks to human health when ingested or contacted. Examples include bacteria (e.g., Escherichia coli, Salmonella spp.), viruses (e.g., norovirus, hepatitis A virus), protozoa (e.g., Giardia lamblia, Cryptosporidium spp.), and helminths (e.g., Schistosoma spp.). These pathogens can cause diseases such as gastroenteritis, diarrhea, hepatitis, and parasitic infections. **[BACTERIA]** - Campylobacter:Bacteria of the genus Campylobacter are members of the family Spirillaceae. Campylobacteriosis occurs most frequently in the summer months and the most commonly isolated species is Campylobacter jejuni. The organism can be carried asymptomatically by cattle, sheep, poultry and other birds,and is also isolated from natural waters. Campylobacter species can survive in water for some days but are highly susceptible to chlorination or ultra violet disinfection at the doses typically used in water treatment and should, therefore, not be a risk in treated drinking water, unless it is subject to significant post treatment contamination. - E.coli: Some strains of E. coli can cause serious diarrhoeal disease. Several classes of diarrhoeagenic E. coli are now recognised, which are defined by the possession of distinct virulence factors. The most important of these are the Vero-cytotoxin-producing E. coli (VTEC), in particular VTEC of serogroup O157, but other E. coli serogroups may contain VTEC members. Typical symptoms of people infected with E. coli O157 range from mild diarrhoea, fever and vomiting to severe, bloody diarrhoea and painful abdominal cramps. In 10 - 15 % of cases, a conditionknown as haemolytic uraemic syndrone which can result in kidney failure. Individuals of all ages can be affected but children up to ten years old and the elderly are most at risk. The infectious dose for E. coli O157 is relatively low compared with other bacterial causes of gastro-enteritis, perhaps as low as 10 organisms. - Salmonella: Species of Salmonella are members of the family Enterobacteriaceae and are the causative agents of typhoid and paratyphoid fever, and milder forms of gastro-enteritis. The enteric fevers (typhoid, caused by Salmonella typhi, and paratyphoid, caused by Salmonella paratyphi) remain important contributors to water-borne disease world-wide, although nowadays very rarely in developed countries. Salmonellae can be subdivided into more than 2000 serotypes. Salmonella typhi and Salmonella paratyphi are only associated with humans but the other salmonellae are found commonly in the faeces of animals and agricultural livestock, and have been found in poultry, eggs and meat products. Food-borne contamination is the major route of infection for these bacteria, but transmission can occur by water contaminated with faecal material. Survival in surface water is limited to hours or days, depending on the amount of contamination and the water temperature. Species of Salmonella are susceptible to normal methods of disinfection used in the water industry. E. coli is an adequate indicator for the presence and survival of Salmonella in water. - Shigella: Species of Shigella are members of the family Enterobacteriaceae and cause bacillary dysentery (shigellosis) in humans. The Shigella group is divided into four main sub-groups differentiated by biochemical and serological tests. Shigella dysenteriae, Shigella sonnei,Shigella flexneri and Shigella boydi are the main organisms of concern. Person-to person contact, faecally contaminated food, and less frequently, water are the main sources of contamination. Survival in surface water is limited to hours or days, depending on the amount of contamination and the water temperature. Shigellae are susceptible to chlorination and ultraviolet disinfection at the doses used in water treatment. E. coli is an adequate indicator for the presence and survival of Shigella in water. - Yersinia: Species of Yersinia are members of the family Enterobacteriaceae, of which some species cause diseases in humans and other mammals. Human plague, caused by Yersinia pestis, is not a waterborne disease. Other species, including Yersinia enterocolitica, Yersinia intermedia, Yersinia kristensenii, Yersinia frederiksenii and Yersinia pseudotuberculosis, may produce symptoms ranging from subclinical and mild diarrhoeal infections to rare severe infection including septicaemia. Some serotypes of Yersinia enterocolitica are more frequently associated with human disease than others. Yersinia species are susceptible to chlorination and ultraviolet disinfection at doses normally used in water treatment. E. coli is an adequate indicator for the presence and survival of Yersinia in water. - Vibrio: Species of Vibrio are members of the Vibrionaceae. Some species, most notably, strains of Vibrio cholerae, cause gastro-enteritis in humans. Vibrio species occur naturally in brackish and saline waters, and some can survive in freshwater systems. Vibrio cholerae, which causes cholera, can be divided into approximately 140 O-serovars. The strains that usually produce outbreaks of epidemic cholera are toxin-producing strains of the O1 serovar and a more recently reported serovar, O139. Some other serovars of Vibrio cholerae can also cause gastroenteritis. The primary route of transmission for cholera is contaminated water and outbreaks have also been reported following consumption of crops irrigated with sewage-contaminated water. Vibrio parahaemolyticus also causes diarrhoea, often through the consumption of raw, contaminated seafood. Vibrio fluvialis, Vibrio furnissii, Vibrio hollisae and Vibrio mimicus are also recognised as causing diarrhoea. Other species of Vibrio are associated with wound infections or septicaemia following exposure to environmental waters. Vibrio species can grow in environmental waters, particularly when temperatures rise above 10 °C and may be associated with sediments, plankton and cyanobacterial blooms. Vibrio are susceptible to chlorination and ultra violet disinfection at doses normally used in water treatment. **VIRUSES** - Norwalk-like viruses: Norwalk-like viruses (NLV) are classified within the Caliciviridae family. They are the most common cause of sporadic and epidemic viral gastro-enteritis in adultsbut are also common causes of infections in children. Many strains of NLV have been recognised and they are currently divided into two major genogroups (I and II). The main route of transmission is via person to-person contact, but food-borne transmission may occur, especially involving raw or inadequately cooked shellfish. Water-borne outbreaks have occurred as a result of sewage contamination of drinking water supplies. The limited information currently available suggests that NLV are sensitive to chlorination. As these viruses may survive in the environment longer than bacteria, the absence of E. coli may not always equate with the absence of NLV. - Hepatitis A Virus: Hepatitis A virus is a member of the Picornaviridae family of viruses, and is the only member of the Hepatovirus genus in which there is only one serotype. No animal strains are known. The virus replicates in the liver and causes acute but self-limiting hepatitis. Transmission is by direct faecal-oral route and is most common in areas of poor hygiene and poor sanitation. Waterborne outbreaks have been recognised after sewage contamination of drinking water. Hepatitis A viruses are sensitive to chlorination, but as these viruses may survive in the environment longer than bacteria, the absence of E. coli may not always equate with the absence of Hepatitis A viruses.