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A beginning to Medical microbiology

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A beginning to Medical microbiology

A beginning to Medical microbiology


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  • 1. A BEGINNING TO MEDICAL MICROBIOLOGY Dr.T.V.Rao MD Dr.T.V.Rao MD 1
  • 2. What is Microbiology? Microbes, or microorganisms are minute living things that are usually unable to be viewed with the naked eye. What are some examples of microbes? Bacteria, fungi, protozoa, algae, viruses are examples! Some are pathogenic Many are beneficial as Commensal bacteria Dr.T.V.Rao MD 2
  • 3. Microbiology defined as the study of organisms too small to be seen with the naked eye. These organisms include viruses, bacteria, algae, fungi, and protozoa. Microbiologists are concerned with characteristics and functions such as morphology, cytology, physiology, ecolog y, taxonomy, genetics, and molecular biology. Defining Microbiology Dr.T.V.Rao MD 3
  • 4. What is Microbiology •Study of different Microorganisms •Can be Bacteria Viruses Parasites Fungus Dr.T.V.Rao MD 4
  • 5. Microbial World is Fascinating •Viruses •Bacteria (Eubacteria) and Archaeabacteria •Fungi (Yeasts and Molds) •Protozoa •Microscopic Algae Dr.T.V.Rao MD 5
  • 6. What are Microorganisms •Microbes are products of evolution, Consequ ence of Natural selection operating upon vast array of genetically diverse organisms Dr.T.V.Rao MD 6
  • 7. History of Microbiology 1673-1723, Antoni van Leeuwenhoek (Dutch) described live microorganisms that he observed in teeth scrapings, rain water, and peppercorn infusions. Dr.T.V.Rao MD 7
  • 8. Scientific History of Microbiology The Germ Theory of Disease 1835: Agostino Bassi showed a silkworm disease was caused by a fungus. 1865: Pasteur believed that another silkworm disease was caused by a protozoan. 1840s: Ignaz Semmelweis advocated handwashing to prevent transmission of puerperal fever from one OB patient to another. Dr.T.V.Rao MD 8
  • 9. The Germ Theory of Disease • 1860s: Joseph Lister used a chemical disinfectant to prevent surgical wound infections after looking at Pasteur’s work showing microbes are in the air, can spoil food, and cause animal diseases. Dr.T.V.Rao MD 9
  • 10. Pioneers of Microbiology •Robert Hooke, UK (1665) •Proposed the Cell Theory •Observed cork with crude microscope •All living things are composed of cells •Spontaneous generation •Some forms of life could arise spontaneously from non-living matter •Francesco Redi, IT (1668) •Redi’s experiments first to dispprove S.G.Dr.T.V.Rao MD 10
  • 11. Pioneers of Microbiology • Antoni van Leeuwenhoek, DE (1673) • First observed live microorganisms (animalcules) • Schleiden and Schwann, DE • Formulated Cell Theory: cells are the fundamental units of life and carry out all the basic functions of living things • Pasteur, FR and Tyndall, UK (1861) • Finally disproved S.G. Dr.T.V.Rao MD 11
  • 12. 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 •Proposed aseptic techniques (prevent contamination by unwanted microbes) •Director of Pasteur Institute, Paris (1894) Dr.T.V.Rao MD 12
  • 13. Pioneers of Microbiology •Joseph Lister, UK (1867) •Used phenol (carbolic acid) to disinfect wounds •First aseptic technique in surgery •Robert Koch, DE (1876) •Postulates – Germ theory (1876) •Identified microbes that caused anthrax (1876), tuberculosis (1882) and cholera (1883) •Developed microbiological media & streak plates for pure culture (1881) Dr.T.V.Rao MD 13
  • 14. History of microbiology  Anton van Leeuwenhoek (1632–1723): was the first microbiologist and the first person to observe bacteria using a single-lens microscope of his own design.  Louis Pasteur (1822–1895): Pasteur developed a process (today known as pasteurization) to kill microbes. pasteurization is accomplished by heating liquids to 63 to 65 C for 30 minutes or to 73 to 75 C for 15 seconds.  Robert Koch (1843–1910): was a pioneer in medical microbiology and worked in cholera, anthrax and tuberculosis. He was awarded a Nobel prize in 1905 (Koch's postulates) he set out criteria to test.  Alexander Fleming (1929): Discovered penicillin. Dr.T.V.Rao MD 14
