Introduction to Microbiology & Bacterial Growth Lecture 1 Dr. Santhosh Puthiyakunnon, Ph.D., Professor, Dept. of Microbiology, School of Tropical Medicine & Public Health Southern Medical University, Guangzhou. Ph: +86-13268121594 E Mail: santhoshpk73@hotmail.com Introduction to Microbiology & Bacterial Growth Microbiology ⚫ ⚫ From the ancient history, human believed that unseen forces or poisonous vapours from decomposing matters could cause the disease – Spontaneous degeneration Germ theory vs Spontaneous degeneration ⚫ Varo and Colmella – “Animalia minuta” : Diseases caused by invisible organisms ⚫ Fracastorius of Verona – “Contagium vivum” : Living germs cause infectious diseases ⚫ Von Plenciz – Each disease caused by separate agent Microbiology ⚫ ⚫ ⚫ ⚫ ⚫ Microbiology is the science of living organisms that are visible under microscope Microbes are important cause of diseases Microbes are important Resources They are also indispensable for normal life of other organisms In Agriculture, Industries and Features of Microbes M = Microscopic in Food microbiology I = Independent units C = Complex (less) R = Rapid growth rate O = Omnipresent Classification of Microorganisms ⚫ Based on morphological & functional properties, microbes are grouped as: Bacteria are small, unicellular, microscopic organisms with primitive nucleus Fungi are unicellular or multicellular microscopic organisms with well- developed nucleus. They possess plant-like characters but are devoid of chlorophyll and are not differentiated into roots, stem, leaves, etc. Algae are unicellular or multicellular microscopic organisms possessing plant-like characters. They possess chlorophyll but are not differentiated into roots, stem, leaves, flowers, etc. Most of them possess well-developed nucleus, except blue green algae Protozoa are unicellular, nonphotosynthetic microscopic organisms possessing animal-like characters, i.e. they do not possess rigid cell wall. They have a well-developed nucleus Viruses are very small, ultramicroscopic (seen under electron microscope), noncellular microorganisms capable of multiplying only inside the living cell. They are different from other living creatures Scientific Contributions to the development of Microbiology ⚫ Antony van leeuwenhoek (1632 – 1723) ⚫ Louis Pasteur (1822 – 1895) ⚫ Joseph Lister (1827 – 1912) ⚫ Robert Koch (1843 – 1910) ⚫ Paul Ehrlich (1854 – 1915) ⚫ Alexander Fleming (1881 – 1955) Antony van Leeuwenhoek ⚫ 1676 – first observation of bacteria “animalcules” Antony van Leeuwenhoek Draper from Holland, grinding lenses as hobby ⚫ Described three major morphological forms of bacteria and communicated to Royal Society of London (1683) ⚫ Constructed over 250 small powerful microscope which could magnify 300 times ⚫ World of “Little animalcules” remained dormant for two centuries till their role in infectious diseases were recognized ⚫ Edward Jenner ⚫ 1796 – First vaccine (smallpox) Historical Events ⚫ 1857 – Germ Theory of Disease Louis Pasteur Historical Events ⚫ 1885 - Vaccine against Rabies Louis Pasteur Louis Pasteur Father of Microbiology ⚫ Fermentation and microorganisms ⚫ Trained chemist from France ⚫ Contributions : ⚫ 1. 2. 3. 4. 5. ⚫ Disproved the Theory of Spontaneous degeneration Introduction of Sterilization techniques Established differing growth needs of different bacteria Studies on Anthrax, Chicken cholera and Hydrophobia Live attenuated Vaccines : Coined the term ‘vaccine’ - Chicken cholera, Anthrax, Rabies Pasteur Institute, Paris Joseph Lister ⚫ 1867 Antiseptic Surgery Joseph Lister Father of Antiseptic surgery ⚫ Professor of Surgery, Glasgow ⚫ Use of Carbolic acid as antiseptics ⚫ Pronounced drop in mortality and morbidity due to surgical sepsis ⚫ Robert Koch ⚫ 1884 Koch’s Postulates of Disease Transmission Robert Koch German general practitioner ⚫ Father of Medical Microbiology ⚫ Contributions: 1. Introduced methods of isolation of pure strains of bacteria 2. Solid bacterial culture media 3. Introduced staining techniques 4. Discovered Anthrax bacillus, TB and Cholera vibrios 