Introduction to Microbiology: Exploring the Diverse World of Microorganisms, Their Cellular Structures, Metabolic Functions, and Their Critical Roles in Health, Disease, and Environmental Processes"

This content provides the detail notes on Introduction to Microbiology for Nurses in III Semester BSC Nursing students

1. INTRODUCTION TO APPLIED MICROBIOLOGY FOR NURSES Prepared by Ms.Amala Seeli.M Assistant Professor, Chettinad College of Nursing, Chettinad Academy of Research and Education, Chennai 1

2. Unit I Introduction Importance and Relevance to Nursing Concepts and Terminology in Microbiology Principles of Microbiology 1

3. 1.Importance and Relevance to Nursing (5 marks) Microbiology is the study of all living organisms that are too small to be visible with the naked eye. This includes bacteria, archaea, viruses, fungi, prions, protozoa and algae, collectively known as ‘microbes’. Medical microbiology deals with the study of microorganisms responsible for various diseases of low to high intensity, and it can be divided into: Bacteriology, which deals with study of bacteria. Virology, which facilitates study of viruses. Parasitology, which involves unicellular to multicellular parasites. Mycology, that deals with various fungal microorganisms Importance of Microbiology in Nursing Practice Role of a nurse in relation to the condition of the patient, disease stage, diagnosis, treatment module, and hospital environment from a microbiological perspective. The role of a nurse is varied, and it is important for a nurse to multitask intellectually with fundamental knowledge, decisive thinking, and application. Evolving nurses with a conceptual clinical approach towards the following: Asepsis, sterilization, and disinfection Recognition of infection Infection control—pathogenesis and transmission Nosocomial infection Immune system Clinical thought process. 2

4. 1.Importance and Relevance to Nursing Need of Microbiology in Nursing Practice Nurses are involved in managing all aspects of patient’s health and infection control in the hospitals. A nurse must know microbiology to take care of a patient and to protect oneself from pathogenic microorganisms. Nurses utilize concepts of microbiology while giving patient care or doing procedures. To prevent spread of infection Nurses should have knowledge about the mode of spread of infection. Some infections are spread by contact (touch), air (air-borne), droplets (sneezing, coughing), some by eating contaminated food or drink (foodborne), sexual contact (STDs), by arthropod bite (vector born) and others by contaminated blood transfusion, etc. the knowledge would help a nurse to use particular measures to save community and hospital spread of infection. To Maintain Sterile Field A nurse must know procedures used to create and maintain a sterile field in the hospitals and these are based on the knowledge of microbiology. The knowledge of microbiology can further help a nurse to use sterile equipment which are a necessary part of invasive procedures done on patients. The principles of asepsis are based on microbiology. The knowledge of sterilization techniques is mandatory for a nurse. The proper disposal of biomedical waste is equally important. 3

5. 1.Importance and Relevance to Nursing To collect specimens The nurse must recognize the importance of proper collection of specimens to be sent for bacteriological examination to obtain accurate results. For instance, she has to be familiar with the various infectious disease and their route of infection to collect clinical specimen from a proper site like, pustule or blood or stool etc. Immunization A nurse also plays an important role in immunization to control threats of various diseases like diphtheria or MMR etc. So they must have knowledge of various antisera and vaccines used in preventing the dreadful diseases. The immunization schedules and the cold chain used to deliver the vaccines from the production to the administration should be known to a nurse. Knowledge of immunology makes a nurse well-prepared for vaccination and protection of vaccines by using cold chain. Research and Development In the ever-evolving field of healthcare, research is vital for advancements. Microbiology plays a critical role in research and development, aiding nurses in understanding emerging pathogens and innovative treatments. This knowledge contributes to better patient care and healthcare practices. 4

6. 1.Importance and Relevance to Nursing Patient Safety Understanding microbiology principles can help nurses prevent the spread of infections in healthcare settings, ensuring the safety of their patients. The mode of infection transmission is another crucial aspect of microbiology that nurses must understand. For instance, diseases such as tuberculosis can spread through contact, air, droplets, contaminated food and drink, sexual contact, arthropod bites, contaminated blood transfusions, etc. Nurses’ awareness of how pathogens enter and leave the body and spread from person to person helps them to take appropriate measures to prevent the spread of infection. For instance, negative pressure rooms can help patients suffering from tuberculosis. Public Health Microbiology plays a critical role in public health. Nurses can educate patients on the importance of infection prevention and control and advocate for policies and practices that promote public health. Diagnosing and Treating Disease Nurses also use their knowledge of microbiology to diagnose and treat diseases. They collect samples from patients, send them to the laboratory for testing, and interpret the results. Nurses also administer medications, including antibiotics, to treat infections. 5