  • 15. Joseph Lister •1860s: Joseph Lister used a chemical disinfectant to prevent surgical wound infections after looking at Pasteur’s work showing microbes are in the air, can spoil food, and cause animal diseases. Dr.T.V.Rao MD 15
  • 16. Learning Objectives •To teach the basic immunological principles •Immunological methods for the study immunological disorders Dr.T.V.Rao MD 16
  • 17. We all should be Familiar with •General Microbiology •Bacteriology •Mycology •Virology •Immunology •Parasitology Dr.T.V.Rao MD 17
  • 18. Microbes in Our Lives •Microorganisms are organisms that are too small to be seen with the unaided eye. •“Germ” refers to a rapidly growing cell. Dr.T.V.Rao MD 18
  • 19. Microbes make the Universe •There are > 5 x 1030 types Microbes in the world •Humans have intimate relation with Microbes > 90% of the cells in our Body are Microbes Dr.T.V.Rao MD 19
  • 20. Classification of Microorganisms •Three domains •Bacteria •Archaea •Eukarya •Protists •Fungi •Plants •Animals Dr.T.V.Rao MD 20
  • 21. Naming and Classifying Microorganisms •Carolus Linnaeus (1735) established the system of scientific nomenclature. •Each organism has two names: the genus and specific epithet. •Are italicized or underlined. The genus is capitalized and the specific epithet is lower case.Dr.T.V.Rao MD 21
  • 22. Edward Jenner Vaccinating a Child Dr.T.V.Rao MD 22
  • 23. Louis Pasteur 1922 - 1995 •Contributed best in Microbiology •Sterilization •Hot Air oven •Autoclave •Anthrax vaccine •Rabies vaccine •Built the Pasteur Institute Dr.T.V.Rao MD 23
  • 24. Louis Pasteur •Vacca – Cow cow pox virus are given for the prevention of Small Pox •Louis Pasteur considered the father of Modern Microbiology •Pasteur coined the word Vaccine Dr.T.V.Rao MD 24
  • 25. Robert Koch 1843 - 1910 •A German scientist •Formulated the Bacteriological techniques •Staining Methods •Discovered the Mycobacterium and Vibrio cholera Dr.T.V.Rao MD 25
  • 26. Koch's Postulates 1. Microorganisms are isolated from dead animals 2. Microorganisms are grown in pure culture 2b. Microorganisms are identified 3. Microorganisms are injected into healthy animals 4. Disease is reproduced in second animal 5. Microorganisms are grown in pure culture 5b. Identification of identical microorganism. Dr.T.V.Rao MD 26
  • 27. Koch’s Postulates Dr.T.V.Rao MD 27
  • 28. Figure 14.3, steps 1–2 Dr.T.V.Rao MD 28
  • 29. Figure 14.3, steps 3–4 Dr.T.V.Rao MD 29
  • 30. Figure 14.3, step 5 Dr.T.V.Rao MD 30
  • 31. Exceptions to Koch’s Postulates • Microorganisms that are unable to be cultured on artificial media • (example: Treponema pallidum) • More organism work in synergy to cause a disease. • Symptoms and diseases can be causes by any one of several microbes. Dr.T.V.Rao MD 31
  • 32. Biological Principles illustrated by Microbiology Dr.T.V.Rao MD 32 Microbiology Biochemistry Molecular Biology Genetics
  • 33. Microorganisms Non-cellular organism Prokaryotes Eukaryotes Others Prions Viroid Fungi Bacterium Virus Dr.T.V.Rao MD 33
  • 34. Organisms included in the study of Microbiology 1. Bacteria 2. Protozoans 3. Algae 4. Parasites 5. Yeasts and Molds Fungi 6. Viruses Bacteriology Protozoology Phycology Parasitology Mycology Virology Dr.T.V.Rao MD 34
  • 35. How to Study Medical Microbiology? Dr.T.V.Rao MD 35 Fundamentals of Microbiology Bacteriology Virology Mycology •Biological Properties •Morphology, identification, •Antigenic structure •Pathogenesis and Pathology •Clinical findings •Diagnostic Laboratory Tests •Immunity •Treatment & Prevention •Epidemiology & Control
  • 36. Basic Classification of Microorganism •Eukaryotes Large in size Mitochondria Present Membrane bound Nucleus Eg Algae Protozoa Fungi Slime Moulds Contains all enzymes for production of metabolic energy Prokaryotes Small in Size DNA not separated from cytoplasm Mitochondria absent Eg Bacteria Contains all enzymes like Eukaryotes Dr.T.V.Rao MD 36
  • 37. Prokaryotic Cell Structure Prokaryotic cells are about 10 times smaller than eukaryotic cells. A typical Escherichia coli cell is about 1 μm wide and 2 to 3 μm long. Structurally, prokaryotes are very simple cells when compared with eukaryotic cells, and yet they are able to perform the necessary processes of life. Reproduction of prokaryotic cells is by binary fission, the simple division of one cell into two cells, after DNA replication andDr.T.V.Rao MD 37
