Infection Control and Occupational Safety 2023-2024 PDF

Faculty of Applied Health Sciences Technology Menoufia University Infection Control and Occupational Safety For 3rd year Applied Health Sciences Technology Students BY Clinical MICROBIOLOGY staff members NATIONAL LIVER INSTITUTE, MENOUFIA UNIVERSITY...

Faculty of Applied Health Sciences Technology Menoufia University Infection Control and Occupational Safety For 3rd year Applied Health Sciences Technology Students BY Clinical MICROBIOLOGY staff members NATIONAL LIVER INSTITUTE, MENOUFIA UNIVERSITY 2023-2024  ‫رؤية الكلية‬ ‫كلية رائدة تتميز بتخريج تكنولوجي صحي ذو كفاءة عالية قادر علي المنافسة في سوق العمل محليا واقليميا‬ ‫لالرتقاء بمستوي الخدمات الصحية‪.‬‬ ‫رسالة الكلية‬ ‫تخريج تكنولوجي صحي ملتزم باألخالقيات المهنية متقن للمهارات التقنية المتخصصة اتي تؤهله للمساعدة‬ ‫في تقديم رعاية صحية متميزة وأمنة مبنية علي االدلة والبراهين تخدم مختلف المؤسسات الصحية‪.‬وأن‬ ‫يكون الخريج قادر علي المشاركة في البحث العلمي وخدمة المجتمع ومهيأ للتعليم المستمر والعمل الجماعي‬ ‫متمتعا بمهارات االدارة من خالل تقديم برامج متنوعة تلتزم بمعايير الجودة التعليمية‪.‬‬  Course Description Infection control and occupational safety (OFRIS003): To provide students with sufficient knowledge, skills, and attitudes essential for safe practice and proper infection prevention and control procedures in different types of healthcare organizations and services. 1 Table of content Table of Contents Chapter (1): Chain of infectionand Health care associated infections (HCAIs).......3 Chapter (2): Standard Precaution for Infection Control..........................................20 Chapter (3): Transmission-Based Precautions.........................................................26 Chapter (4): Aseptic Technique...............................................................................31 Chapter (5): Waste Management.............................................................................35 Chapter (6): Needle stick injury...............................................................................44 Chapter (7): Bloodborne Pathogens.........................................................................47 Chapter (8): Post-exposure prophylaxis to blood borne pathogens.........................55 Chapter (9): Disinfection and Sterilization..............................................................61 Chapter (10): Antimicrobial Resistance and prevention of MDROs......................82 Chapter (11): Infection control practice in the laboratory.......................................87 2 Table of content  Chapter (1): Chain of infection Intended learning outcomes (ILOS) 1- To define chain of infection. 2- To describe six links of chain of infection. 3- How to break chain of infection. Definitions Infection: is the invasion of body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Colonization: is the presence of bacteria on a body surface (like on the skin, mouth, intestines, or airway) without causing disease in the person. Inflammation is part of the response of the body tissues to harmful stimuli. The stimuli can be irritants, damaged cells, or pathogens. Definition of Chain of infection Certain conditions must be met for a microbe or infectious disease to be spread from person to person. This process is known as the chain of infection which is shown in Fig (1,2,3). 3 Table of content 4 Table of content There are six steps in the chain of infection and transmission will only take place if all six links are intact. 1. The pathogen The first link in the chain of infection is the infectious agent or pathogen which can take the form of: Viruses – such as Influenza A, shingles and Hepatitis Bacteria – including Lyme disease and Leptospirosis Fungi – for example Candidiasis and Aspergillosis Parasitic protozoan diseases – such as Malaria, Giardia and Toxoplasmosis Prions – which are the cause of rare progressive neuro-degenrative disorders such as Creutzfeldt-Jakob disease (CJD) 5 Table of content How well any pathogen is able to thrive depends on three factors: Its pathogenicity – its ability to produce disease Its degree of virulence – its severity or harmfulness Its invasiveness – its tendency to spread 2. The reservoirs A reservoir is the principal habitat in which a pathogen lives, flourishes and is able to multiply. Common reservoirs for infectious agents include humans, animals or insects and the environment. Human reservoirs In humans, there are two forms of reservoir: acute clinical cases (in which someone is infected and is displaying signs and symptoms of the disease); and carriers (where someone has been colonized with an infectious agent but is not unwell. Acute clinical cases are more likely to be diagnosed and treated which means that the patient’s contacts and normal activities will normally be restricted. Carriers, however, can present more of a risk to those around them because they do not display any signs or symptoms of illness. Carriers can be further subdivided into four main types: Incubatory carriers – people who are infectious even before their own symptoms start In apparent carriers – in which an individual is able to transmit an infection to others, without ever developing the infection themselves 6 Table of content  Convalescent carriers – people who are in the recovery phase of their illness but who continue to be infectious Chronic carriers – anyone who has recovered but who continues to be a carrier for infection. Animal & insect reservoirs Examples of animal or insect reservoirs include Lyme disease (which is transmitted via ticks); Rabies (which is transmitted by dogs, cats, foxes and bats); and Salmonella (which is transmitted by poultry, cattle, sheep and pigs). Any infectious disease that is transmitted under natural conditions from animal to human is referred to as zoonosis. Environmental reservoirs The environment contains a large number of reservoirs of infection, including soil (which acts as a reservoir for Clostridium tetani, the causative agent of tetanus) and water (which is a reservoir for Legionella pneumophila, the causative agent of Legionnaire’s disease). 3. The portal of exit The portal of exit is any route which enables a pathogen to leave the reservoir or host. In humans the key portals of exit are: Alimentary – via vomiting, diarrhoea or biting Genitourinary – via sexual transmission Respiratory – through coughing, sneezing and talking Skin – via skin lesions Trans-placental – where transmission is from mother to foetus 7 Table of content 4. The mode of transmission The two main ways that an infection can be transmitted from its reservoir to a susceptible host are via direct transmission or indirect transmission. Direct transmission tends to be instantaneous and occurs when there is direct contact with the infectious agent. Examples include tetanus, glandular fever, respiratory diseases and sexually transmitted diseases. Indirect transmission can occur through animate mechanisms such as fleas, ticks, flies or mosquitoes or via inanimate mechanisms such as food, water, biological products or surgical instruments. Indirect transmission can also be airborne, in which tiny particles of an infectious agent are carried by dust or droplets in the air and inhaled into the lungs. 5. The portal of entry The portal of entry is the mean by which an infection can enter a susceptible host. Portals of entry into the human body include: Inhalation (via the respiratory tract) Absorption (via mucous membranes such as the eyes) Ingestion (via the gastrointestinal tract) Inoculation (as the result of an inoculation injury) Introduction (via the insertion of medical devices) 6. The susceptible host The last link in the chain of infection is the susceptible host. How susceptible any host will be, depends on a variety of factors: Their age – and in particular if they are very young or very old 8 Table of content  Whether there is any presence of malnutrition or dehydration Whether there is any underlying chronic disease If the host suffers from immobility If they are taking any medication which could disrupt or suppress their immune response General resistance factors (such as mucous membranes, skin, cough reflex etc) that can help defend against infection How can we break the chain of infection? The healthcare environment can expose patients to infection risks that they may not encounter elsewhere. Understanding how infections become established, and how they are transmitted, is essential for effective infection prevention and control. There are opportunities to break or disrupt the chain at any link: Though the rapid and accurate diagnosis of an infectious disease. The prompt treatment of infected patients. The safe disposal of waste. The sterilization and disinfection of medical equipment or the implementation of an environmental decontamination strategy. Answer the following questions Q1- Define chain of infection. Q2- Identify six links of chain of infection. Q3- Describe types of reservoir Q4- How to break chain of infection? 