Microbiology Theory Lec One PDF

LECTURE ONE INTRODUCTION TO MICROBIOLOGY Nabaz Hama Rashid Assistant Lecturer  Microbiology: The study of living things too small to be seen without magnification. Microorganisms or microbes- these microscopic organisms commonly called “germs, viruses, agents…” but not all c...

LECTURE ONE INTRODUCTION TO MICROBIOLOGY Nabaz Hama Rashid Assistant Lecturer  Microbiology: The study of living things too small to be seen without magnification. Microorganisms or microbes- these microscopic organisms commonly called “germs, viruses, agents…” but not all cause disease and many more are useful or essential for human life. Leeuwenhoek’s microorganisms grouped into six categories as follows: Fungi Bacteria Protozoa Archaea Algae Small animals  A disease causing microorganisms called pathogens (3% of all known microbes) The others are non pathogenic (97%), the beneficial microbes are 87%. Microbes live on and in our bodies e.g. skin, in the mouth and intestine are known as Normal Flora Microorganisms Some of them cause disease accidentally and known as opportunistic pathogens (10%) Diseases caused by microbes are called infectious disease Ubiquitous microbes means that they are virtually found everywhere in or on the body and in different environment of the globe  Many bacteria and fungi are Saprophytes, which aid in fertilization by returning inorganic nutrients to the soil. Saprophytes break down dead and dying organic materials (plants and animals) into nitrates, phosphates, carbon dioxide, water and other chemicals necessary for plant Microorganisms growth. Saprophytes also destroy papers, feces and other biodegradable matters, although they cannot break down most plastics or glass Nitrogen-fixing bacteria, that live in the root nodules of certain plants called legumes are able to return nitrogen from the air to the soil in the form of ammonia for use by other plants  Fungi Eukaryotic (have membrane-bound nucleus) Obtain food from other organisms Possess cell walls Composed of : Molds – multicellular; have hyphae; reproduce by sexual and asexual spores Yeasts – unicellular; reproduce asexually by budding; some produce sexual spores  Protozoa Single-celled eukaryotes Similar to animals in nutrient needs and cellular structure Live freely in water; some live in animal hosts Asexual (most) and sexual reproduction Most are capable of locomotion by: Pseudopodia – cell extensions that flow in direction of travel Cilia – numerous, short, hairlike protrusions that propel organisms through environment Flagella – extensions of a cell that are fewer, longer, and more whiplike than cilia  Algae Unicellular or multicellular Photosynthetic Simple reproductive structures Categorized on the basis of pigmentation, storage products, and composition of cell wall  Bacteria and Archaea Unicellular and lack nuclei Much smaller than eukaryotes Found everywhere there is sufficient moisture; some found in extreme environments Reproduce asexually Two kinds Bacteria – cell walls contain peptidoglycan. Archaea – cell walls composed of polymers other than peptidoglycan  Viruses Obligate intracellular parasites Much simpler than cells- basically a small amount of DNA or RNA wrapped in protein and sometimes by a lipid membrane Individuals are called a virus particle or virion Depend on the infected cell’s machinery to multiply and disperse  Life What characteristics must an organism have in order to considered alive? Metabolism: Transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life. Reproduction: The ability to produce new individual organisms either asexually, from a single parent organism, or sexually, from at least two parent organisms.  The Golden Age of Microbiology An explosion of interest in microbiology centered on four main questions the answers to which provide a framework leading to the modern age of microbiology. these questions are: 1. Is spontaneous generation of microbial life possible? 2. What causes fermentation? 3. What causes disease? 4. How can we prevent infection and disease?  The modern age of microbiology A. Examining the basic chemical reactions of life. B. Determining how genes work: Genetics Molecular biology Recombinant DNA technology. C. Determining the role microorganisms play in the environment Worldwide Infectious Diseases Affecting Health Sciences Increasing number of drug resistant strains including Nosocomial and Community Acquired microorganisms MRSA Methicillin Resistant Staphylococcus aureus VRE Vancomycin Resistant Enterococcus VRSA Vancomycin Resistant Staphylococcus aureus MDR-TB Multidrug Resistant Tuberculosis Worldwide Infectious Diseases Affecting Health Sciences Increasing number of emerging diseases (SARS, AIDS, hepatitis C, viral encephalitis) Other diseases previously not linked to microorganisms now are (gastric ulcers, certain cancers, multiple sclerosis)  Medical Microbiology It's the study of organisms that cause diseases to humans (pathogenic organisms). The relationship between microorganism and the disease, e.g. S. typhi cause typhoid fever. Characteristics of microorganism causing disease, and how microorganism cause disease as invasion of tissue or by producing toxic products. Mechanism of disease establishment called Pathogenesis. Prevention of infection: by vaccination & quarantine.  Food Microbiology Microorganism (M.O.) used in food processing and ripening are not pathogenic. M.O. can cause food infection & poisoned food Preservation of food: drying, salting, freezing, jamming, canning & use of preservatives (chemicals such as sodium benzoate & sodium nitrite). The method of preservation must be suitable for the food type and must retain food quality and prevent its destruction by M.O. Pharmaceutical Microbiology It’s the use of M.O. in the production of pharmaceutical products such as antibiotics, enzymes and vitamins. Deal with check of contamination and spoilage of pharmaceutical preparation by adding preservative. Use different sterilization techniques and preservation of pharmaceutical products. Proper use of antibiotic and chemotherapeutic agent. Agricultural Microbiology Deal with the N (nitrogen), C (carbon) and S (sulfur) cycle in nature. Fertility of soil. Disease of plants. M.O. in ruminants used for digestion in the rumen. Environmental Microbiology It becomes important branch because the concern about pollution of soil, air, water, sewage, food and dairy products. Also cycling of elements by microbial, environmental and geochemical processes In addition, the biodegradation of toxic chemicals by various microorganisms is being used as method for cleaning up hazardous materials found in soil and water Bioremediation Bioremediation uses living bacteria, fungi, and algae to detoxify polluted environments