**Other viruses:** - Enteroviruses (Picornaviridae family): are well-established indicators of human enteric viruses in the environment. This is due to the relative ease with which they can be concentrated from sewage-contaminated water and the availability of effective detection methods. Additionally, Enteroviruses replicate in the gastro-intestinal tract and are present in most populations throughout the year. The group includes poliovirus, Coxsackievirus B and echovirus. Enterovirus infections are commonly asymptomatic, but may cause flu-like symptoms, occasionally meningitis and, rarely, paralysis. Enterovirus infection does not result in gastro-enteritis unless as part of a more generalised illness. Vaccination campaigns utilising live poliovirus are undertaken world-wide resulting in widespread occurrence of the virus in the environment. Infections with other Enterovirus serotypes are common world-wide with different serotypes predominating from year to year. Water-borne transmission has not been confirmed, although as person-toperson transmission is the main route and results in many asymptomatic infections, it would be difficult to identify. - Rotaviruses (Reoviridae family) comprise six serogroups and are further divided into serotypes and genotypes. Serogroup A is the most common human rotavirus infection, although members of Group B and C can also infect humans. Infection first occurs below the age of one year and rotavirus is the most important pathogen causing gastro-enteritis of this age group. Subsequent infections throughout life are usually asymptomatic. A few waterborne outbreaks world-wide have been reported. The Adenoviruses (Adenoviridae family), which include many different serotypes, replicate in the gastro-intestinal tract and are shed into sewage. Only serotypes 40 and 41 are known to cause gastro-enteritis in humans, mostly in babies. Infection involving drinking water has not been recognised. The Astroviruses (Astroviridae family) include at least eight serotypes that infect humans, causing gastro-enteritis, particularly in children. Water-borne infections have been reported.The above viruses may survive in the environment for longer periods than bacteria, and the absence of E. coli may not be an adequate indicator for the environmental presence of these viruses in all circumstances. These viruses are sensitive to chlorination. - Classic calicivirus is the name given to a distinct group of Caliciviruses and are recognized by clear cup-shaped markings on virions when examined by electron microscopy. This group is also known as Sapporo virus or Sapporo-like viruses. They are part of the family Caliciviridae but are distinct from the NLV. No water-borne infections have been recognised. **PROTOZOA**The enteric protozoa that cause human illness are usually transmitted by the consumption of food and drink, although environmental contamination and poor hygiene are also important transmission routes. Many causes particular problems in immuno-compromised patients, particularly in people infected with HIV and individuals with T-cell deficiencies. The protozoa that are of most concern are Cryptosporidium, Giardia and Toxoplasma, although Cyclospora has been identified in a number of food-borne outbreaks. Water-borne outbreaks of infection with protozoa have been reported. - Cryptosporidium: Cryptosporidium species are the cause of a diarrhoeal disease that can last for up to several days to a few weeks. A chronic life-threatening infection with watery diarrhoea can occur in people with compromised immune systems. There have been several outbreaks of gastroenteritis linked to drinking water, contaminated swimming pool and recreational water use, and drinking water is an important identifiable source of human cryptosporidiosis. Other sources include contamination associated with farm visits and food-borne infection. Cryptosporidium oocysts have a low infectious dose (from 10 to 1000 organisms) and individual strains have been found to differ in their infectivity. Natural water sources are commonly contaminated with oocysts from animal and human faeces. Cryptosporidium species includes a number of types that are infectious to humans. The oocysts of Cryptosporidium are infectious when excreted in faecesand pass into rivers and lakes via sewage works and agricultural run-off. The oocysts are resistant to environmental conditions and disinfectants such as chlorineand can pass into drinking water when there are failures in filtration processes or contamination of source waters. There is increasing evidence that oocysts are susceptible to ultraviolet disinfection. Conventional indicator bacteria are not good indicators of Cryptosporidium contamination, and water supplies that are at risk of contamination are subject to continuous monitoring. - Giardia: Giardia species are flagellated protozoans that parasitize the small intestines of mammals, birds, reptiles and amphibians, and giardiasis is a common cause of diarrhoea. The symptoms of giardiasis range from asymptomatic to a transient or persistent acute stage, with steatorrhoea, intermittent diarrhoea, and weight loss, or to a sub-acute or chronic stage that can mimic gallbladder or peptic ulcer disease. The cysts of Giardia duodenalis are relatively resistant to chlorine, although less resistant than Cryptosporidium oocysts. The cysts can remain viable in cold water for several months. - Cyclospora: Cyclospora is a coccidian parasite that causes protracted watery diarrhoea. It occurs worldwideand is normally associated with travel to developing countries. Outbreaks linked to drinking water have been reported. Person-toperson contact is not thought to occur, because the oocysts need to mature (sporulate) under environmental conditions outside the host for one to two weeks before they become infectious. The oocysts have been reported to be relatively resistant to chlorine. - Microsporidia: Microsporidia are protozoa with characteristic morphology including a lack of mitochondria and possession of a distinctive coiled polar tube in the spores. Two species, Enterocytozoon bieneusi and Encephalitozoon intestinalis, are a common cause of chronic diarrhoea in immunocompromised individuals, and they may infect a range of agricultural animals. As viable spores are passed by infected patients, person-to-person transmission and contamination of water with human waste are potential routes of transmission. The difficulty of