9 Table of content  Health care-associated infections (HCAIs) Definition They are infections that occur while receiving health care, developed in a hospital or other health care facility that first appear 48 hours or more after hospital admission, or within 30 days after having received health care. An infection acquired in hospital by a patient who was admitted for a reason other than that infection. An infection occurring in a patient in a hospital or a health care facility in whom the infection was not present or incubating at the time of admission. Common causing organisms and diseases 10 Table of content I. Bacterial infections: Acinetobacter: Outbreaks of Acinetobacter infections typically occur in intensive care units and healthcare settings housing very ill patients. Burkholderia cepacia: are often resistant to common antibiotics. It is a known cause of infections in hospitalized patients. Clostridioides difficile is a bacterium that causes diarrhea and an inflammation of the colon called colitis. Overuse of antibiotics is the most important risk for getting C. diff. Gram-negative bacteria as Klebsiella and E. coli: cause infections including pneumonia, bloodstream infections, wound or surgical site infections, and meningitis in healthcare settings. Carbapenem-resistant enterobacteria: are an order of germs that are difficult to treat because they have high levels of resistance to antibiotics. Klebsiella species and Escherichia coli (E. coli) are examples. ESBL-producing Enterobacteria: can cause infections both in healthcare settings and outside of healthcare, in communities. Examples include Escherichia coli (E. coli) and Klebsiella. Pseudomonas aeruginosa: Serious Pseudomonas infections usually occur in people in the hospital and/or with weakened immune systems. Staphylococcus aureus: is a bacterium commonly found on the skin and in the nose of about 30% of individuals. Most of the time, staph does not cause any harm. These infections can look like pimples, boils, or other skin conditions and most are able to be treated. Methicillin-resistant Staphylococcus aureus (MRSA): In the community, most MRSA infections are skin infections. More severe or potentially life- 11 Table of content  threatening MRSA infections occur most frequently among patients in Healthcare Settings. Vancomycin intermediate Staphylococcus aureus and vancomycin- resistant Staphylococcus aureus are specific staph bacteria that have developed resistance to the antimicrobial agent vancomycin. Vancomycin resistant Enterococci (VRE) are specific types of antimicrobial-resistant bacteria that are resistant to vancomycin, the drug often used to treat infections caused by enterococci. Tuberculosis (T.B) is caused by a bacterium called Mycobacterium tuberculosis. Cases of multidrug-resistant tuberculosis (MDR-TB), and extensively drug-resistant tuberculosis (XDR-TB), have been recognized and are more difficult to treat. Nontuberculous Mycobacteria (NTM) are mycobacteria other than M. tuberculosis (the cause of tuberculosis) and M. leprae (the cause of leprosy). II. Fungal infections: Candida auris: causes severe illness in hospitalized patients. This yeast often does not respond to commonly used antifungal drugs, making infections difficult to treat. III. Viral infections: Hepatitis The most common types are hepatitis A, hepatitis B, and hepatitis C. Outbreaks have occurred in outpatient settings, hemodialysis units, long- term care facilities, and hospitals. Human Immunodeficiency Virus (HIV/AIDS) is the virus that can lead to acquired immune deficiency syndrome (AIDS). Transmission of HIV to patients while in Healthcare Settings is rare. Most exposures do not result in infection. 12 Table of content  Noroviruses are a group of viruses that cause gastroenteritis and cause outbreaks in hospitals. Influenza is primarily a community-based infection that is transmitted in households and community settings however, influenza prevention measures should be implemented in all healthcare settings. TYPES of HCAIs: 13 Table of content 14 Table of content How do health associated diseases spread? Depending on the type of infection, there are many ways that infectious diseases can spread. Fortunately, in most cases, there are simple ways to prevent infection. Your mouth, your nose and cuts in your skin are common places for pathogens to enter your body. Diseases can spread: From person to person when you cough or sneeze. In some cases, droplets from coughing or sneezing can linger in the air. From close contact with another person, like kissing or oral, anal or vaginal sex. By sharing utensils or cups with other people. 15 Table of content  On surfaces like doorknobs, phones and countertops. Through contact with poop from a person or animal with an infectious disease. Through bug (mosquito or tick) or animal bites. From contaminated or improperly prepared food or water. From working with contaminated soil or sand (like gardening). From a pregnant person to their unborn baby. From blood transfusions, organ/tissue transplants or other medical procedures. DIAGNOSIS AND TESTS 16 Table of content  1- Samples for Testing A sample is taken from an area of the person's body likely to contain the microorganism suspected of causing the infection. Samples may include: Blood Sputum Urine Stool Tissue Cerebrospinal fluid Mucus from the nose, throat, or genital area 2- Staining and Examination Using a Microscope For bacteria, Bacteria are classified as follows: Gram-positive (they look purple) Gram-negative (they look red) 3- Culture of Microorganisms Many samples contain too few microorganisms to be seen using a microscope or to be identified using other tests. Thus, doctors usually try to grow the microorganism in a laboratory (called culture) until there are enough to identify. 4- Testing of a Microorganism's Susceptibility and Sensitivity to Antimicrobial Drugs Microorganisms are constantly developing resistance to drugs that were previously effective. Thus, susceptibility testing is done to determine how effective various antimicrobial drugs are against the specific microorganism 17 Table of content infecting the person. This testing helps doctors determine which drug to use for a particular person's infection. 5- Antigen and Antibody tests Antigen tests detect the presence of a microorganism directly to diagnose an infection quickly, without waiting for a person to produce antibodies in response. Antibody tests are usually done on a sample of the infected person’s blood. It typically takes several days to produce the antibody. 6. Tests That Detect Genetic Material in Microorganisms Nucleic acid–based tests Most nucleic acid–based tests are designed to identify the presence of a microorganism (called qualitative testing), Or tests that can measure how much of the microorganism's genetic material is present (called quantitative testing). 