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Introduction to Medical Microbiology. What is Microbiology. Microbiology – study of microorganisms (simple forms of life visible only with a microscope) Microorganisms may be Normal flora Pathogenic. Why is it Important?.
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What is Microbiology • Microbiology – study of microorganisms (simple forms of life visible only with a microscope) • Microorganisms may be • Normal flora • Pathogenic
Why is it Important? • Infection is one of the most important causes of mortality and morbidity in the population. • Approximately 30% of hospital patients are on antibiotics at any one time • 1 in 10 patients acquires an infection whilst in hospital.
Pioneers of Microbiology • Antoni van Leeuwenhoek, (1673) • First observed live microorganisms (animalcules) • Schleiden and Schwann, • Formulated Cell Theory: cells are the fundamental units of life and carry out all the basic functions of living things • Pasteur, and Tyndall, (1861) • Finally disproved spontaneous germination
Pioneers of Microbiology • Louis Pasteur (1822-1895), Chemist • Fermentation (1857) • Pasteurization: heat liquid enough to kill spoilage bacteria (1864) • Vaccine development – rabies • Proposed the germ theory of disease • Director of Pasteur Institute, Paris (1894)
Pioneers of Microbiology • Joseph Lister, UK (1867) • Used phenol (carbolic acid) to disinfect wounds • First aseptic technique in surgery • Robert Koch, DE (1876) • Postulates (1876) • Identified microbes that caused anthrax (1876), tuberculosis (1882) and cholera (1883) • Developed microbiological media & streak plates for pure culture (1881)
The Early Years of Microbiology contributed by discovery of Microscope
Antonie van Leeuwenhoek • First to observe living microbes • his single-lens magnified up to 300X (1632-1723)
History of Microbiology started with 1673-1723, Antoni van Leeuwenhoek (Dutch) described live micro-organisms that he observed in teeth scrapings, rain water, and peppercorn infusions. (Animacules)
The Golden Age of Microbiology 1857-1914 Beginning with Pasteur’s work, discoveries included the relationship between microbes and disease, immunity, and antimicrobial drugs
Spontaneous generation Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter. (flies from manure, etc)
Germ theory of disease Replaces Fate and Sins Many diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc.
Louis Pasteur Laid foundations in Microbiology • He is the father of Medical Microbiology. (1822-1895)
Contributions of Louis Pasteur: • coined the terms “microbiology”, aerobic, anaerobic and Vaccine • Showed microbes caused fermentation & spoilage • Disproved spontaneous generation of micro-organisms. • He invented the processes of pasteurization, fermentation and the development of effective vaccines
Contributions of Louis Pasteur: • Developed aseptic techniques. • demonstrated that anthrax was caused by bacteria. • He developed live attenuated vaccine for the anthrax. • Developed a rabies vaccine.
Robert Koch1843 - 1910 A German scientist • Formulated the Bacteriological techniques • Staining Methods • Discovered the Mycobacterium and Vibrio cholera
Established a sequence of experimental steps to show that a specific microorganisms causes a particular disease. • He demonstrated the role of bacteria in causing disease. • He perfected the technique of isolating bacteria in pure culture
Robert Koch establishes many Principals and postulations • Koch perfected his methods of diagnostics and expanded on the work of others. • Koch invented the method of cultivating bacteria on nutrient mediums, using potatoes as his source of nutrients for bacteria, • and created a medium that could be stored in dishes created by his colleague Petri.
Robert Koch and Postulates • Koch’s work on diseases and diagnostics culminated with the creation of what are now known as Koch’s Postulates. • Koch’s Postulates are the 4 steps necessary to confirm if a suspected pathogen is indeed the cause of a disease.
Koch's postulates the pathogen must be present in every case of the disease the pathogen must be isolated from the diseased host & grown in pure culture the specific disease must be reproduced when a pure culture of the pathogen is inoculated into a healthy susceptible host the pathogen must be recoverable from the experimentally infected host
Additional criteria: specific antibodies to the bacterium should be demonstrable in the serum of the patients suffering from the disease. Dr.T.V.Rao MD
Exceptions to Koch’s Postulates • Microorganisms that are unable to be cultured on artificial media • (example: Treponemapallidum) • 2 or more organism work in synergy to cause a disease. • Symptoms and diseases can be caused by any one of several microbes.
Joseph Lister • Joseph Lister, was a British surgeon and a pioneer of antiseptic surgery. • By applying Louis Pasteur's advances in microbiology, he promoted the idea of sterile surgery while working at the Glasgow Royal Infirmary.
Joseph Lister He instructed surgeons under his responsibility • to wear clean gloves • wash their hands before and after operations with 5% carbolic acid solutions. • Instruments were also washed in the same solution and assistants sprayed the solution in the operating theatre.
John Tyndall (1820 - 1893) • He discovered highly resistant bacterial structure, later known as endospore. • Prolonged boiling or intermittent heating was necessary to kill these spores, to make the infusion completely sterilized, a process known as Tyndallisation.
Edward Jenner (1749-1823) • First to prevent small pox. • He discovered the technique of vaccination. Alexander Flemming • He discovered the penicillin from penicilliumnotatum that destroy several pathogenic bacteria.
Paul Erlich(1920) He discovered the treatment of syphilis by using arsenic He Studied toxins and antitoxins in quantitative terms & laid foundation of biological standardization.
IMPORTANT DISCOVERIES: Bacteria: • Hansen (1874) – Leprosy bacillus • Neisser (1879) – Gonococcus • Ogston(1881) – Staphylococcus • Loeffler(1884) – Diphtheria bacillus • RouxandYersin – Diphtheria toxin
IMPORTANT DISCOVERIES: Viruses: • Beijerinck(1898) - Coined the term Virus for filterable infectious agents. • Pasteurdeveloped Rabies vaccine. • GoodPasteur - Cultivation of viruses on chick embryos. • CharlesChamberland,one of Pasteur’s associates constructed a porcelain bacterial filter. • Twortandd’Herelle-Bacteriophages. • EdwardJenner- Vaccination for Smallpox.