isolating organisms by tissue culture means that reliable information on the sensitivity of spores to chlorine is not available for all species. The relatively recent emergence of species of Microsporidia as human pathogens and the difficulties of diagnosis mean that water-borne associations cannot yet been clearly demonstrated, although spores have been found in non potable water. - Toxoplasma gondii: Toxoplasma gondii is a parasite which forms oocysts in cats, and cysts within a secondary host's (other mammals or birds) tissues. The life cycle is completed when the carnivorous primary host consumes the secondary host. Humans are infected by consuming inadequately cooked meat from infected secondary host species such as agricultural animals, or from oocysts occurring in food or water. The sporulated oocysts of Toxoplasma are very resistant to environmental conditions and disinfectants. Water-borne infections arise through oocysts, from infected wild cats, getting into drinking water. - Entamoeba histolytica: Entamoeba histolytica causes amoebic dysentery and abscesses in the liver and other organs. Water-borne infections mostly arise when consuming contaminated food or water in countries where it is endemic. Infection is common world-wide, particularly in poor countries with inadequate sanitation. Outbreaks of infection associated with drinking water are rare. 2\. Microbes Cause Food Spoilage and Decomposition: Microbes are the agents of food spoilage and decomposition of clothing and sheltering materials. The factors that allow microbes to accomplish biodegradation and carbon cycling are at work on everything organic, which includes: -- foods and grains stored in granaries, -- supermarket or refrigerator, -- natural structural materials -- textiles used for our shelters and clothing. Nothing lasts forever, and the microbial decomposition of everything organic will occur in time. Fungi and bacteria are the major microbial agents of decomposition in aerobic environments. Bacteria take over in environments that lack oxygen. 3\. Microbes Cause Infectious Disease: A microbe which is capable of causing infectious disease in an animal or plant is called a pathogen. Water purification, immunization (vaccination), and modern antibiotic therapy (all developments in the field of bacteriology) have dramatically reduced the morbidity and the mortality of infectious disease during the Twentieth Century, at least in the developed world where these are acceptable cultural practices. However, many new microbial pathogens have been recognized in the past 30 years and many \"old\" bacterial pathogens, such as Staphylococcus aureus and Mycobacterium tuberculosis, have emerged with new forms of virulence and new patterns of resistance to antimicrobial agents. 4\. Contribution to greenhouse gases: Another important impact of decomposition besides generating inorganic nutrients is to produce CO2 and CH4 (green-house gases) that is released to the atmosphere. Methanogens produce methane in natural and artificial anaerobic environments (sediments, water-saturated soils such as rice paddies, wastewater facilities, biogas facilities and anthropogenic methane production associated with fossil fuels. Agriculture is the largest emitter of the potent greenhouse gas nitrous oxide (N2O), which is released by microbial oxidation and reduction of nitrogen. 5\. Airborne Microorganisms: Airborne microorganisms include bacteria, fungi, viruses, and allergens dispersed in the atmosphere through aerosols, dust particles, and respiratory droplets. Common airborne pathogens include respiratory viruses (e.g., influenza virus, respiratory syncytial virus), bacteria (e.g., Mycobacterium tuberculosis, Legionella pneumophila), and fungal spores (e.g., Aspergillus spp., Penicillium spp). 6\. Soilborne pathogens such as fungal pathogens (e.g., Fusarium spp., Phytophthora spp.) and nematodes can cause plant diseases and reduce crop productivity. Environmental microbiologists study soil microbial communities to understand disease dynamics, develop sustainable pest management strategies, and promote soil health in agriculture. Case Study: Campylobacter and Farming: Campylobacter jejuni and Campylobacter coli are bacteria that cause food poisoning in humans; in fact, they are the most common causes of food poisoning in the UK and is very common in the USA. Commonly found in areas where there is a large concentration of farming - particularly in areas heavy in poultry and dairy farming and where there are areas of untreated surface water - it leads to diarrhoea, gastroenteritis and other gut problems in humans. It is a microbe that can also cause debilitating illness in humans and though not deadly, there is an economic impact on areas when people are off work for extended periods of time. Where prevalent, it can put a large strain on health resources. VIRULENT ACTIVITIES OF MICRO-ORGANISMS: RELATIONSHIP BETWEEN THE HOST, AGENT, AND ENVIRONMENT. ***[AGENT:]*** An ***agent*** is a factor whose presence or absence, excess or deficit is necessary for a particular disease or injury to occur. It is classified into: 1.Biological agents 2.Physical agents 3.Chemical agent 4.Nutritive agents **BIOLOGICAL AGENTS** 1\. virus 2\. bacteria 3\. protozoa 4\. fungus 5\. helmenth 6\. ectoparasite ***[PHYSICAL AGENTS]*** Temperatures; Heat, Cold, Radiation; Solar, UVR, Ionizing, High altitude *[1.]* Excessive Nutrition 2\. UnderNutrition 3\. Malnutrition. **CHARACTERISTICS OF INFECTIOUS DISEASE AGENTS** 1.Infectivity 2.Pathogenicity 3\. Virulence 4\. Immunogenicity 5\. Toxigenicity 6\. Survival [**Virulence:** R]efers to the severity of the disease. Measured by the proportion of severe or fatal case. Toxigenicity is the capacity of the agent to produce a toxin or poison. **[Infectivity:]** The capacity of an agent to produce infection or disease. Measured by the ***[secondary attack rate. ]*** **[Pathogenicity:]** The capacity of the agent to cause disease in the infected host. Measured by the proportion of individuals with clinically apparent disease. **[Survival:]** The ability of the agent to survive adverse environmental conditions. **[I*mmunogenicity*:]** The ability of the agent to induce antibody production in the host. **Host: Definition** A person (or animal) that permits lodgment of an infectious disease agent under natural conditions. The host can be the organism that gets sick, as well as any animal carrier (including insects and worms) that may or may not get sick. Although the host may or may not know it has the disease or have any outward signs of illness, the disease does take lodging from the host. The "host" heading also includes symptoms of the disease. Different people may have different reactions to the same agent. For example, adults infected with the virus *varicella (chickenpox) are more likely than children to develop* serious complications. Hosts in which a parasite attains maturity or passes its sexual stage are ***[primary]***or ***[definitive]***hosts. Those