7. Other Tests: Tests that identify certain other unique characteristics of microorganisms: Non-nucleic acid–based identification tests For example, tests can be done to identify the following: Cultural characters: The substances that the microorganism can grow in or grows best in when it is cultured. Enzymes produced by the microorganism (which help the microorganism infect cells or spread through tissues faster) Other substances (such as proteins and fatty acids) that help identify it. 18 Table of content  8. Getting imaging (X-rays, CT scans or MRIs) of affected parts of body. Treatment: Bacterial infections can be treated with antibiotics according to antibiotic sensitivity test results. You can manage most viral infections with over-the counter medications for symptoms. Certain viral infections have special medications to treat them, like antiretroviral therapy for HIV. Fungal infections can be treated with antifungal medications, like fluconazole and clotrimazole. 19 Table of content Chapter (2): Standard Precautions for Infection Control Intended learning outcomes (ILOS) To define principals of infection control Definition A group of infection control practices uses to prevent disease transmission especially by contact applied to symptomatizing or non symptomatizing individual. Components: 1) Hand hygiene 2) Personal protective equipment 3) Aseptic technique 4) Sharp safety 5) Safe injection practices 6) Sterilization and disinfection of patient care equipment 7) Respiratory hygiene /Cough Etiquette 8) Waste disposal 9) Environmental Infection Prevention and Control 20 Table of content  1- Hand hygiene is the most important measure to prevent the spread of infections among patients and HCWs. Types of hand hygiene: A. handwashing with plain (nonantimicrobial) soap and water); B. antiseptic hand wash (soap containing antiseptic agents and water); C. antiseptic hand rub (waterless antiseptic product, most often alcohol-based, rubbed on all surfaces of hands); or 21 Table of content  D. surgical hand antisepsis (antiseptic hand wash or antiseptic hand rub performed preoperatively by surgical personnel to eliminate transient hand flora and reduce resident hand flora). 2- Personal protective equipment: [ PPE] ▪ Wearable equipment used to protect person during deals with patient or its towels or secretions, or body fluids. ▪ Choice of PPE depends on the type of infection between patient and health care worker and type of disease transmission. ▪ E.g., gloves, gown, surgical mask, goggles face shield, eye protector glasses. ▪ Disposable PPE must be discarded in biohazard bags. 3-Needle stick and sharps injury prevention to avoid blood borne pathogens transmission by: ▪ Used needle should be discarded immediately and not recapped, or cut, removed from syringe. ▪ Any needles or sharps should be places in a leak proof puncture resistant container. ▪ The container to be filed to 2/3 only not more than discarded as biohazard label. 4-Cleaning and disinfection ▪ Removal of dirt, organic matter. ▪ Use detergent, disinfection. ▪ Allow air to dry the area or item. 5- Respiratory hygiene To avoid respiratory secretions spread and transmission by: i. Implement measures to contain respiratory secretions in patients and accompanying individuals who have signs and symptoms of a respiratory infection, beginning at point of entry to the facility and continuing throughout the visit. 22 Table of content  a. Post signs at entrances with instructions to patients with symptoms of respiratory infection to— Cover their mouths/noses when coughing or sneezing. Use and dispose of tissues. Perform hand hygiene after hands have been in contact with respiratory secretions. b. Provide tissues and no-touch receptacles for disposal of tissues. c. Provide resources for performing hand hygiene in or near waiting areas. d. Offer masks to coughing patients and other symptomatic persons when they enter the dental setting. e. Provide space and encourage persons with symptoms of respiratory infections to sit as far away from others as possible. If available, facilities may wish to place these patients in a separate area while waiting for care. ii. Educate DHCP on the importance of infection prevention measures to contain respiratory secretions to prevent the spread of respiratory pathogens when examining and caring for patients with signs and symptoms of a respiratory infection. 23 Table of content 6- Waste disposal ▪ Safety boxes resistant for puncture and leak are used then when filled to 2/3 they are transported after closing and labeling as biohazard material to be discarded. ▪ Other disposable PPE, body fluid polluted items are discarded in biohazard bags resistant to leaks and puncture and labeled to be discarded. 7- Safe injection practice To avoid HBV, HCV transmission and other blood borne disease by: ▪ Use new needle and syringe in every medication vial. ▪ New needle and syringe for every patient. ▪ Use a medication vial for one patient only if possible. 24 Table of content  ▪ Don’t use the same syringes between patients even you changed the needle. ▪ Don’t use the same syringes used to infuse medication into an IV tubing port for anther patients. ▪ Hand hygiene during injection and medication preparation. ▪ Skin at site of injection is rubbed by antiseptic. ▪ Preparation of medicine in a clean area. ▪ Medication vials septum are disinfected before use. ▪ Wear disposal gloves during injection. ▪ Needles, syringes are discarded into sharp containers as biohazard. Answer the following questions. Q1-Give an account on hand hygiene. Q2-Give an account on safe injection practice. 25 Table of content Chapter (3): Transmission-Based Precautions Refers to actions (precautions) implemented in addition to standard precautions. Based on the mode of transmission of the disease (Contact, Droplet, Airborne). Aims at Isolation of the pathogen in form of patient isolation to minimize Morbidity and Mortality. Applied in addition to Standard precautions and Not instead of them. TBPs are not required for patients with bloodborne viruses, such as HIV, hepatitis B virus or hepatitis C virus. 1. Contact precautions: Defined as direct or indirect contact with a patient and/or his or her environment including person's room or objects in contact with the person, that has an infection with an organism transmitted fecal-orally, such as Clostridium difficile, or wound and skin infections, or multi-drug resistant bacteria. Multi-drug resistant microorganisms (MDRO’s) [VRE, MRSA, ESBL: colonized or infected. RSV infection in infants, young children and immunocompromised patients Clostridium defficile enterocolitis 26 Table of content  Diarrhea in children (HAV, Norovirus) Viral conjunctivitis (Adenovirus) Scabies Disseminated Herpes Simplex E.Coli 0175 Contact precautions consist of: Ensure appropriate patient placement in a single patient space or room if available. Cohorting patients with the same organism if not possible. Use personal protective equipment (PPE) appropriately, including gloves and gown. Wear a gown and gloves for all interactions that may involve contact with the patient or the patient’s environment. Donning PPE upon room entry and properly discarding before exiting the patient room is done to contain pathogens. Limit transport and movement of patients outside of the room to medically necessary purposes. When transport or movement is necessary, cover or contain the infected or colonized areas of the patient’s body. Remove and dispose of contaminated PPE and perform hand hygiene prior to transporting patients on Contact Precautions. Don clean PPE to handle the patient at the transport location. Use disposable or dedicated patient-care equipment (e.g., blood pressure cuffs). If common use of equipment for multiple patients is unavoidable, clean and disinfect such equipment before use on another patient. 27 Table of content  Prioritize cleaning and disinfection of the rooms of patients on contact precautions ensuring rooms are frequently cleaned and disinfected. 