  • 38. Bacteria •Prokaryotes •Peptidoglycan cell walls •Binary fission •For energy, use organic chemicals, inorganic chemicals, or photosynthesis Dr.T.V.Rao MD 38
  • 39. Bacterial Cell Wall The structure of bacterial cell walls is quite different from the relatively simple structure of eukaryotic cell walls, although they serve the same functions, providing rigidity, strength, and protection. The main constituent of most bacterial cell walls is a complex macromolecular polymer known as peptidoglycan (murein), consisting of many polysaccharide chains linked together by small peptide (protein) chains. Peptidoglycan is only found in bacteria. The thickness of the cell wall and its exact composition vary with the species of bacteria. The cell walls of “Gram-positive bacteria” have a thick layer of peptidoglycan combined with teichoic acid and lipoteichoic acid molecules. The cell walls of “Gram-negative bacteria” have a much thinner layer of peptidoglycan, but this layer is covered with a complex layer of lipid macromolecules, usually referred to as bacteria capsule. Dr.T.V.Rao MD 39
  • 40. Figure 1-9: Gram StainDr.T.V.Rao MD 40
  • 41. Figure 3-1. Various forms of bacteria, including single cocci, diplococci, tetrads, octads, streptococci, staphylococci, single bacilli, diplobacilli, streptobacilli, branching bacilli, loosely coiled spirochetes, and tightly coiled spirochetes. Dr.T.V.Rao MD 41
  • 42. Capsule stain. The capsule stain is an example of a negative staining technique. The bacterial cells and the background stain, but the capsules do not. The capsules are seen as unstained “halos” around the bacterial cells. Dr.T.V.Rao MD 42
  • 43. . Flagellar arrangement. The four basic types of flagellar arrangement on bacteria: peritrichous, flagella all over the surface; lophotrichous, a tuft of flagella at one end; amphitrichous, one or more flagella at each end; monotrichous, one flagellum. Dr.T.V.Rao MD 43
  • 44. Binary fission. Note that DNA replication must occur before the actual splitting (fission) of the parent cell. Dr.T.V.Rao MD 44
  • 45. Pathogenic Prokaryotes Mycoplasma Bacteria Spirochetes Rickettsia Chlamydiae Actinomyces Dr.T.V.Rao MD 45
  • 46. Viruses Viruses lack many of the attributes of cells, including the ability to replicate. Only when it infects a cell does a virus acquire the key attribute of a living system: reproduction A viral particle consists of a nucleic acid molecule, either DNA or RNA, enclosed in a protein coat, or capsid Viruses are known to infect all cells, including microbial cells. Host-virus interactions tend to be highly specific Dr.T.V.Rao MD 46
  • 47. Discovery of Virus •Iwanovski •a Russian chemist, 1892 •Tobacco Mosaic Disease •Beijerinck confirmed •Walter Reed, USA •Yellow fever virus •Ist human virus Dr.T.V.Rao MD 47 Tobacco mosaic disease, caused by the tobacco mosaic virus
  • 48. Viruses •A virus is not a cell! •Viruses are replicated only when they are in a living host cell •Consist of DNA or RNA core •Core is surrounded by a protein coat •Coat may be enclosed in a lipid envelope Dr.T.V.Rao MD 48
  • 49. What are Viruses • Viruses Dependent on Host cells for necessary functions and Multiplication •Intracellular parasites •Contain either DNA or RNA never both. Dr.T.V.Rao MD 49
  • 50. Prion A kind of infectious protein that can resist the digestion of proteinase The cellular form of the prion protein (PrPc) is encoded by the host’s chromosomal DNA An abnormal isoform of this protein (PrPres) is the only known component of the prion and is associated with transmissibility. Kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann- Sträussler-Scheinker disease, fatal familial insomnia , and Bovine spongiform encephalopathy (BSE) Dr.T.V.Rao MD 50
  • 51. Viroid Small, single-stranded, covalently closed circular RNA molecules existing as highly base-paired rod-like structures; they do not possess capsids They range in size from 246 to 375 nucleotides in length. The extracellular form of the viroid is naked RNA—there is no capsid of any kind The RNA molecule contains no protein-encoding genes, and the viroid is therefore totally dependent on host functions for its replication The RNAs of viroids have been shown to contain inverted repeated base sequences at their 3' and 5' ends, a characteristic of transposable elements and retroviruses. Thus, it is likely that they have evolved from transposable elements or retroviruses by the deletion of internal sequences Dr.T.V.Rao MD 51
