Introduction to Medical Microbiology ,

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Introduction to Medical Microbiology ,

  1. 1. INTRODUCTION TOMEDICAL MICROBIOLOGY Dr.T.V.Rao MD Dr.T.V.Rao MD 1
  2. 2. What is Microbiology?Microbes, or microorganisms are minute livingthings that are usually unable to be viewed with thenaked eye.What are some examples of microbes?Bacteria, fungi, protozoa, algae, viruses areexamples!Some are pathogenicMany are beneficial Dr.T.V.Rao MD 2
  3. 3. Defining Microbiology Microbiology defined as the studyof organisms too small to be seen withthe naked eye. These organisms includeviruses, bacteria, algae, fungi, andprotozoa. Microbiologists are concernedwith characteristics and functions such asmorphology, cytology, physiology,ecology, taxonomy, genetics, andmolecular biology. Dr.T.V.Rao MD 3
  4. 4. What is Microbiology• Study of different Microorganisms• Can be Bacteria Viruses Parasites Fungus Dr.T.V.Rao MD 4
  5. 5. What are Microorganisms• Microbes are products of evolution, Consequence of Natural selection operating upon vast array of genetically diverse organisms Dr.T.V.Rao MD 5
  6. 6. History of Microbiology1673-1723, Antonivan Leeuwenhoek(Dutch) describedlivemicroorganismsthat he observed inteeth scrapings,rain water, andpeppercorninfusions. Dr.T.V.Rao MD 6
  7. 7. Anton van Leeuwenhoek 1674- 1st person to actually see living microorganisms 荷兰人吕文虎克 (Leeuwenhoek)1632-1723 “wee animalcules” Dr.T.V.Rao MD 7
  8. 8. History of MicrobiologyThe Germ Theory of Disease1835: 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. 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. 10. History of microbiology Anton van Leeuwenhoek (1632–1723): was the firstmicrobiologist and the first person to observe bacteriausing a single-lens microscope of his own design. Louis Pasteur (1822–1895): Pasteur developed aprocess (today known as pasteurization) to kill microbes.pasteurization is accomplished by heating liquids to 63to 65 C for 30 minutes or to 73 to 75 C for 15 seconds. Robert Koch (1843–1910): was a pioneer in medicalmicrobiology and worked in cholera, anthrax andtuberculosis. He was awarded a Nobel prize in 1905(Kochs postulates) he set out criteria to test. Alexander Fleming (1929): Discovered penicillin. Dr.T.V.Rao MD 10
  11. 11. 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 11
  12. 12. 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 12
  13. 13. Other Objectives• To teach the basic immunological principles• Immunological methods for the study immunological disorders Dr.T.V.Rao MD 13
  14. 14. Coverage of subject• General Microbiology• Bacteriology• Mycology• Virology• Immunology• Parasitology Dr.T.V.Rao MD 14
  15. 15. 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 15
  16. 16. Dr.T.V.Rao MD 16
  17. 17. 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 17
  18. 18. Classification of Microorganisms• Three domains – Bacteria – Archaea – Eukarya • Protists • Fungi • Plants • Animals Dr.T.V.Rao MD 18
  19. 19. 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 19
  20. 20. Edward Jenner Vaccinating a Child Dr.T.V.Rao MD 20
  21. 21. Louis Pasteur 1922 - 95• Contributed best in Microbiology• Sterilization• Hot Air oven• Autoclave• Anthrax vaccine• Rabies vaccine• Built the Pasteur Institute Dr.T.V.Rao MD 21
  22. 22. Louis Pasteur• Pasteur coined the word Vaccine• Vacca – Cow cow pox virus are given for the prevention of Small Pox• Louis Pasteur considered the father of Modern Microbiology Dr.T.V.Rao MD 22
  23. 23. Robert Koch 1843 - 1910• A German scientist• Formulated the Bacteriological techniques• Staining Methods• Discovered the Mycobacterium and Vibrio cholera Dr.T.V.Rao MD 23
  24. 24. Biological Principles illustrated by Microbiology Microbiology MolecularBiochemistry Genetics Biology Dr.T.V.Rao MD 24
  25. 25. Microorganisms Non-cellular organism Virus Prokaryotes Bacterium Eukaryotes FungiOthers Prions Viroid Dr.T.V.Rao MD 25
  26. 26. Organisms included in the study of Microbiology1. Bacteria Bacteriology2. Protozoans Protozoology3. Algae Phycology4. Parasites Parasitology5. Yeasts and Molds Fungi Mycology6. Viruses Virology Dr.T.V.Rao MD 26
  27. 27. Man has Evolved So also the Microbes Dr.T.V.Rao MD 27
  28. 28. How to Study Medical Microbiology? Fundamentals of Microbiology •Biological Properties Bacteriology •Morphology, identification, •Antigenic structure •Pathogenesis and Pathology •Clinical findings •Diagnostic Laboratory Tests Virology •Immunity •Treatment & Prevention •Epidemiology & Control Mycology Dr.T.V.Rao MD 28
  29. 29. Basic Classification of Microorganism • Eukaryotes ProkaryotesLarge in size Small in SizeMitochondria Present DNA not separated fromMembrane bound Nucleus cytoplasmEg Algae Mitochondria absent Protozoa Fungi Eg Bacteria Slime MouldsContains all enzymes for Contains all enzymes like production of metabolic Eukaryotes energy Dr.T.V.Rao MD 29
  30. 30. Summary of differences between prokaryote and eukaryote cells Prokaryotic cells Eukaryote cellsSmall cell (< 5µm) Larger cells (> 10 µm)Always unicellular Often multicellularNo nucleus or any membrane bound organelles Always have nucleus and membranes bound organelles.DNA circular, without proteins DNA is linear and associated with proteins to form chromatin.Ribosomes are small 70S Ribosomes are large 80SNo cytoskeleton Always have cytoskeletonMotility by rigid rotating flagellum made from Motility by flexible waving cilia or flagellaflagellin made from tubulins.Cell division is by binary fission Cell division is by meiosis and mitosis.Reproduction is always asexual Reproduction is sexual and asexual.