1. Droplet precautions: Droplet precautions are necessary when a patient infected is within three to six feet of the patient. Infections are transmittable through air droplets by coughing, sneezing, talking, and close contact with an infected patient's breathing. Droplets are about 30 to 50 micrometers in size. Meningococcal meningitis MRSA induced Pneumonia Pertussis German measles Influenza type A or B pneumonia, epiglottis and sepsis Streptococcal (group A) pharyngitis Scarlet fever in infants and young children Mumps MERS-CoV Droplet precautions consist of: Source control: put a mask on the patient. Ensure appropriate patient placement in a single room if possible. In acute care hospitals, if single rooms are not available, utilize the 28 Table of content  recommendations for alternative patient placement considerations in the Guideline for Isolation Precautions. Use personal protective equipment (PPE) appropriately. Don mask upon entry into the patient room or patient space. If a patient who is being cared for under droplet precautions requires an aerosol generating procedure (AGP), this procedure should be undertaken in a dedicated treatment room away from other patients. If aerosol generating-procedures are anticipated, a P2/N95 mask should be worn by attending HWs. Limit transport and movement of patients outside of the room to medically necessary purposes. If transport or movement outside of the room is necessary, instruct patient to wear a mask and follow Respiratory Hygiene/Cough Etiquette. 2. Airborne precautions: Airborne precautions are required whenever entering a patient's room or environment who has been diagnosed with or is being tested for with high suspicion of anthrax, tuberculosis, measles, chickenpox, or disseminated herpes zoster or other pathogens that can be transmitted through airflow that are 5 micrometers or smaller in size and remains in the environment for long periods of time. TB Measles Varicella Airborne precautions consist of: Source control: put a mask on the patient. 29 Table of content  Ensure appropriate patient placement in an airborne infection isolation room (AIIR) constructed according to the Guideline for Isolation Precautions. In settings where Airborne Precautions cannot be implemented due to limited engineering resources, masking the patient and placing the patient in a private room with the door closed will reduce the likelihood of airborne transmission until the patient is either transferred to a facility with an AIIR or returned home. Restrict susceptible healthcare personnel from entering the room of patients known or suspected to have measles, chickenpox, disseminated zoster, or smallpox if other immune healthcare personnel are available. Use personal protective equipment (PPE) appropriately, including a fit-tested NIOSH-approved N95 or higher level respirator for healthcare personnel. Limit transport and movement of patients outside of the room to medically necessary purposes. If transport or movement outside an AIIR is necessary, instruct patients to wear a surgical mask, if possible, and observe Respiratory Hygiene/Cough Etiquette. Healthcare personnel transporting patients who are on Airborne Precautions do not need to wear a mask or respirator during transport if the patient is wearing a mask and infectious skin lesions are covered. Immunize susceptible persons as soon as possible following unprotected contact with vaccine-preventable infections (e.g., measles, varicella, or smallpox). 30 Table of content  Chapter (4): Aseptic Technique What is aseptic technique? Bacteria are everywhere, and some are good for us while others are harmful. Bacteria, viruses, and other microorganisms that cause disease are called pathogens. To protect patients from harmful bacteria and other pathogens during medical procedures, healthcare providers use aseptic technique. Aseptic technique means using practices and procedures to prevent contamination from pathogens. It involves applying the strictest rules to minimize the risk of infection. Healthcare workers use aseptic technique in surgery rooms, clinics, outpatient care centers, and other health care settings. What is aseptic technique used for? Following aseptic technique helps prevent the spread of pathogens that cause infection. Healthcare professionals commonly use aseptic technique when they’re: Handling surgery equipment Helping with a baby’s birth by vaginal delivery Handling dialysis catheters Performing dialysis Inserting a chest tube Inserting a urinary catheter Inserting central intravenous (iv) or arterial lines Inserting other draining devices Performing various surgical techniques 31 Table of content Aseptic technique components I. Barriers Barriers protect the patient from the transfer of pathogens from a healthcare worker, from the environment, or from both. Some barriers used in aseptic technique include: sterile gloves sterile gowns masks for the patient and healthcare provider sterile drapes Sterile barriers are those that have not touched a contaminated surface. They’re specially packaged and cleaned items. Healthcare workers put them on or use them in specific ways that minimize exposure to germs. II. Patient and Equipment Preparation Healthcare providers also use sterile equipment and sterile instruments. To further protect the patient, they apply cleansing and bacteria-killing preparations to the patient’s skin before a procedure. III. Environmental controls: Maintaining a sterile environment requires keeping doors closed during an operation. Only necessary health personnel should be at the procedure. The more people present, the more opportunities for harmful bacteria to cause contamination. IV. Contact guidelines Once healthcare providers have on sterile barriers, they should only touch other sterile items. They should avoid touching non-sterile items at all costs. 32 Table of content Example: A common procedure that carries a risk for infection is inserting a urinary catheter. These catheters drain urine from the bladder and are associated with catheter-associated urinary tract infections (CAUTIs). When healthcare providers insert a catheter, they demonstrate all four aseptic techniques in action: Barriers: They wear sterile gloves. Patient and equipment preparation: They open sterile packaging that contains the sterile catheter. They prepare the patient’s skin with a special solution. Environmental controls: Only one or two providers and the patient are in the room. Contact guidelines: Healthcare providers take great care not to touch any non- sterile surface with the hand that advances the catheter into the patient’s urethra. If even one part of the aseptic technique is missed during catheter insertion, the patient can easily get an infection. Clean technique Keeping the environment as clean as possible is always important in preventing infections. However, some situations call for aseptic technique while others call for clean techniques. Examples of clean techniques include washing hands and putting on clean gloves when needed. Healthcare providers keep a patient’s surroundings as clean as possible, but they aren’t using sterile items or aseptic technique. Healthcare professionals commonly use clean techniques when they’re: Giving an injection Emptying a urinary catheter drainage bag 33 Table of content  Giving a bed bath Inserting a peripheral iv (an iv in a smaller vein) Removing a peripheral iv Removing a urinary catheter Aseptic technique benefits Whenever your skin is opened, you’re vulnerable to infection. That’s why it’s critical for you to get prompt treatment for burns and wounds. Even intentional cuts during surgery put you at risk for infection. The way healthcare providers use aseptic techniques before, during, and after your procedure help protect you from infection. When you need surgery or other procedures that require aseptic technique, you’re already vulnerable to infections. You need your immune system to be at its strongest to heal. You have a better chance of a recovery if you don’t have to fight off an infection. Aseptic technique outcome The outcome of aseptic technique depends on whether all healthcare professionals thoroughly follow all procedures. According to the Journal of the American Medical Association (JAMA) Internal Medicine 50% of HAIs are preventable. Healthcare professionals are responsible for following clean and aseptic techniques. If you notice that someone fails to wash hands or sterilize equipment, speak up. Doing so may save you or a loved one from potentially fatal infections. 