in which a parasite is in a larval or asexual state are ***[secondary]***or ***[intermediate]***hosts. A ***[transport host]*** is a carrier in which the organism remains alive but does not undergo development. **HOSTS FACTOR** (INTRINSIC FACTORS) -- INFLUENCE EXPOSURE SUSCEPTABILITY OR RESPONSE TO AGENTS,INCLUDES: 1\. Physiological e.g. pregnancy 2\. Anatomical 3\. Genetic e.g. sickle cell anemia 4\. Behavioral e.g. smoking 5\. Occupational 6\. Constitutional 7\. Cultural Once an agent infects the host, the degree and severity of the infection will depend on ***[the host's ability]*** to fight off the infectious agent.Two types of defense mechanisms are present in the host: [nonspecific] and [disease-specific]. **Environment:** The domain external to the host in which the agent may exist, survive, or originate. The environment consists of physical, climatologic, biologic, social, and economic components that affect the survival of the agents and serve to bring the agent and host into contact. **Reservoirs of Infectious Diseases:** The environment can act as a reservoir that fosters the survival of infectious agents. Examples: contaminated water supplies or food; soils; vertebrate animals. **Types of Environmental Factors** Physical, chemical, biological, Social, political, economic,population density, cultural, environmental factors that affect presence and levels of agents, homeostatic balance. **Epidemics arise when host, agent, and environmental factors are not in balance:** 1\. Due to new agent 2\. Due to change in existing agent (infectivity, pathogenicity, virulence) 3\. Due to change in number of susceptibles in the population 4\. Due to environmental changes that affect transmission of the agent or growth of the agent. **METHODOLOGY: ENVIRONMENTAL MICROBIOLOGICAL TECHNIQUES FOR STUDYING MICROBES.** To explore the vast and often hidden world of microorganisms, scientists in Environmental Microbiology employ various techniques. Each method offers insights into the structure, function, and dynamics of microbial communities in their natural habitats. These techniques range from traditional culture-based methods to advanced molecular approaches. The goal is not only to identify which microorganisms are present but also to understand their ecological roles, how they interact with each other, and their environment. Key techniques include: 1. Microscopy: From simple light microscopy to advanced electron microscopy, visualizing the morphology of microorganisms provides fundamental insights. 2. Culture Techniques: Cultivating microorganisms in controlled conditions to study their physiology, biochemistry, and to isolate pure cultures. 3. Molecular Techniques: Utilizing DNA and RNA analysis through PCR, qPCR, and next-generation sequencing to identify and quantify microbial populations without the need for cultivation. 4. Bioinformatics: Analysing sequence data and using computational tools to explore microbial genomes, understand their functions, and predict their ecological impacts. 5. Metagenomics: Sequencing the genetic material from an environmental sample as a whole, providing acomprehensive view of the microbial community\'s diversity. **Challenges Facing Microbiology in Nigeria** - **Inadequate Funding:** Education is one of the most valuable tools for building a sustainable future. Since 2015, the United Nations Educational Scientific and Cultural Organizations (UNESCO) Member States to which Nigeria belong to agreed on a level of educational funding of 4 to 6% of GDP or 15 to 20% of public expenditure (annual budget), but most countries, Nigeria inclusive, have not yet reached this threshold (Ojo, 2023). Figure 1 shows the percentages of annual budget allocation to education in Nigeria after the UNESCO agreement. The inconsistencies in the allocations to education show that the country is not giving the sector the needed priority. One of the major challenges facing microbiology education in Nigeria is inadequate funding. In 2022, lecturers under ASUU embarked on an eight-month strike to protest poor funding of tertiary institutions and better working conditions. Thegovernment has not been providing enough funds to support research and development in this field. This inconsistent allocation to education has made it difficult for microbiology departments and institutions to perform at their optimal level as it contributes significantly to lack of modern equipment and facilities for research. - **Lack of Adequate Laboratory facilities and Infrastructure** Insufficient laboratories equipped with modern tools and technologies hinder students\' practical understanding of microbiological concepts. Without proper laboratory equipment and outdated facilities, students miss out on appropriate practical hands-on experience, limiting their ability to apply theoretical knowledge to real-world scenarios. The deficiency extends to basic tools like incubators, autoclaves, ovens, microscopes, and fume hoods, which are crucial for effective microbiology education. Many microbiology laboratories resort to makeshift solutions during practical sessions, such as using stoves and pressure pots instead of autoclaves for sterilizing glassware and media due to limited or nonexistent budgets. Discussing advanced equipment like a Thermocycler, Gel electrophoresis apparatus, electron microscope, and sequencing machine might be comparable to asking for the impossible, akin to requesting the sun, moon, and stars. Consequently, graduates from these laboratories may lack global competitiveness and might not be motivated to pursue advanced degrees in the field (Aishat, 2019). While universities, especially the older ones, possess some tools and equipment, they are often insufficient, and some are in poor states. In practical sessions, there is a scarcity of equipment for students, leading to overcrowded and inattentive learning environments. Moreover, universities often admit more students than their facilities canaccommodate, exceeding allotted admission quotas, particularly for programs lacking regulatory bodies like microbiology (Amini-Philips & Akpoyowaire, 2016). Presently, there are no companies in Nigeria manufacturing consumables and reagents essential for practical sessions. The necessity to import these items makes them challenging to obtain, rendering practical sessions ineffective. The prolonged processing time for orders and quotes, coupled with the time-sensitive nature of scientific professions, results in decreased productivity for tutors and limited exposure for students. - Another challenge, though not peculiar tomicrobiology education, is inadequate power supply. This makes the use of electrical devices such as projectors and electronic laboratory equipment difficult. This also limits students, for example, restricting studying at night. Furthermore, the availability of current textbooks and digital resources in many Nigerian institutions is woefully inadequate. Even in private institutions that offer