7. 1.Importance and Relevance to Nursing Preventing the Spread of Infection One of the most important roles of nurses in implementing microbiology is to prevent the spread of infection. Nurses do this by following strict infection prevention and control (IPC) procedures. These procedures include: Handwashing Wearing gloves and other personal protective equipment (PPE) Using sterile technique when handling invasive devices Isolating patients who are infected with contagious diseases Providing Patient Education Nurses also provide patient education about microbiology. They teach patients about the importance of handwashing, how to prevent the spread of infection, and how to take their medications correctly. Nurses also educate patients about the signs and symptoms of infection, so that they can seek medical attention promptly. 6

8. 2.Historical Perspective of Microbiology There were several eminent personalities in the field of Microbiology, whose important contributions have been described below. Aristotle (384-322 BC) – “Father of Biology”. He described living and non-living organisms ( eg : wood, plants, animals etc ). He was the first scientist to study different biological processes like metabolism, temperature regulation, embryogenesis, inheritances Louis Pasteur Louis Pasteur (1822-1895), also known as 'father of microbiology' has made several remarkable contributions. He had proposed the principles of fermentation for the preservation of food He introduced the sterilization techniques and developed steam sterilizer, hot air oven, and autoclave He described the method of pasteurization of milk He contributed to the vaccine development against anthrax, fowl cholera, and rabies He postulated the 'germ theory of disease, which states that disease cannot be caused by bad air, but it is produced by the organisms present in the air Liquid media concept: He used nutrient broth to grow microorganisms He was the founder of the Pasteur Institute, Paris. Joseph Lister Joseph Lister (1867) is considered to be the 'father of antiseptic surgery. He postulated that postoperative infections can greatly be reduced by using disinfectants to sterilize the surgical instruments and to clean the wounds. 7 Louis Pasteur

9. 2.Historical Perspective of Microbiology Robert Koch Robert Koch (1843-1910), made notable contributions to the field of microbiology. His contributions were as follows: He introduced solid media for the culture of bacteria He introduced methods for isolation of bacteria in pure culture He described hanging drop method for testing motility He discovered bacteria such as the anthrax bacilli, tubercle bacilli and cholera bacilli Koch’s Postulates: Robert Koch had postulated that a microorganism can be accepted as the causative agent of an infectious disease only if four criteria are fulfilled. These criteria are as follows: The microorganism should be constantly associated with the lesions of the disease It should be possible to isolate the organism in pure culture from the lesions of the disease 3The same disease must result when the isolated microorganism is inoculated into a suitable laboratory animal It should be possible to re-isolate the organism in pure culture from the lesions produced in the experimental animals. Exceptions to Koch's postulates: There are some bacteria that do not satisfy one or more of the four criteria of Koch's postulates. Mycobacterium leprae and Treponema pallidum cannot be grown in culture; whereas Neisseria gonorrhoeae has no animal model. 8 Robert Koch

10. 2.Historical Perspective of Microbiology Other Important Contributors Antonie van Leeuwenhoek (1676): He was the first scientist who observed bacteria and other microorganisms, using a single- lens microscope constructed by him and he named those small organisms as 'Little animalcules’ Edward Jenner (1796): He, developed the first vaccine of the world, the smallpox vaccine. He used the cowpox virus ( Variolae vaccinae ) to immunize children against smallpox from which the term 'vaccine' has been derived. The same principles are even used today for developing vaccines Paul Ehrlich (1854-1915): He is known as 'father of chemotherapy. He was also the first to report the acid-fast nature of tubercle bacillus Hans Christian Gram (in 1884): He developed a method of staining bacteria which was named as 'Gram stain' to make them more visible and differentiable under a microscope Ernst Ruska: He was the founder of electron microscope (1931)* Alexander Fleming (in 1929): He discovered the most commonly used antibiotic substance of the last century, i.e., penicillin Karry B Mullis: Discovered polymerase chain reaction (PCR) and was awarded Noble Prize in 1993 Ignaz Semmelweis (1846): He introduced the importance of hand hygiene in healthcare facilities. He proposed that improper hand hygiene practice during delivery led to the transmission of infection causing outbreak of puerperal fever. 9 Paul Ehrlich