34 Table of content  Chapter (5): Waste Management Hospital waste are the waste produced in the course of health care activities during treating, diagnosing, and immunizing Human being or animals or while doing Study/Research activities. Improper handling of healthcare waste results in exposure of: 1. Medical personnel (Doctors, nurses, auxiliaries) 2. Those involved in dealing with healthcare waste (Porters, laundries, waste handling and transporting). 3. The whole community 4. Damage to the environment (from pollution of water, air, and food) 5. Failure to properly dispose of waste provides an opportunity for some community members to collect disposable medical equipment (especially syringes) that must be disposed and resold, reused again without sterilization, which leads to the spread of a large proportion of diseases. 35 Table of content Types of medical waste: 75-90% Non-Hazardous/General Waste 10-15% -Hazardous In various facilities, infectious medical waste might have different names such as : Infectious waste. Boihazardous waste. Potentially infectious waste. Regulated medical waste. Types of medical waste: 1. General Waste: No risk to human health eg: office paper, wrapper, kitchen waste, general sweeping etc. 2. Pathological Waste Human Tissue or fluid eg: body parts, blood, body fluids etc. 36 Table of content 3. Sharps Sharp waste eg: Needle, scaples, knives, blades etc. 4. Infectious waste Which may transmit bacterial, viral or parasitic disease to human being, waste suspected to contain pathogen eg: laboratory culture, tissues (swabs)bandage etc. 5. Chemical waste eg: Laboratory reagent, disinfectants, Film Developer 6. Radio-active waste eg: unused liquid from radiotherapy or lab research 7. Pharmacutical Waste Expired outdated drugs /chemicals 8. Pressurized container Gas cylinder, aerosal cans etc 9. Genotoxic Waste: Waste Containing Cytotoxic Drugs (often Used in Cancer Therapy) Associated Diseases: VIRUSES: HIV, Hepatitis B, Hepatitis A,C, Arboviruses, Enteroviruses, Herpes Virus, Dengue, Japanese encephalitis, Ocular infection, Genital Infection can be transmitted through Infected needles, body Fluids, Human excreta, Blood, body fluids, Eye secretion, genital Secretion BACTERIA: Salmonella typhi, Vibrio cholerae, Clostridium Tetani, Pseudomonas, Streptococcus, Typhoid, Cholera, Tetanus Wound infections, septicemia, rheumatic fever, endocarditis, skin and soft tissue infections can be transmitted through Human excreta and body fluid in landfills and hospital wards, Sharps such as needles, surgical blades in hospital waste. PARASITES: Wucheraria Bancrofti, Plasmodium, Cutaneous leishmaniasis, Filariasis, Kala Azar, Malaria can be transmitted through Human excreta, blood and body fluids in poorly managed sewage system. 37 Table of content  I. Sorting: Sorting is separating waste by type (e.g., infectious waste, pharmaceutical waste) into color coded bags at the place where it is generated. should be at the point of origin by the individuals most knowledgeable about the waste's origin and its hazard potential The waste should be placed into appropriate designated containers. Most errors in the medical waste management system occur at the segregation point and involve all associated occupational subgroups. II. Handling Handling is collecting and transporting waste within the facility. As a rule [Handle as little as possible]. Staff involved in handling should be vaccinated against HBV& tetanus. Housekeepers should wear heavy utility gloves and eye protection during cleaning of the containers. 38 Table of content  Use proper packaging for protection and proper handling, storage, and treatment or disposal of the waste. Use colored plastic bags to help distinguish between general and medical waste containers; 1. Red bags are used for infectious and pathologic waste. 2. Yellow bags are used for radioactive waste that is to be dealt with by atomic energy institutions. 3. Black bags are for general waste that is to be disposed with the normal general waste and is to be transferred by the municipals. Plastic bags Should be impervious, tear resistant. keep separate containers in convenient places wherever both general and medical waste are generated; Place sharps containers in convenient places to minimize the distance that staff need to carry sharps; Sharps containers should be puncture-resistant, leak proof on the sides and bottom, and closable. containers should be discarded when they are three quarters full or at least once per day; sealed, lifted by the top. - should not: Compressed (to avoid rupture), Clasped to body Hands should not be placed under. Never put hands into a container that holds medical waste; 39 Table of content  Do not empty medical waste into open carts. III. Transport of medical waste There are three types of medical-waste transport: 1. Collection from the immediate generating area and transport to the temporary storage area on the generating unit. 2. Transport from the temporary storage area on the generating unit to the long term central collection and storage area. 3. Transport from the facility to a treatment or disposal site. There should be separate corridor and lift in hospital to carry and transport waste. General waste are deposited at municipal dumps. Waste for autoclaving and incineration are dumped at separate site for external trasport (should have separate coloured plastic bag for these waste) Transportation should be done in sealed container/sanitation supervisor should ensure for leakage. IV. Interim storage: Interim storage is storing waste within the facility until it can be transported for final disposal. Waste should not be stored in the generation area for more than a period of 4-6 hours. 40 Table of content  It is responsibility of paramedic/sanitation staff to check for segregation. Waste collected in various areas should be trasported for disposal/Treatment. V. Treatment & Disposal General waste should be dumped at municipal dumping site. Sanitation officer should be responsible for proper coordination between municipal and hospital. Use of label/symbole is useful in identifying waste for treatment.eg: Risk of corrosion, Danger of Infection, Toxic hazards, Glass Hazards, Radioactive materials etc. LABEL FOR BIO-MEDICAL WASTE CONTAINERS/BAG Treatment technologies 1.Incineration 2.Chemical Disinfection 3.Wet and dry thermal treatment 4.Microwave irradiation 5.Land disposal 6.Inertization Final disposal Solid waste: A. Open Dumps: risk for public health B. Sanitary landfills: designed and constructed to prevent contamination of soil, surface, ground water and direct contact with public. 41 Table of content  Liquid medical waste can be poured down a sink, drain, and flushable toilet. If none of these are available, liquid medical waste should be buried in a pit. avoid splashing the waste on yourself, on others or on surfaces. After disposal rinse the sink, drain, or toilet to remove residual waste, being careful to avoid splashing. Decontaminate the container that held the liquid medical waste by filling it with a 0.5% chlorine solution and letting it sit for 10 minutes before washing. 