some online resources, the challenge of poor internet connectivitysignificantly hampers access. A dependable Internet connection plays a crucial role in enhancing learning and teaching, facilitating out-of-class engagement. Without reliable internet access, face-to-face learning remains the primary mode of interaction (Sofola, 2014). Additionally, the Internet serves as a platform for open educational resources (Mishra, 2017). Accessing the Internet for relevant microbiology learning materials, as suggested by Guarner and Niño (Guarner & Niño, 2016), can significantly augment student comprehension. Although there is increased access due to the sale of internet data by telecom providers, students often find this cost-prohibitive. Some universities in countries like Nigeria are making efforts to establish internet bandwidth on their campuses, but this is currently limited to specific locations (Sofola, 2014). Lastly, importing books is an expensive endeavor, emphasizing the need to develop locally relevant educational materials and ensure they stay current with contemporary content (Aishat, 2019). - **Education and Training:** In Nigeria, microbiology education faces a significant challenge due to a shortage of qualified experts to teach aspiring microbiologists (Aishat, 2019). The effectiveness of universities in producing competent graduates hinges on the availability and calibre of instructors. Public universities in Nigeria grapple with a high student-to-faculty ratio, resulting in inadequate supervision during lectures, practical sessions (Sofola, 2014), and examinations. Microbiology graduates often fall into three categories: those leaving the field for non-microbiology careers, those practising microbiology, and those pursuing postgraduate degrees due to job scarcity. The predominant trend is graduates opting for non-microbiology paths. The migration of skilled microbiologists abroad for further studies exacerbates the brain drain, with Nigerian professionals contributing to microbiology abroad (Bassioni et al., 2016). Academic staff also bear heavy administrative burdens, straining their capacity and impeding self-development, leading to diminished productivity. Additionally, a major challenge stems from the absence of dedicated funds for microbiology training in Nigeria, although there is the Tertiary Education Trust Fund (TETFund), which is being used to fund research, conference attendance and postgraduate training (Sofola, 2014); however, it is highly competitive, and there are reports of nepotism and corruption in its application processes (Balogun et al., 2018). This lack of financial resources makes training and further education difficult. Over the past two decades, there has been a noticeable decline in the quality of microbiology staff in Nigeria, evident to anyone cognizant of microbiology\'s societal significance (Longe et al., 2005). - **Outdated Curricula:** Many educational institutions persist in using outdated curricula established since the inception of their programs. Lecturers often fail to update their teaching materials, relying on obsolete notes that do not align with current realities. - Jiboyewa & Umar, 2015). Additionally, several institutions neglect to cover contemporary microbiology topics like genomics, transcriptomics, proteomics, and synthetic biology, either due to a lack of expertise or insufficient teaching resources. These subjects embody essential knowledge crucial for the future development of microbiologists. By investing in microbiology education, particularly in areas such as bioremediation and waste management, Nigeria could equip future professionals to address environmental challenges like the contamination in Ogoniland and other regions of the Niger Delta. This proactive approach would not only save the country significant financial resources but also alleviate health and environmental issues stemming from improper waste disposal. - **Poor Numeration:** In Nigeria, poor remuneration stands out as a significant challenge in the field of Microbiology. Professionals in this field often face inadequate financial compensation, which can demotivate individuals and hinder the attraction and retention of skilled talent. Insufficient salaries impact not only the livelihoods of microbiologists but also the overall growth and advancement of the discipline in the country, as it may discourage dedication and investment in this crucial scientific field. Addressing this issue is crucial for fostering a robust and effective microbiology education in the country. - Limited Job Opportunities: The recruitment of microbiologists for careers in Nigeria is a significant problem exacerbated by changes in career expectations due to COVID-19 and post-COVID scenarios. Limited job opportunities in microbiology and the inability of the job market to absorb all graduates contribute to unemployment or underemployment. In response, the Nigerian government mandated entrepreneurship education in university curricula to equip students with skills for starting their own businesses. However, the non-professionalization of microbiology prevents graduates from practising their learned skills independently. - **Public Perception/Lack of Awareness:** Misconceptions and lack of awareness can hinder the progress of microbiological research and applications. There is a need to enhance public understanding and appreciation of microbiology. Let us take the issue of antimicrobial resistance, for example. According to a study on public awareness of antimicrobial resistance in Nigeria, only 8.3% of the respondents had good knowledge of antimicrobial resistance (Chukwu et al., 2020). The study also revealed that 66.8% of the respondents had taken antibiotics in the last six months, out of which 31.3% were without a prescription. This indicates a lack of awareness of the proper use of antibiotics and the dangers of antimicrobial resistance. Since issues that deal with microbes have a direct bearing on the human condition, it is critical that the public at large become better grounded in the basics of microbiology. Public literacy campaigns must identify the issues to be conveyed and the best avenues for communicating those messages. Public health interventions and programs have been shown to prevent and control diseases, improve access to healthcare, promote healthy behaviors, and address social determinants of health. For example, investing in smoking cessation programs can help individuals quit smoking, reducing their risk of developing lung cancer and other diseases. In addition, there are several funding opportunities available for microbiology research in Nigeria. For instance, ScientifyRESEARCH provides funding for microbiology research and medical researchers, including research grants, fellowships, and awards (RESEARCH FUNDING DATABASE, 2024). In addition, increased funding can help improve the quality of education in Microbiology. About 110 tertiary institutions in Nigeria offer Microbiology as a