11. 2.Historical Perspective of Microbiology Francesco Reedi (1626-1697) – reported that maggots/larvae were not formed on the decaying meat when it was covered. John Needham (1713-1781) – supported spontaneous generation theory. Findings included that tiny organisms were found in mutton broth present in the flask even after covering it with a cork. Lazarro spallanzi (1729-1799) – proved that air carried germs into the flask containing meat broth and germs grew in it. He also described that boiled broth did not support the growth of germs on it. Von Plenciz (1762) - hypothesized that each disease is caused by separate living agent/germ 10

12. 3.Concepts and Terminology in Microbiology Important concepts in Microbiology: Sterilization – It is a method of destroying or eradicating all types of microorganisms. Various sterilization methods are used for destroying pathogenic microbes present on working surfaces or medical devices used in patient care. Few sterilization methods are: Dry and moist heat methods, radiation, autoclaving, using chemicals like alcohol, dyes, phenols etc. Pasteurization – It is a procedure in which germs/microbes are killed and shelf life is extended by heating packaged and unpackaged goods (such as milk and fruit juices) at temperatures below 100°C. This method is designed to kill or deactivate microorganisms and enzymes that cause spoilage and decrease disease risk. Taxonomy – It is science used for naming, describing and classification of animals, plants and microorganisms based upon their common characteristics. Taxonomy helps in studying various organisms, their inter-relationship, and their hierarchical position Immunization – the process by which a person's immune system becomes stronger in the presence of an infectious pathogen. Immunization can be passive or active. It is done using various methods and most common method is vaccination. Bio-medical waste management - any waste produced during the diagnosis, treatment, or immunization of humans or animals, or during related research activities, or during the manufacturing or testing of biological substances is called bio-medical waste. Management of such waste is done using specified protocols. Methods used in this process are autoclaving, incineration, radiation etc. Nurses should have the knowledge of segregation, storage, transportation and management methods of biomedical waste produced in hospitals 11

13. 3.Concepts and Terminology in Microbiology Bacteriology – Study of Bacteria Virology –Study of Viruses Mycology – Study of Fungi Parasitology – Study of Parasites Hospital Infection Control – It deals with the study of various control measures to prevent the transmission of healthcare associated infections. Pathogen - a disease causing microbe Host – animal/plant/human in which a microbe can live Parasite - A parasite is a creature that lives on or in its host and feeds on or at the expense of that host. Vector – An organism that does not cause disease but transmits infection by transporting diseases casing agent/germ from one host to another. Carrier - A carrier is a person who carries and can pass on a disease and may or may not show symptoms of the condition. Infection - Invasion and proliferation of microorganisms that are not ordinarily present in the body, such as bacteria, viruses, and parasites.12. Pathogenicity - refers to an organism's ability to cause sickness. Virulence - refers to the extent to which the organism can cause disease/pathology. Toxin - a substance produced by a living organism that is toxic to other living organisms 12

14. 3.Concepts and Terminology in Microbiology Toxicant - a substance which is toxic in nature and produced by man16. Bactericide – a chemical substance used for killing of bacteria. Disinfectant - Any substance used to kill harmful microbes that can cause infection and disease present on non-living items. Antiseptic – chemical substances that inhibit or limit the growth of potentially dangerous microbes on the skin and mucous membranes etc. Vaccine - biological agents that trigger an immune response in response to a specific antigen produced from a pathogen that causes an infectious disease. Fomites - any inanimate object that can transmit disease to a new host when contaminated with or exposed to infectious pathogens 13

15. 4.Principles of Microbiology Principles of microbiology can be applied in our day to day lives like by sanitation, environmental sanitization, food hygiene, safe water supply, cleaning of house hold articles, sterilization of contaminated articles etc. Nurses apply these principles as they work in hospitals where different pathogenic microorganisms thrive. Maintenance of hand hygiene by washing with disinfectant is the basic method used by nurses before and after handling patients, collecting samples from patient’s and importantly attending other patients or people. Disinfection of medical devices (e.g.: thermometers etc.) should be done after use. Sterilization of surgical devices/instruments is critical before and after use. Appropriate preventive methods are followed by nurses while handling patients in order to prevent transmission of infection to self or other patients Handling of bio-waste and maintenance of aseptic conditions are basic principles nurses follow in health care systems. 14