42 Table of content 43 Table of content  Chapter (6): Needle stick injury A needle stick injury is the penetration of the skin by a hypodermic needle or other sharp object that has been in contact with blood, tissue or other body fluids before the exposure. These injuries can lead to transmission of blood-borne diseases, placing those exposed at increased risk of infection from disease-causing pathogens, such as the hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). The most exposed group is healthcare workers and laboratory personnel worldwide, Various other occupations are also at increased risk of needlestick injury, including laborers, tattoo artists, and agricultural workers. Psychological effects The psychological effects of occupational needlestick injuries can include health anxiety, anxiety about disclosure or transmission to a sexual partner, trauma- related emotions, and depression. A minority of people affected by needlestick injuries may have lasting psychological effects, including post-traumatic stress disorder. Prevention The prevention of needlestick injuries should focus on those health care workers that are most at risk. The first one is the use of tools that have been changed so that they are less likely to lead to a sharps injury such as blunt or taper-point surgery needles and safety engineered scalpels. Needleless connectors (NCs) were 44 Table of content  introduced in the 1990s to reduce the risk of health care worker needlestick injuries. The second is to start using safe working practices such as the hands-free technique. The third line of prevention is increased personal protective equipment such as the use of two pairs of gloves. To achieve better implementation, legislation, education and training are necessary among all health care workers at risk. Sharp-tipped needles cause 51–77% of surgical needlestick injuries. The American College of Surgeons (ACS) and the Food and Drug Administration (FDA) have endorsed the adoption of blunt-tip suture needles for suturing fascia and muscle. Gloves can also provide better protection against injuries from tapered-tip as opposed to sharp-tipped needles. Studies showed that the use of two pairs of gloves (double gloving) can significantly reduce the risk of needle stick injury in surgical staff. Education with training for at-risk healthcare workers can reduce their risk of needlestick injuries. Treatment After a needlestick injury, certain procedures can minimize the risk of infection. Lab tests of the recipient should be obtained for baseline studies, including HIV, acute hepatitis panel (HAV IgM, HBsAg, HB core IgM, HCV) and for immunized individuals, HB surface antibody. Unless already known, the infectious status of the source needs to be determined. 45 Table of content Unless the source is known to be negative for HBV, HCV, and HIV, post-exposure prophylaxis (PEP) should be initiated, ideally within one hour of the injury. 46 Table of content  Chapter (7): Bloodborne Pathogens What Are Bloodborne Pathogens? Bloodborne pathogens (BBPs): are infectious microorganisms in human blood that can cause disease in humans. These pathogens include, but are not limited to, hepatitis B (HBV), hepatitis C (HCV) and human immunodeficiency virus (HIV). The list of professions that should go through BBP training includes: Doctors, nurses, and other direct patient care providers Paramedics, and other first responders Medical laboratory teams and researchers Nursing home, and home health care providers Dentists, hygienists, and dental assistants Janitorial, laundry, and housekeeping teams Blood and tissue bank staff and blood drive volunteers Medical equipment technicians Examples of Bloodborne Pathogens 1- Hepatitis B Hepatitis B, caused by the Hepatitis B Virus (HBV), is one of two types of bloodborne hepatitis. Hepato- refers to the liver, and -itis refers to an inflammatory condition. Thus, hepatitis is an inflammation of the liver. Hepatitis B comes in two forms: acute, in which infection lasts up to six months before complete recovery, and chronic, in which the infection lingers for over six 47 Table of content months. An HBV infection can be a life-long struggle for people with a compromised immune system. The symptoms of hepatitis B include: joint pain abdominal discomfort nausea vomiting weakness fatigue a decrease in appetite and/or weight loss fever dark-colored urine jaundice If the condition is chronic, long-term inflammation and damage can lead to liver cancer, liver failure, or cirrhosis. Transmission Transmission of hepatitis B virus results from exposure to infectious blood or body fluids containing blood. HBV is 50 to 100 times more infectious than human immunodeficiency virus (HIV). HBV can be transmitted through several routes of infection. In vertical transmission, HBV is passed from mother to child during childbirth. (Without intervention, a mother who is positive for HBsAg has a 20% risk of passing the 48 Table of content infection to her offspring at the time of birth. This risk is as high as 90% if the mother is also positive for HBeAg) Adult horizontal transmission is known to occur through sexual contact, blood transfusions and transfusion with other human blood products, re-use of contaminated needles and syringes. The hepatitis B virus can survive outside the body for at least 7 days. During this time, the virus can still cause infection if it enters the body of a person who is not protected by the vaccine. The incubation period of the hepatitis B virus ranges from 30 to 180 days. The virus may be detected within 30 to 60 days after infection and can persist and develop into chronic hepatitis B, especially when transmitted in infancy or childhood. Prevention Hepatitis B virus Vaccine Vaccines for the prevention of hepatitis B have been routinely recommended for babies since 1991 in the United States. The first dose is generally recommended within a day of birth. The hepatitis B vaccine was the first vaccine capable of preventing cancer, specifically liver cancer. Most vaccines are given in three doses over a course of days. A protective response to the vaccine is defined as an anti-HBs antibody concentration of at least 10 mIU/ml in the recipient's serum. For newborns of HBsAg-positive mothers: hepatitis B vaccine alone, hepatitis B immunoglobulin alone, or the combination of vaccine plus hepatitis B 49 Table of content immunoglobulin, all prevent hepatitis B occurrence. Furthermore, the combination of vaccine plus hepatitis B immunoglobulin is superior to vaccine alone. This combination prevents HBV transmission around the time of birth in 86% to 99% of cases. All those with a risk of exposure to body fluids such as blood should be vaccinated, if not already. Testing to verify effective immunization is recommended and further doses of vaccine are given to those who are not sufficiently immunized. Both types of the hepatitis B vaccine, the plasma-derived vaccine (PDV) and recombinant vaccine (RV) are of similar effectiveness in preventing the infection in both healthcare workers and chronic kidney failure groups. Treatment Although none of the available medications can clear the infection, they can stop the virus from replicating, thus minimizing liver damage. As of 2018, there are eight medications licensed for the treatment of hepatitis B infection in the United States. 2- Hepatitis C Hepatitis C is the other bloodborne type of liver inflammation, caused by the Hepatitis C Virus (HCV). Like Hepatitis B, it’s an acute disease that can also become chronic. There’s no vaccination to prevent hepatitis C, but due to expanding research, there are effective treatments available. Known as direct-acting antivirals, these drugs 50 Table of content can help people overcome the infection in as few as twelve weeks. Some people will recover completely while others may deal with a lifelong infection. Transmission The hepatitis C virus is a bloodborne virus. It is commonly transmitted through: the reuse or inadequate sterilization of medical equipment, especially syringes and needles in healthcare settings. the transfusion of unscreened blood and blood products. injecting drug use through the sharing of injection equipment. Hepatitis C is not spread through breast milk, food, water, or casual contact such as sharing food or drinks with an infected person. Symptoms The incubation period for hepatitis C ranges from 2 weeks to 6 months. Following initial infection, approximately 80% of people do not exhibit any symptoms. Those who are acutely symptomatic may exhibit fever, fatigue, decreased appetite, nausea, vomiting, abdominal pain, dark urine, pale feces, joint pain, and jaundice (yellowing of skin and the whites of the eyes). Prevention There is no effective vaccine against hepatitis C so prevention depends on reducing the risk of exposure to the virus in health care settings and in higher risk populations. Primary prevention interventions recommended by WHO include: 51 Table of content  safe and appropriate use of health care injections; safe handling and disposal of sharps and waste; testing of donated blood for HBV and HCV (as well as HIV and syphilis); training of health personnel 3- HIV and AIDS Human Immunodeficiency Virus (HIV) is the bloodborne pathogen responsible for Acquired Immunodeficiency Syndrome (AIDS). Once infected, a person will test positive for the presence of HIV for the rest of their life. Signs and symptoms The symptoms of HIV vary depending on the stage of infection. Though people living with HIV tend to be most infectious in the first few months after being infected, many are unaware of their status until the later stages. In the first few weeks after initial infection people may experience no symptoms or an influenza- like illness including fever, headache, rash or sore throat. As the infection progressively weakens the immune system, they can develop other signs and symptoms, such as swollen lymph nodes, weight loss, fever, diarrhea and cough. Without treatment, they could also develop severe illnesses such as tuberculosis (TB), cryptococcal meningitis, severe bacterial infections, and cancers such as lymphomas and Kaposi's sarcoma. 