5. Formulated postulates for proving the etiology of infectious diseases : Koch’s postulates ⚫ Paul Ehrlich German scientist – Father of Chemotherapy ⚫ Contributions : ⚫ 1. Staining of cells and tissues for study of their functions 2. Reported acid-fast nature of tubercle bacilli 3. Proposed ‘side chain theory’ of antibody production 4. Discovered salvarsan – an arsenical against sprirochete causing syphilis : ‘magic bullet’. This lead to the origin of a new aspect of medicine : Chemotherapy 5. Introduced methods of standardising toxin and antitoxin Sir Alexander Fleming (1881 –1955) “One sometimes finds what one is not looking for” Penicillin He observed inhibition of staphylococci on an agar plate contaminated by a Penicillium mold Historical Events ⚫ 1929 Discovery of Penicillin (first antibiotic) Alexander Fleming Historical Events ⚫ 1938 – First Electron Microscope ⚫ The electron microscope is capable of magnifying biological specimens up to one million times. These computer enhanced images of 1. smallpox, 2. herpes simplex, and 3. mumps are magnified, respectively, 150,000, 150,000 and 90,0000 times. Historical Events 1953 Structure of DNA Revealed Watson & Crick Historical Events 1954 Polio Vaccine Jonas Salk Microbiology ⚫ Bacteria Virus Fungi Protozoa Algae Helminthes ⚫ Kingdom : Protista ⚫ ⚫ ⚫ ⚫ ⚫ : : : : : : Bacteriology Virology Mycology Protozoology Phycology Helminthology 1. Prokaryotes - Bacteria & Blue green algae 2. Eukaryotes - Fungi, Slime, Moulds & Protozoa SIZE OF MICROORGANISMS ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ Unit of measurement used in Bacteriology : Micron (μm) 1 μm = 1 thousands of a millimetre Unit of measurement used in Virology : Nanometer 1 nm = 1 thousandth of a micron Limit of resolution of unaided eye = 200 μm Bacteria of medical importance = 0.2 -1.5 μm in diameter and 3-5 μm in length Microscopy : - Magnification of object - Resolution - contrast TYPES OF MICROSCOPES ⚫ Optical or Light Microscope ⚫ Phase Contrast Microscope ⚫ Dark field Microscope ⚫ Interference Microscope ⚫ Fluorescent Microscope ⚫ Electron Microscope GROWTH & NUTRITION OF BACTERIA Bacterial Multiplication: Binary fission ⚫ Generation time ⚫ Bacterial count : ⚫ - Total count - Viable count ⚫ Bacterial Growth Curve : - Lag Phase Log Phase Stationary Phase Phase of Decline GROWTH ON GROWTH ON SOLID CULTURE MEDIA LIQUID CULTURE (BROTH) BACTERIAL COUNTING CHAMBERS COULTER COUNTER TURBIDITY COMPARISON ABSORPTIOMETER OR NEPHALO METER Bacterial Growth Curve Bacterial Nutrition ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ Moisture and Desiccation Oxygen Carbon dioxide Temperature pH Light Osmotic Effect Mechanical & Sonic stress Reference Textbooks ⚫ Textbooks for Students Reference: ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ ⚫ Textbook of Microbiology (2016) – Ananthnarayana & Jayaram Panicker Principles of Microbiology – Bailey & Scott Medical Microbiology – Jawetz Microbiology- Pelzar Karp G (2010) Cell Biology- Wiley & Sons Dimmock et al. (2008) Introduction to modern Virology Black J (2012) Microbiology- Wiley Madigam et.al (2008)- Biology of Microorganisms Wheelis M (2008) Principles of Modern Microbiology Review Questions Q1. List 4- 5 important contributions of the following scientists: ⚫ Antony van Leeuwenhoek (1632 – 1723) ⚫ Louis Pasteur (1822 – 1895) ⚫ Joseph Lister (1827 – 1912) ⚫ Robert Koch (1843 – 1910) ⚫ Paul Ehrlich (1854 – 1915) ⚫ Alexander Fleming (1881 – 1955) Review Questions Q 1. Describe the different phases of Bacterial growth curve listing the changes happening in bacterial cell morphology. Q 2. Differentiate between batch culture and continuous culture. Q 3. Define the terms: total and viable bacterial counts. Q 4. Discuss the different factors which effect the bacterial growth and multiplication. Project Work ⚫ Make a project work on all different types of Microscopes including its parts, principle of working, uses and precautions while usage. ⚫ Make a Poster presentation on “Evolution of Microscope” as described previously in the audio. THANK YOU ! 59