  • 52. 1928: Alexander Fleming discovered the first antibiotic. He observed that Penicillium fungus made an antibiotic, penicillin, that killed S. aureus. 1940s: Penicillin was tested clinically and mass produced. Scientific era of Antibiotics Dr.T.V.Rao MD 52
  • 53. Discovery of Antibiotics• Alexander Fleming (1881-1955) Sir Alexander Fleming Ernst Boris Chain Sir Howard Walter Florey Dr.T.V.Rao MD 53
  • 54. Microbes are used to produce Antibiotics Penicillin Penicillin •Mold • Pencillium notatum •1928 Alexander Fleming Dr.T.V.Rao MD 54
  • 55. How to Study Medical Microbiology? Dr.T.V.Rao MD 55 Fundamentals of Microbiology Bacteriology Virology Mycology •Biological Properties •Morphology, identification, •Antigenic structure •Pathogenesis and Pathology •Clinical findings •Diagnostic Laboratory Tests •Immunity •Treatment & Prevention •Epidemiology & Control
  • 56. Bacteria - what comes to mind? •Diseases •Infections •Epidemics •Food Spoilage •Only 1% of all known bacteria cause human diseases •About 4% of all known bacteria cause plant diseases •95% of known bacteria are non-pathogens Dr.T.V.Rao MD 56
  • 57. •Staphylococcus aureus •Staphylococcus epidermidis •Streptococcus pneumonia •Vibrio cholera •Rhodospirillium rubrum •Bacillus subtilis •Micrococcus luteus •Escherichia coli •Bacillus anthrasis •Salmonella enteridis •Streptococcus pyogenes •Steptococcus lactis •Streptococcus faecalis •Erlichia canis •Campylobacter jujuni •Helicobacter pylori •Enterobacter aerogenes Dr.T.V.Rao MD 57
  • 58. Microbes Benefit Humans 1.Bacteria are primary decomposers - recycle nutrients back into the environment (sewage treatment plants) 2. Microbes produce various food products •cheese, pickles, sauerkraut, green olives •yogurt, soy sauce, vinegar, bread •Beer, Wine, Alcohol Dr.T.V.Rao MD 58
  • 59. Microbes are also capable of causing many diseases Pneumonia Whooping Cough Botulism Typhoid Fever Measles Cholera Scarlet Fever Mumps Syphilis Gonorrhea Herpes 1 Chlamydia Tuberculosis Herpes 2 Meningitis Tetanus RMSV Strep Throat Lyme Disease AIDS Black Plague Diarrhea Gangrene Dr.T.V.Rao MD 59
  • 60. Progress of Hepatitis Viruses • 1947, concepts of hepatitis A and serum- transmitted hepatitis • 1970, Dane particle was observed (hepatitis B virus) • 1973, hepatitis A virus • 1978, non-A, non-B hepatitis viruses (NANBV) • 1989, hepatitis C virus (HCV), hepatitis E virus (HEV) • 1990-1994, non A-E hepatitis viruses • 1995, hepatitis G virus (HGV) • 1997, TT virus (TTV) Dr.T.V.Rao MD 60
  • 61. Human Immunodeficiency Virus & AIDS •1981, the first cases report about AIDS •1983, HIV was isolated •1990s, HAART (cocktail therapy) was employed •So far, no effective vaccine available Dr.T.V.Rao MD 61
  • 62. HIV – AIDS•Luc Montaigner and Robert Gallo announce their discovery of the immunodeficiency virus (HIV) believed to cause AIDS. (American Society for Microbiology Archives)Dr.T.V.Rao MD 62
  • 63. Parasitology •Parasitology is the study of parasites .and their interactions with their hosts. The science of parasitology has a long history and has its roots in zoology, with its emphasis on the identification and classification of parasites and of life cycles, Dr.T.V.Rao MD 63
  • 64. Taxonomic classification of parasitic organisms •The classification of parasites is controversial - there is no universally accepted system •Parasites form part of the animal kingdom which comprises some 800,000 identified species categorised into 33 phyla (but it is estimated that there may be ~10m species in total) •The parasitic organisms that are of importance for human health are eukaryotes - they have a well defined chromosome in a nuclear membrane (as opposed to prokaryotes which have no nuclear membrane, e.g. bacteria) Dr.T.V.Rao MD 64
  • 65. What Are Fungi •Considerable variation in size. •Internal Molecular system •Well defined cell wall composed of polysaccharides •Gaining importance in Immunosupressed patients and increased use of Antibiotics Dr.T.V.Rao MD 65