52 Table of content Transmission HIV can be transmitted via the exchange of a variety of body fluids from infected people, such as blood, breast milk, semen, and vaginal secretions. HIV can also be transmitted from a mother to her child during pregnancy and delivery. Treatment HIV disease can be managed by treatment regimens composed of a combination of antiretroviral (ARV) drugs. Current antiretroviral therapy (ART) does not cure HIV infection but suppresses viral replication and allows an individual's immune system recovery. 4- Uncommon BBPs Many viral hemorrhagic fevers (VHF) are also the result of bloodborne pathogens. They can be found in some parts of Africa and the Middle East where their non- human host species live. Examples of VHF include Ebola virus disease, Lassa fever, Marburg, and Dengue. How Do You Stop Them From Spreading? The best way to prevent bloodborne pathogens from spreading is to follow universal precautions. In short, this means treating all blood and body fluids as if they were carrying BBPs. Follow standard precautions to help prevent the spread of blood-borne pathogens and other diseases whenever there is a risk of exposure to blood or other bodily fluids. 53 Table of content  Employers of at-risk persons must label hazardous items/areas and offer the hepatitis B vaccine. Substitution: Replace needles without safety devices with ones that have a safety feature built in. Engineering controls: Isolate people from the hazard by providing sharps containers for workers to immediately place needles in after use. Administrative controls: Change the way people work by creating a culture of safety such as avoiding recapping or bending needles that may be contaminated and promptly disposing of used needle devices and other sharps. 54 Table of content  Chapter (8): post-exposure prophylaxis to blood borne pathogens. Exposure Definition: Significant exposure includes contamination by blood or other body fluids or high titers of cell-associated or free virus via 1) percutaneous, e.g., needlestick; 2) per mucosal, e.g., splash in eye or mouth; or 3) cutaneous exposure, e.g., nonintact skin, or involving large amounts of blood or prolonged contact with blood, especially when exposed skin is chapped, abraded, or afflicted with dermatitis. Healthcare workers and other at-risk professionals should be most aware of the methods of accidental exposure. These include: needle sticks punctures from medical sharps or broken glass inhalation of contaminated aerosols, such as when a patient coughs up bloody sputum. accidental blood or body fluids contact with a mucous membrane (eyes, nose, mouth) accidental blood or body fluid contact with damaged or broken skin How long can blood borne pathogens live outside the body? Most blood borne pathogens can live for up to a week outside the body. In fact, dried blood can still transmit hepatitis B and C; a very small amount of contact is all that’s necessary to contract these viruses, even if the source isn’t fresh. 55 Table of content TO PREVENT INFECTION, FOLLOW THESE GUIDELINES: Avoid contact with blood and other body fluids. Use CPR breathing barriers, such as resuscitation masks, when giving ventilations (rescue breaths). Wear disposable gloves whenever providing care, particularly if you may come into contact with blood or body fluids. Also wear protective coverings, such as a mask, eyewear and a gown, if blood or other body fluids can splash. Cover any cuts, scrapes or sores and remove jewelry, including rings, before wearing disposable gloves. Change gloves before providing care to a different patient. Remove disposable gloves without contacting the soiled part of the gloves and dispose of them in a proper container. Thoroughly wash your hands and other areas immediately after providing care. Use alcohol-based hand sanitizer where hand-washing facilities are not available if your hands are not visibly soiled. When practical, wash your hands before providing care. TO REDUCE THE RISK OF EXPOSURE, FOLLOW THESE ENGINEERING AND WORK PRACTICE CONTROLS: Use biohazard bags to dispose of contaminated materials, such as used gloves and bandages. Biohazard warning labels are required on any container holding contaminated materials. Use sharps disposal containers to place sharps items, such as needles. 56 Table of content  Clean and disinfect all equipment and work surfaces soiled by blood or body fluids. IF PERSON EXPOSED, HE SHOULD TAKE THE FOLLOWING STEPS IMMEDIATELY: Wash needlestick injuries, cuts and exposed skin thoroughly with soap and water. If splashed with blood or potentially infectious material around the mouth or nose, flush the area with water. If splashed in or around the eyes, irrigate with clean water, saline or sterile irrigates for 20 minutes. Report the incident to the appropriate person identified in your employer’s exposure control plan immediately. Record the incident by writing down what happened. Include the date, time and circumstances of the exposure; any actions taken after the exposure; and any other information required by your employer. In addition to the following Guidelines for HBV, HBV and HIV post exposure prophylaxis 1- HEPATITIS B EXPOSURE PROTOCOL Check HBsAg status of patient source. l. Unvaccinated employee A. Source known HBsAg (+) - Administer single dose of Hepatitis B Immunoglobulin (HBIG) (0.06 ml/kg body weight within 24 hours, if possible). 57 Table of content -Start Hepatitis B Vaccine series. Note: If exposure is >7 days, do not give HBIG; start Hepatitis B vaccine series if within reasonable proximity of exposure. HBIG’s value >7 days post exposure is unclear. B. Source known, HBsAg (-) 1. Start Hepatitis B vaccine series. C. Source known, HBsAg status undetermined. If High risk that source is HBsAg (+), e.g., patients with high risk of HBV carriage or patients with acute or chronic liver disease (serologically undiagnosed). a. Administer single dose of HBIG. b. Start Hepatitis B vaccine series. D. Source unknown 1. Start Hepatitis B vaccine series; Categorized as “unknown source”. ll. Vaccinated employee A. Source known, HbsAg (+) 1. Employee completed all 3 doses. a. If known responder, no treatment. b. If antibody response unknown, test employee and if adequate, no treatment c. If antibodies inadequate on testing or employee has previously not responded to vaccine, administer single dose of HBIG immediately; (no 58 Table of content  later than 7 days post exposure) and a booster dose of Hepatitis B Vaccine or HBIG x2 1 month apart if employee has failed to respond to at least 4 doses of HBV.¹ 2. Employee completed 1 or 2 doses a. Administer single dose of HBIG immediately and continue on schedule with vaccine series. HBsAb can be tested after 2 doses of HBV. B. Source known, HBsAg (-) 1. No testing or treatment. D. Source unknown 1. If employee has completed series (3 doses), may request testing for HBsAb; otherwise no further testing or treatment; categorized as “unknown source”. 2- HEPATITIS C EXPOSURE PROTOCOL Only if the source individual is an intravenous drug user, haemophiliac or from a high HCV prevalence setting, or where the source is unknown. In such cases, the source should be tested for HCV Ab. If the source is HCV-negative, the exposed individual should be tested at baseline to assess their own HCV status, and no further HCV testing will be necessary in further follow-up. However, where the source is HCV-positive and the exposed individual is HCV- negative at baseline, HCV PCR testing should be performed at 6 weeks and HCV AB at 6 months. 