Introduction to Microbiology

• What is microbiology

  • The study of microorganisms - microbes (minute living organisms – animal or plant), these may be

  Bacteria ( Bacteriology )

  Viruses ( Virology )

  Fungi ( Mycology )

  Parasites ( Parasitology )

  They cannot be seen with the naked eye
• Microbiology


  The study of microorganisms - microbes (minute living organisms – animal or plant), these may be Bacteria (Bacteriology), Viruses (Virology), Fungi (Mycology), Parasites (Parasitology). They cannot be seen with the naked eye.
• Clinical microbiology


  The main area of microbiology that is pursued in the hospital environment. All types of microorganisms are investigated in the hospital/health-related setting, with Bacteriology being the main emphasis.
• Bacteriology


  The study of bacteria to help in the identification, cause, treatment of infection these may cause. Bacteria may be pathogens (infection causing) or non-pathogens (normal flora found in some parts of the body).
• Effective bacteriology service


  1. Origin/site of the specimen

  2. The nature of investigation needed

  3. The normal flora (if any) of the area where specimen was taken

  4. Diagnosis and clinical history
• Microorganisms are responsible for cycling of elemental Carbon, Nitrogen, Phosphorus, Hydrogen, Sulphur & Oxygen
• More photosynthesis is carried out by microbes than by green plants
• Relationship between microbes and man

  • Microorganisms as disease agents
  • Microorganisms & agriculture
  • Microorganisms & Food
  • Energy & the environment
  • Organisms now and in the future
• Bacteria, Fungi & Viruses cause many diseases that affect man, animals & plants
• Nitrogen fixation by Rhizobium in nodules on roots of leguminous plants
• Cellulose digesting bacteria in the rumens of herbivorous animals
• Food production- cheeses, yoghurts, pickled products, alcoholic beverages, breads
• Food spoilage due to microbial growth & foodborne illness
• Natural gas (methane) is a product of methanogenic bacteria
• Microbes can be used to clean up the environment in a process called Bioremediation; organisms can degrade spilled oil, solvents, pesticides
• In large scale industrial processes, genetically modified microbes are used to synthesize products like antibiotics, insulin
• Microbiology is required to face threat of new and reemerging human infectious disease & develop industrial technologies that are more efficient & environmentally friendly
• Production of new drugs & vaccines to counter the spread of multiple antibiotic resistance
• Further development of molecular techniques to facilitate study of microbes in their natural environment (microbial ecology)
• Proteomics & genomics- sequencing of microbial genomes, study of protein structure & function
• Provide understanding of how structures develop, how cells communicate & function within the environment
• Hippocrates of Kos


  Father of Western medicine. First description of clubbing of the fingers, an important diagnostic sign in chronic suppurative lung disease, lung cancer and cyanotic heart disease. Began the categorization of illnesses as acute, chronic, endemic and epidemic.
• Antony van Leeuwenhoek


  A dealer in men's clothing and accessories. Spent his spare time constructing simple microscopes. Beginning 1673 he sent detailed letters to Royal Society of London describing his discoveries, including bacteria and protozoa.
• Joseph Lister


  English surgeon who developed a system of antiseptic surgery designed to prevent microorganisms from entering wounds. Published his findings in 1867.
• Robert Koch


  A German physician who did the first direct demonstration of the role of bacteria in causing disease from the study of anthrax using mice. Developed Koch's postulates to show the causal relationship between microorganism and a specific disease. Isolated the bacillus that causes tuberculosis in 1882.
• Koch's Postulates


  • The microorganism must be present in every case of the disease but absent from healthy individuals
  • The suspected microorganism must be isolated and grown in pure culture
  • The same disease must result when the isolated microorganism is inocculated into a healthy host
  • The same microorganism must be isolated from animals in which the illness has been induced.
• Elie Metchnikoff


  He discovered that some blood leukocytes could engulf disease-causing bacteria. These blood cells were called phagocytes and the process phagocytosis (Phagein – eating)Gk. He also contributed to the development of immunology.
• Friedrich Loeffler


  A German bacteriologist who discovered the organism causing Diphtheria (whooping cough), Corynebacterium diphtheriae and also the cause of foot and mouth disease, Aphthovirus. He also created Loffler's serum used for the detection of the bacteria causing Diphtheria.
• Kiyoshi Shiga


  A Japanese physician and bacteriologist. He discovered Shigella dysenteriae, the bacillus causing dysentery in 1897.
• Albert Calmette


  A French physician, bacteriologist and immunologist. He discovered the Bacillus Calmette-Guerin, an attenuated form of Mycobacterium used in the BCG vaccine against tuberculosis. Organized the production of vaccines against smallpox and rabies. Carried out research on cholera.
• Sir Alexander Flemming


  A Scottish biologist and pharmacologist. In 1928 he discovered the antibiotic substance penicillin from the mould Penicillin notatum. Penicillin turned out to be an infection-fighting agent of enormous potency, used against syphilis, gangrene and tuberculosis.
• Jonas Salk


  An American medical researcher and virologist best known for his discovery and development of the first safe and effective polio vaccine in 1955.
• Albert Sabin


  An American medical researcher who developed an oral polio vaccine. He also helped to develop a vaccine against Japanese encephalitis.
• John Snow


  An English physician who has been called the founder of epidemiology based on his work during the great cholera epidemic in England in 1854.
• Edward Jenner


  English physician and scientist. Called the father of Immunology. Pioneered the development of the smallpox vaccine. In 1796 he tried his hypothesis about smallpox by inoculating pus from a milk maid who had cow pox into a 8 y-o boy.
• Jules Bordet


  Belgian pioneering immunologist. He along with Gengou discovered the bacteria that causes whooping cough (Bodetella pertussis) in 1906. Medium used to grow bacteria called Bordet-Gengou medium. After WW1, he found how thrombin forms and how platelets participate in clotting.
• Other Contributors and the development of Microbiology

  • 1847-1850: Semmelweis introduces antibiotics
  • 1933: Ruska develops electron microscope
  • 1983-84: HIV isolated & identified by Gallo & Montagnier; Mullis develops PCR technique
  • 1995: Chicken pox vaccine approved for U.S. use; Haemophilus influenzae genome sequenced
  • 2005: "Super resistant" HIV strain isolated in NYC