  • 66. Zoonotic Diseases Dr.T.V.Rao MD 66
  • 67. How Humans Respond to Infections Study of Immunology •In spite of Infection we survive with our ability to protect with a system inherent in our Body •Called the Immune response comprises the Medical Immunology Dr.T.V.Rao MD 67
  • 68. Modern Developments in Microbiology •Immunology is the study of immunity. Vaccines and interferons are being investigated to prevent and cure viral diseases. •The use of immunology to identify some bacteria according to serotypes (variants within a species) was proposed by Rebecca Lancefield in 1933. Figure 1.4 (3 of 3) Dr.T.V.Rao MD 68
  • 69. Pathogenesis Immunity Dr.T.V.Rao MD 69
  • 70. Why we should learn Medical Microbiology •We study the Microbes which infects and causes Diseases •We study their Diagnosis Prevention Treatment Dr.T.V.Rao MD 70
  • 71. Modern Developments in Microbiology • Immunology is the study of immunity. Vaccines and interferons are being investigated to prevent and cure viral diseases. • The use of immunology to identify some bacteria according to serotypes (variants within a species) was proposed by Rebecca Lancefield in 1933. Dr.T.V.Rao MD 71
  • 72. Must learn •Natural History of the Disease •Etiology •Pathogenesis •Laboratory Diagnosis •Treatment and Control and Prevention Dr.T.V.Rao MD 72
  • 73. We must be familiar with Knowledge On …. •Names of the Microbes •Names of the diseases •Mode of transmission •Pathogenic Microbes •Commensal Organisms •Identify wether Bacteria, Virus, Parasite or Fungi •Treating and Preventing Dr.T.V.Rao MD 73
  • 74. The Birth of Modern Chemotherapy •Treatment with chemicals is chemotherapy. •Chemotherapeutic agents used to treat infectious disease can be synthetic drugs or antibiotics. •Antibiotics are chemicals produced by bacteria and fungi that inhibit or kill other microbes. •Quinine from tree bark was long used to treat malaria. •1910: Paul Ehrlich developed a synthetic arsenic drug, salvarsan, to treat syphilis. •1930s: Sulfonamides were synthesized. Dr.T.V.Rao MD 74
  • 75. Commonly Used Antibiotics •Penicillin •Cephalosporins, •Tetracycline's •Quinolones •Vancomycin •Chloramphenicol •Drugs for Tuberculosis eg Streptomycin Dr.T.V.Rao MD 75
  • 76. Vaccines Produce Immunity and Prevents Several Infections Dr.T.V.Rao MD 76
  • 77. Commonly used Vaccines •Small pox eradicated •BCG, •MMR •Polio oral Vaccine •Triple Antigen •Hepatitis B Vaccine Dr.T.V.Rao MD 77
  • 78. Course objectives •To provide the student with the basic knowledge of micro-organisms in general •To study the main characteristics of Microbes of medical importance •To teach aseptic techniques •To provide an understanding of antimicrobial agents Dr.T.V.Rao MD 78
  • 79. What Skills You should Develop Able to identify the Infective Conditions Timely Diagnosis Choosing appropriate tests Selection of Antibiotics Implement measures to prevent diseases in patients and Society Dr.T.V.Rao MD 79
  • 80. Protect Yourself from Infections •Certain infections can infect you •Eg HIV, Hepatitis B infections,Tubercu losis,Many respiratory infections Dr.T.V.Rao MD 80
  • 81. Working In the Hospital •Hospitals are not safe •Follow Universal precaution protect yourself as our patients can be source of Infection if you don't handle the matters with scientific knowledge. Dr.T.V.Rao MD 81
  • 82. Medical Microbiology advanced Beyond our Imagination Can we handle it ??? Dr.T.V.Rao MD 82
  • 83. Major Selected Nobel Prizes in Physiology or Medicine * The first Nobel Prize in Physiology or Medicine. Dr.T.V.Rao MD 83 1901* von Behring Diphtheria antitoxin 1902 Ross Malaria transmission 1905 Koch TB bacterium 1908 Metchnikoff Phagocytes 1945 Fleming, Chain, Florey Penicillin 1952 Waksman Streptomycin 1969 Delbrück, Hershey, Luria Viral replication 1987 Tonegawa Antibody genetics 1997 Prusiner Prions
  • 84. Students requirement for the course •Timetable •Literature – books, etc •Practical manual •Laboratory coat •Attendance and active participation •Seek advice timely Dr.T.V.Rao MD 84
  • 85. •The Programme Created by Dr.T.V.Rao MD for medical and paramedical Students in the Developing World •Email •doctortvrao@gmail.com Dr.T.V.Rao MD 85