course of study. However, these institutions still lack vital research skills and technology. With increased funding, these institutions can acquire the necessary equipment and technology to provide students with a more comprehensive education (Mohammed et al., 2015). Public health interventions and programs also have a positive impact on communities. They can reduce the burden of diseases and injuries, increase productivity, and improve the overall quality of life. For example, investing in safe drinking water programs can reduce the risk of waterborne illnesses, promoting the health and well-being of communities. One of the key benefits of investing in public health is the prevention and control of diseases. Public health interventions such as vaccination programs, disease surveillance, and outbreak investigations can help prevent the spread of infectious diseases. By identifying and containing outbreaks early, public health professionals can prevent diseases from spreading throughout communities and causing widespread illness and death. Investing in public health also promotes healthy behaviors that can prevent chronic diseases such as heart disease, diabetes, and cancer. Public health interventions such as education campaigns, community-based programs, and policy changes can encourage people to make healthier choices, such as eating a balanced diet, being physically active, and not smoking. Governments, organizations, and communities must work together to prioritize public health investments to create a healthier and more equitable future for all. Non-profit organizations play a critical role in investing in public health by providing funding for research, supporting public health programs, raising awareness, and advocating for policies that promote public health. One important way non-profit organizations invest in public health is by providing funding for research. Research is critical to understanding the causes, risk factors, and effective treatments for a wide range of health issues. Non-profit organizations can provide funding for both basic research, which focuses on understanding the fundamental mechanisms of disease, and applied research, which focuses on developing new treatments and interventions. For example, the Bill and Melinda Gates Foundation is a non-profit organization that invests in global health programs. The foundation has supported public health programs that have successfully reduced the incidence of diseases such as HIV/AIDS, tuberculosis, and malaria in low-income countries. Non-profit organizations can also work to raise awareness about important public health issues. This can include educating the public about the risk factors for specific health issues, promoting healthy behaviors, and advocating for policies that promote public health. TOPIC: Cultural methods and preservation of cultures **Abstract** Microbiology has been largely developed thanks to the discovery and optimization of culture media. The first liquid artificial culture medium was created by Louis Pasteur in 1860. Previously, bacterial growth on daily materials such as some foods had been observed. These observations highlighted the importance of the bacteria\'s natural environment and their nutritional needs in the development of culture media for their isolation. A culture medium is essentially composed of basic elements (water, nutrients), to which must be added different growth factors that will be specific to each bacterium and necessary for their growth. The evolution of bacterial culture through the media used for their culture began with the development of the first solid culture medium by Koch, allowing not only the production of bacterial colonies, but also the possibility of purifying a bacterial clone. The main gelling agent used in solid culture media is agar. However, some limits have been observed in the use of agar because of some extremely oxygen-sensitive bacteria that do not grow on agar media, and other alternatives were proposed and tested. Then, the discovery of antimicrobial agents and their specific targets prompted the emergence of selective media. These inhibiting agents make it possible to eliminate undesirable bacteria from the microbiota and select the bacteria desired. Thanks to a better knowledge of the bacterial environment, it will be possible to develop new culture media and new culture conditions, better adapted to certain fastidious bacteria that are difficult to isolate. Keywords: Culture media; Enriched media; Gelling agents; Liquid and solid media; Selective media. [Introduction] The evolution of culture in microbiology encompasses significant developments that have transformed the field from its inception to the present day.From the early Beginnings Antonie van Leeuwenhoek (1670s)Was often referred to as the \"Father of Microbiology,\" van Leeuwenhoek was the first to observe microorganisms using a single-lens microscope he developed. He described bacteria and protozoa, laying the foundation for microbiology.Louis Pasteur (1850s-1860s) experiments debunked the theory of spontaneous generation, demonstrating that microorganisms are responsible for fermentation and spoilage. He developed pasteurization and vaccines for rabies and anthrax, significantly advancing the field. The Development of Pure Culture Techniques came about by the following: 1.Robert Koch (1870s-1880s): \- Koch developed methods for cultivating bacteria on solid media, particularly agar, allowing the isolation of pure cultures. His postulates provided a framework for linking specific microbes to specific diseases. 2.Agar and Petri Dishes (1880s): \- Fannie Hesse suggested using agar as a solidifying agent for bacterial cultures, leading to the development of the Petri dish by Julius Richard Petri. These innovations became standard tools in microbiology labs. The modern Advances are as follows: 1.Genomics and Metagenomics (2000s-present): \- Advances in sequencing technologies have allowed for the complete sequencing of microbial genomes. Metagenomics has enabled the study of microbial communities in various environments without the need for culturing, revealing the vast diversity of the microbial world. 2.Synthetic Biology and CRISPR: \- Synthetic biology aims to design and construct new biological parts, devices, and systems. The CRISPR-Cas9 system, derived from bacterial immune mechanisms, has become a powerful tool for genetic engineering, allowing precise manipulation of microbial genomes. 