DEFINITION
Microbiology (Greek; mikros = small, bios = life, logos = study of) is the science of living organisms that are visible only under the microscope.
In the second half of the nineteenth century, microbiology was differentiated into general, medical, industrial, agricultural, veterinary, food, soil and plant microbiology.
Medical microbiology has become an intensive science and it is subdivided into:
Bacteriology | = | Science of pathogenic bacteria |
Virology | = | Science of infectious viruses |
Serology | = | The study of reactions between antigen and antibody |
Mycology | = | Study of fungi—pathogenic to man |
Parasitology | = | Study of parasites—protozoa and helminths |
Protozoology | = | Study of pathogenic protozoa |
Helminthology | = | Study of helminths (worms) |
Entomology | = | Study of insects (vectors)—transmitting diseases to man. |
In addition, medical microbiology includes the study of mechanisms of infectious disease and immunity (immunology), the methods of therapy and prophylaxis of infectious diseases. Genetics is the study of heredity and variations.
Nursing microbiology is the application of the knowledge of medical microbiology at the bedside of patients during nursing care. Basic principles of various procedures are drawn from the science of microbiology.
APPLICATION OF MICROBIOLOGY IN HEALTH SCIENCE
Why should the nurse study microbiology?
Application of the basic principles of medical microbiology is essential to the practice of any medical profession. The following are some of the areas in health science where microbiological principles are applied:
- Health: Promotion and betterment of human health. Enhancement of human life expectancy and longevity.
- Conquest of epidemics and fatal infections: Immunization has resulted in the eradication of smallpox, control of plague, diphtheria, tuberculosis, poliomyelitis and measles.
- Child care safe: Upbringing and prevention of infectious diseases of childhood and thus reduce infant mortality.
- Revolutionary influences on the prevention, diagnostic methods, treatment and control of infectious diseases.
- Improved food preservation and safe drinking water for all.
- Effective disposal of sewage and waste.
With microbiology forming the foundation of professional nursing, the nurse has an increasing responsibility to practice and teach hygienic measures both in the care and prevention of diseases.
The study of microbiology helps the nurse in many different ways. Nurse learns how the disease-producing organisms enter into the body, how they are discharged from the body and how they spread from person to person. Nurse will understand the principles of disinfection and effect of drugs on microorganisms. Nurse recognizes the importance of proper collection of specimens for bacteriological examination in 4 the laboratory and understands the meaning of reports received from the laboratory. In addition, nurse understands how sera and vaccines used in the treatment and prevention of diseases are prepared and their effects on the human body.
The modern study of microbiology has developed in stages. Fracastoro of Verona (1546) gave the idea that infection consists of minute particles, which are too small to be seen by the naked eye. He also described the modes of spread of infection by direct contact and by formites.
Antonie van Leeuwenhoek, the father of microscopy (1632—1723) was the first person to see and describe microbes. He was a draper from Delft, Holland, who wanted to observe the weaving of fine cloth. He made the earliest high power microscope consisting of a single magnifying glass held in a metal frame. He was able to produce lenses with 300 to 400 magnification power. With the help of these he observed minute organisms, bacteria and protozoa, which he called ‘animalcules’ from rain water and tartar of teeth, some of which were mobile.
IMPORTANT CONTRIBUTIONS
Louis Pasteur (1822–1895)
French chemist considered as Father of microbiology
- Microbial theory of fermentation.
- Principles and practice of sterilization (steam sterilizer, hot air oven and autoclave).
- Control of diseases of silkworms.
- Development of vaccines against
- Anthrax
- Rabies
- Chicken cholera.
- Discovery of streptococci.
Robert Koch (1843–1910)
German doctor considered as Father of bacteriology
- Discovery and use of solid media in microbiology.
- Discovery of the causative agents of
- Anthrax (1876)
- Tuberculosis (1882)
- Cholera (1883).
- Koch's phenomenon, hypersensitivity phenomenon of Mycobacterium tuberculosis.
- Koch's postulates.
Koch's Postulates
According to Koch's postulates, a microorganism can be accepted as the causative agent of an infectious disease only if the following conditions are satisfied:
- The specific organism should always be found in association with the given disease.
- It should be possible to isolate the organism in pure culture from the lesions of the disease.
- The isolated organism in pure culture, when inoculated into suitable laboratory animals, should produce a similar disease.
- It should be possible to reisolate the organism in pure culture from the lesion produced in the experimental animal.
- An additional criterion introduced subsequently, requires that specific antibodies to the organism should be demonstrable in the serum of the patient. However, it may not be possible to satisfy for all the postulates in every case. An important exception of not fulfilling the Koch's postulates is lepra bacillus.
Koch's Phenomenon
Koch observed that guinea pigs already infected with Mycobacterium tuberculosis respond with an exaggerated inflammatory response when infected with tubercle bacilli or its proteins. This hypersensitivity reaction is known as Koch's phenomenon.
Joseph Lister (1827–1912)
English surgeon considered as Father of antiseptic surgery
Lister was deeply concerned with postoperative sepsis, which took a terrible toll. Postoperative patients were dying like flies after successful surgery. By washing wounds with phenol (carbolic acid) spray and applying protective dressings, he prevented germs from entering the site of operation and thereby reduced postoperative sepsis, mortality and morbidity.
Because carbolic acid is too toxic to the tissues, it was replaced by sterilization techniques and other modern antiseptic approaches, which have revolutionized modern surgery.5
Florence Nightingale (1820–1910)
Florence Nightingale organized hospitals that minimized cross-infections.
Fanny Hesse (1850–1913)
Fanny Hesse was a housewife. She suggested the use of agar as a solidifying material in microbiological media.
CLASSIFICATION OF MICROORGANISMS/MICROBES
- Bacteria.
- Viruses.
- Fungi.
- Protozoa.
- Mycoplasma.
- Rickettsiae.