59 Table of content 2- HIV EXPOSURE PROTOCOL Initial HIV testing: Before initiating post exposure prophylaxis (PEP) after potential HIV exposure, persons should be tested for HIV1 and HIV2 antigens and antibodies in the blood using a rapid diagnostic test. PEP should only be started if rapid diagnostic test reveals no HIV infection present or if tests results are not available. However, if HIV infection is already present then PEP should not be started. HIV test should be repeated four to six weeks and three months after exposure. If follow-up laboratory antibody tests reveal HIV infection, HIV treatment specialists should be sought out and PEP should not be discontinued until person is evaluated and treatment plan is established. Treatment In the case of HIV exposure, post-exposure prophylaxis (PEP) is a course of antiretroviral drugs which reduces the risk of seroconversion after events with high risk of exposure to HIV. The CDC recommends PEP for any HIV-negative person who has recently been exposed to HIV for any reason. To be most effective, treatment should begin within an hour of exposure to 48 hour. After 72 hours PEP is much less effective, and may not be effective at all. Prophylactic treatment for HIV typically lasts four weeks. People who received PEP are typically advised to get an antibody test at 6 months post-exposure as well as the standard 3 month test. 60 Table of content  Chapter (9): Disinfection and Sterilization Intended learning outcomes (ILOS) To define disinfection To describe Levels of disinfection To define resistance level of organisms To describe methods of disinfection To identify factors affecting chemical disinfection: To identify test to assess the disinfection Definition: Disinfection: Process by which we can minimize the number of microorganisms except bacterial spores in animate or inanimate surface. Disinfectant: chemical substance to be used to disinfect (Inanimate) surface. Antiseptic: Chemical substance can be used to disinfect (animate) surface. Levels of disinfection: 1) High level: against Many spores after long time exposure. T.B. Wide range virus. Vegetative cells. 2) Intermediate level: against Limited no of spores. T.B. Fungus. Intermediate level virus. 61 Table of content  Vegetative cells. 3) Low level: Vegetative cells Some fungus Some range of virus. Resistance level of organisms 1- Prions. 2- Spores. 3- T.B. 4- Non enveloped viruses. 5- Fungal spores. 6- Vegetative gram –ve bacteria. 7- Fungus. 8- Vegetative gram +ve bacteria. 9- Enveloped virus. Methods of disinfection Disinfection Thermal Chemical 62 Table of content  A) Thermal disinfection It includes Temperature below sterilization level. a. At lower temperature (80°c) - For five minutes. - For materials damaged by boiling. b. Pasteurization of milk. c. Boiling for 20 minutes - For surgical instruments. - Kill T.B, HIV, Hepatitis virus but not spores. d. Steaming at 100°c (koch's steamer) - For (60-90) minutes - For flat non wrapped instruments. e. Heat from sun - Dry linen to expose to ultraviolent rays of sun. f. Ironing - For clothes, linen. coats. B) Chemical disinfection a. Hydrogen peroxide (H2o2) High level. Mechanism: oxidizing agent with release of free radicals interfere with pathogen Not irritant or toxic. Act as antiseptic for wound dressing. Act as disinfection in contact lens and environment. Disadvantages 63 Table of content  a) Not stable by dilation b) Not compatible with zinc, copper, nikl surface due to production of H2O +O2 corrosion b. Peracetic acid High level. Mechanism: oxidizing agent with release of free radicals interfere with pathogen. Active against legionella & biofilm. Act as disinfectant for environment. Disadvantages: a) Skin- eye irritation. b) Not stable by dilution. c) Not compatible with Nikl, Zinc, copper surface. c. H2O2 + peracetic acid High. Mechanism: oxizaing agent with release & free radicals interfere with pathogen. Strong disinfectant for environment. Active against T.B, spores. Disadvantages: a) Skin – eyes irritation. b) Not stable by dilution. c) Not compatible with metallic surface. d. Glutaraldhyde. High level Mechanism: denaturate proteins and DNA by alkylation. 64 Table of content  Disinfection for rubber and lens systems. ( endoscopes) Kill spores. Disadvantages: a) Skin- eye irritation. b) Spontaneous degradation by time. c) Dilution causes instability. d) May affect the lens system by opacity by time. e. Formaldehyde High. Mechanism: denaturant proteins and Nucleic acid by alkylation. Potent disinfection against T.B spores. Cheap. Disadvantage: a) Skin- eye irritation. b) Respiratory system irritation. c) Hepatotoxic. f. Orthophathaldhyde (OPA) High. Mechanism: interfere with protein and amino acid of pathogen. Potent disinfection against spores, prevent their germination. Fast, compatible with optic systems. Non-significant odor. Disadvantages: a) Expensive. b) Staining of skin, clothes, and environmental surfaces. c) Eye irritation. 65 Table of content  d) May cause cancer bladder. g. Alcohol Intermediate. Mechanism: Disturbs lipid of cell membrane of organism and denatures proteins. Act as antiseptic and disinfectant. Against T.B. Disadvantage: a) Cause skin dryness unless adding conditioner b) Not suitable for open wound and mucous membranes c) Not sporicidal. h. Iodophores Intermediate. Mechanism: protein denaturation. Antiseptic. Suitable for skin (not staining) or irritant. Wide range and leave residual effect. Disadvantage: a) Expensive. b) Not for obstetric patients may cause thyroid gland affection. c) Not for environment or instruments. i. Chorine Intermediate. Mechanism: protein denaturation by oxidation Disinfectant for environment. Cheap, safe for food places. 66 Table of content  Strong, broad spectrum. Disadvantages: a) Bleaching material. b) Corrosive with stainless surface. c) Inactivated by organic materials. j. phenolics Intermediate. Mechanism: protein denaturation and cell membrane destruction. Disinfection. Stable. Potent against Gram +ve and Gram -ve organisms. Disadvantages: a) Toxic. b) Not against virus. c) Strong odor respiratory irritation. k. Quaternary ammonium compounds. Low. Mechanism: disturb cell membrane, protein, enzyme denaturation. Cleaning material for skin not environment. Disadvantages: a) Cleaning agent not disinfectant or antiseptic. b) Not for environment or instruments. l. Chlorhexidine Low. Mechanism: damage DNA, disturb cell membrane. 67 Table of content  Cleaning or low antiseptic for skin. Disadvantages: a) Ototoxic. b) Eye irritation. c) Week against (Gram –ve) bacteria. Factors affecting chemical disinfection: a) Microorganism resistance. b) Biofilm formation. c) Load of microorganism. d) Condition of growth. e) Temperature. f) Concentration & volume. g) PH at which material and organism are active h) Potency of material. i) Natural or spontionus degradation of material. j) Inactivation by organic or other disinfectant. Answer the following questions: Q1- Define disinfection Q2- Describe Levels of disinfection Q3- Define resistance level of organisms Q4- Describe methods of disinfection Q5-Identify factors affecting chemical disinfection: 68 Table of content  Sterilization Intended learning outcomes (ILOS) To define sterilization To identify steps of sterilization To describe sterilization of heat sensitive items To describe sterilization of heat stable items To identify cold sterilizer To describe sterilization of culture media To monitoring sterilization To identify methods for transport sterilized items To describe methods for storage of sterilized items Definition: The process which destroys all forms of microbes including spores to reach sterility assurance level (ASL) of (10-6). Steps of sterilization A) Cleaning. B) Sterilization according to type of Instrument. C) Transport. D) Storage. Types of Instrument Heat stable Heat sensitive Heat>120°c Heat