3.Microbiome Research: \- The Human Microbiome Project and similar initiatives have highlighted the importance of microbial communities in human health and disease, leading to a better understanding of the symbiotic relationships between humans and their microbiota. The evolution of culture in microbiology has progressed from the simple observation of microorganisms to sophisticated techniques that allow detailed genetic and functional analysis. Each technological advancement has opened new avenues for research and applications, profoundly impacting medicine, industry, and our understanding of life itself. **[Definition]** Culture In microbiology refers to the propagation of microorganisms ina controlled environment, typically outside their natural habitat. This involves growing microbial cells, tissues, or organisms in specific nutrient conditions to study their characteristics, physiology, and behavior. The primary objective of culturing is to isolate and maintain pure colonies of microorganisms for examination and experimentation. Whereas media(or medium in singular form) in microbiology are substances that provide the necessary nutrients and environment for microorganisms to grow. These media can be in solid, liquid, or semi-solid forms and contain essential nutrients such as carbohydrates, proteins, vitamins, and minerals required for microbial growth. Media can be classified based on their composition, purpose, and physical state. **[Classification and types of culture media]** Culture media in microbiology are classified based on several criteria: their physical state, chemical composition, and functional purpose. Below are the classifications and types of culture media. [Classification Based on Physical State] 1\. Solid Media \- Contains agar (typically 1.5-2%) as a solidifying agent. \- Used for isolating and enumerating bacteria. \- Example: Nutrient Agar, Blood Agar. 2\. Liquid (Broth) Media \- No solidifying agent, remains in liquid form. \- Used for growing large volumes of bacteria or for fermentation studies. \- Example: Nutrient Broth, Tryptic Soy Broth. 3\. Semi-Solid Media \- Contains a lower concentration of agar (0.3-0.5%). \- Used for motility studies and detecting the production of gases. \- Example: SIM (Sulfide Indole Motility) Medium. [Classification Based on Chemical Composition] 1.Defined (Synthetic) Media \- The exact chemical composition is known. \- Used for specific experimental needs where the nutritional requirements of the microorganisms are known. \- Example: Minimal Media (e.g., M9 Medium). 2\. Complex Media \- Contains complex ingredients such as yeast extract, peptone, and beef extract, where the exact chemical composition is not fully defined. \- Supports the growth of a wide range of microorganisms. \- Example: LB (Luria-Bertani) Medium, Tryptic Soy Agar. [Classification Based on Functional Purpose] 1\. General Purpose Media \- Supports the growth of a wide variety of microorganisms \- Example: Nutrient Agar, Tryptic Soy Agar. 2\. Selective Media \- Contains agents that inhibit the growth of certain microorganisms while allowing the growth of others. \- Used for isolating specific types of microorganisms. \- Example: MacConkey Agar (selects for Gram-negative bacteria), Mannitol Salt Agar (selects for staphylococci). 3\. Differential Media \- Contains indicators that differentiate between microorganisms based on their biochemical characteristics. \- Example: Blood Agar (differentiates based on hemolysis), Eosin Methylene Blue (EMB) Agar (differentiates based on lactose fermentation). 4\. Enrichment Media \- Contains specific nutrients to enhance the growth of particular microorganisms. \- Example: Selenite F Broth (for Salmonella enrichment), Buffered Charcoal Yeast Extract (BCYE) Agar (for Legionella). 5.Transport Media \- Used to maintain and preserve specimens during transport to the laboratory. \- Example: Stuart's Transport Medium, Amies Transport Medium. 6.Anaerobic Media \- Contains reducing agents to create an anaerobic environment. \- Used for growing anaerobic microorganisms. \- Example: Thioglycolate Broth, Anaerobic Jar systems. [Examples of Common Culture Media] 1\. Nutrient Agar/Broth: General purpose, complex medium used for the growth of non-fastidious microorganisms. 2\. MacConkey Agar: Selective and differential medium used for isolating Gram-negative enteric bacteria and differentiating them based on lactose fermentation. 3.Blood Agar: Enriched and differential medium used for the cultivation of fastidious organisms and the detection of hemolytic activity. 4\. Mannitol Salt Agar: Selective and differential medium used for isolating Staphylococcus species and differentiating them based on mannitol fermentation. 5.Sabouraud Dextrose Agar: Used for cultivating fungi and yeast. 6.Chocolate Agar: Enriched medium used for growing fastidious respiratory bacteria, such as Haemophilus influenza and Neisseria species. **[Cultural methods]** Cultural methods in microbiology refer to the techniques used to cultivate, isolate, and maintain microorganisms under laboratory conditions. These methods enable the growth of microorganisms in controlled environments to study their characteristics, behaviors, and interactions. Cultural methods are essential for identifying pathogens, testing antimicrobial susceptibility, conducting research, and producing industrially important microbial products. Types of Cultural Methods 1.Streak Plate Method -Description: This technique involves spreading a small amount of microbial sample over the surface of an agar plate using a sterile loop to isolate individual colonies. -Purpose: Isolating pure cultures from a mixed population. 2\. Pour Plate Method -Description: In this method, a diluted microbial sample is mixed with molten agar and poured into a petri dish. The agar solidifies, and colonies grow both on the surface and within the medium. -Purpose: Estimating the number of viable microorganisms in a sample and isolating pure colonies. 3\. Spread Plate Method -Description: A small volume of diluted microbial sample is spread evenly across the surface of an agar plate using a sterile spreading tool. \- Purpose: Counting colonies to estimate the number of microorganisms in a sample. STREAK CULTURE Streaking is a technique used in microbiology for the isolation of single colonies of microorganisms, either from a mixed species or from the same species. This technique is mostly applicable to bacteria, but is also used for some yeast. It is an old technique that has been in use since the time of Robert Koch. It was first demonstrated by Loeffler and Gaffky in Koch's laboratory. It is a mechanical isolation technique used in microbiology, commonly known as the 'streaking method'. Objectives of Streak Plate Method 1\. To obtain a pure culture of bacteria from a mixed culture 2\. To obtain well-isolated colonies 3\. To propagate bacteria [Principle of Streak Plate Method] The streak plate method is based on the principle of dilution. It can be described as a rapid qualitative isolationtechnique. The main criterion of isolation is to obtain a reduced number of colonies. In this technique, a loopful ofculture is spread on an agar plate to get individual cells far apart enough from each other. The streaking methodgradually dilutes the inoculum such that the bacterial cells can be counted as colony forming units (CFUs). Thestreak plate method is based on dilution during the process of mechanical spreading of inoculum over the surfaceof solidified culture media in order to obtain well-isolated colonies of the sample at the terminal streaks. First, letus understand the microbial culture. Microbial cultures are of two types: 1\. Mixed Culture: two or more species of microorganism or bacteria are present in mixed culture. 2\. Pure culture: single species of microorganism or bacteria is present in Pure culture. In nature, bacteria exist inmixed populations. The streak plate method is widely used to isolate pure culture. [Types of Streak Plate Method] Based on the pattern of streaking, the streak plate method can be classified into 4 types:QuadrantStreaking,T-Streaking, Continuous Streaking, and Radiant Streaking. 1\. Quadrant Streaking It is the most commonly used and the most preferred method where four equal-sized sections of the agar plate arestreaked. It is also referred to as the "four-quadrant streak" or "four sectors" or "fourway streak" method. In thismethod, each plate is divided into four equal sectors and each adjacent sector is streaked sequentially. The sectorwhich is streaked first is called the first sector or the first quadrant, and it has the highest concentration ofinoculum. Gradually the second, third, and fourth quadrants will have diluted inoculum. By the time the fourthquadrant is streaked, the inoculum is highly diluted giving rise to isolated colonies following the incubation. 2\. T-Streaking: It is another method of streaking where the agar Petri plate is divided into three sections and each section isstreaked. Hence, this method is also known as the "three-sector streak" method. The media is divided into threesections by drawing a letter "T" and each adjacent section is streaked sequentially. By the time the final section isbeing streaked, the inoculum is diluted to the point to give rise to isolated colonies following the incubation. Mostlydiscontinuous fashion of streaking is followed; however, a continuous fashion can also be used in the very dilutespecimen. As in quadrant streaking, it is difficult to culture two or more samples in a single 10 cm plate using thismethod. 3\. Continuous Streaking It is another commonly followed method where an inoculum is evenly distributed in a single continuous movementfrom starting point to the center of the plate. There is no need to divide the plate and sterilize the loop during theprocess. It is easy and quick; however, the problem is that we can use it only if the inoculum is either very dilutedor we just have to propagate pure culture rather than isolate one. We can divide the 10 cm Petri plate into differentsections (mostly 2 to 6), and in each section, we can streak different specimens following this method. Hence, it isused in the clinical laboratory to culture urine, sputum, pus, etc. if multiple samples have arrived at a single time.This will allow us to save media and get maximum output using a minimum resource. 4\. Radiant Streaking It is another method of streaking where the inoculum is first streaked at one edge and spread in vertical lines abovethe edge. Finally, the vertical lines are cross streaked diagonally. This method is suitable to propagate pure culture,and also in the case of a dilute specimen. There are other modified forms of streaking like: 5\. Semi-quantitative Streaking It is routinely followed in urine culture. It is a modified form of continuous streaking. In this method, a calibratedloop (usually a loop of 1 or 2μl) is used to streak a certain volume of the liquid specimen. A loopful of the specimenis streaked in a horizontal line in the middle of the Petri plate, and the specimen is spread all over the plate in asingle continuous back and forth movement. This method allows us to approximately quantify the viable load (in a range, not an exact number) as well as get the pure culture in a single go. 6\. Zigzag Streaking It is another form of continuous streaking where a loopful of the specimen is streaked all over the plate in a zigzagpattern in a single continuous movement. It is commonly done to propagate the pure culture and culture them inlarge quantities. 7\. Lawn Culture method or Carpet culture method It is employed when large amount of growth is required and used for Antibiotic sensitivity test, on each agar plate,streak the bacteria by first making a vertical line, then spreading this left to right (and top to bottom), rotating theplate 60 degrees clockwise and again spreading the bacteria left to right (and top to bottom), and then rotating theplate another 60 degrees clockwise and spreading the bacteria again. Note: The bacteria should all be the samecolor on your plates. Color has been added in this diagram to help clarify the procedure. Uses for antibioticsusceptibility testing: It is useful for antibiotic susceptibility testing by disk diffusion method and Bacteriophagetyping. Materials Required: The following apparatus is required for the streak plate technique. 1\. Bunsen Burner 2\. Nichrome Wire Loop 3\. Sterile Nutrient Agar plates 4\. Mixed Culture of bacteria [Procedure or Protocol of Streak Plate Method] The general procedure of the streak plate method can be summarized as: 1\. Arrange all the requirements, put on the PPE, sterilize the work surface, and allow all the samples and media tocome to room temperature if were refrigerated. 2\. If the sample is very concentrated then dilution can be helpful to get the isolated colonies. (But it is notcompulsory as the sample will be diluted during the streaking process.) 3\. Sterilize the inoculating loop by flaming and allow it to cool. Pick a small portion of the isolated colony. (if thesample is in the suspension, then take a loopful of the sample).The inoculating procedure is different according to the method of streaking. [Applications of Streak Plate Method] 1\. Used to obtain a pure culture from the mixed culture in order to perform morphological, biochemical, andmolecular tests to identify and for other applications. 2\. Used to define the specimen as pure or mixed species. 3\. Used to study colony characters of bacteria. 4\. Used to produce a colony of genetically identical individuals. 5\. Used in inoculation of clinical specimens in diagnostic laboratories to grow isolated colonies of pathogen. LAWN CULTURE Lawn cultures are prepared by flooding the surface of the plate with liquid culture or suspension of the bacterium,pipetting off the excess inoculum, and incubating the plate. Alternatively, the surface of the plate may be inoculatedby applying a swab soaked in the bacterial culture or suspension. After incubation, lawn culture provides a uniformgrowth of the bacterium. Uses: 1\. Antibiotic susceptibility testing: It is useful for antibiotic susceptibility testing by disk diffusion method. 2\. Bacteriophage typing. STROKE CULTURE Stroke culture is made in tubes containing agar slope or slant. Slopes are seeded by lightly smearing the surface ofagar with a loop in a zig-zag pattern taking care not to cut the agar. It is employed for providing pure growth of thebacterium for slide agglutination