  31. 31. Prokaryotic Cell Structure Prokaryotic cells are about 10 times smallerthan eukaryotic cells. A typical Escherichia colicell is about 1 μm wide and 2 to 3 μm long.Structurally, prokaryotes are very simple cellswhen compared with eukaryotic cells, and yetthey are able to perform the necessaryprocesses of life. Reproduction of prokaryoticcells is by binary fission, the simple division ofone cell into two cells, after DNA replication andthe formation of a separating membrane and cellwall.
  32. 32. Bacteria • Prokaryotes • Peptidoglycan cell walls • Binary fission • For energy, use organic chemicals, inorganic chemicals, or photosynthesis Dr.T.V.Rao MD 32
  33. 33. Bacterial Cell Wall The structure of bacterial cell walls is quite different fromthe relatively simple structure of eukaryotic cell walls,although they serve the same functions, providing rigidity,strength, and protection. The main constituent of mostbacterial cell walls is a complex macromolecular polymerknown as peptidoglycan (murein), consisting of manypolysaccharide chains linked together by small peptide(protein) chains. Peptidoglycan is only found in bacteria. Thethickness of the cell wall and its exact composition vary withthe species of bacteria. The cell walls of “Gram-positivebacteria” have a thick layer of peptidoglycan combined withteichoic acid and lipoteichoic acid molecules. The cell walls of“Gram-negative bacteria” have a much thinner layer ofpeptidoglycan, but this layer is covered with a complex layerof lipid macromolecules, usually referred to as bacteriacapsule.
  34. 34. Figure 1-9: Gram Stain
  35. 35. 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.
  36. 36. Morphologic arrangements of bacteria.
  37. 37. Capsule stain. The capsule stain is an example of a negative staining technique. Thebacterial cells and the background stain, but the capsules do not. The capsules are seen as unstained “halos” around the bacterial cells.
  38. 38. . 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.
  39. 39. Binary fission. Note that DNA replication must occur before the actual splitting (fission) of the parent cell.
  40. 40. Pathogenic Prokaryotes Bacteria Mycoplasma Spirochetes Chlamydiae Rickettsia Actinomyces Dr.T.V.Rao MD 40
  41. 41. VirusesA viral particle consists of a nucleic acid molecule, either DNA or RNA,enclosed in a protein coat, or capsidViruses lack many of the attributes of cells, including the ability toreplicate. Only when it infects a cell does a virus acquire the keyattribute of a living system: reproductionViruses are known to infect all cells, including microbial cells. Host-virusinteractions tend to be highly specific Dr.T.V.Rao MD 41
  42. 42. Discovery of Virus• Iwanovski – a Russian chemist, 1892 – Tobacco Mosaic Disease• Beijerinck confirmed• Walter Reed, USA – Yellow fever virus – Ist human virus Tobacco mosaic disease, caused by the tobacco mosaic virus Dr.T.V.Rao MD 42
  43. 43. 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 43
  44. 44. 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 44
  45. 45. PrionA kind of infectious protein that can resist the digestion of proteinaseThe cellular form of the prion protein (PrPc) is encoded by the host’schromosomal DNAAn abnormal isoform of this protein (PrPres) is the only knowncomponent 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 45
  46. 46. ViroidSmall, single-stranded, covalently closed circular RNA moleculesexisting as highly base-pairedrod-like structures; they do not possess capsidsThey range in size from 246 to 375 nucleotides in length. Theextracellular form of the viroid is naked RNA—there is no capsid of anyThe RNA molecule contains no protein-encoding genes, and the viroidkindis therefore totally dependent on host functions for its replicationThe RNAs of viroids have been shown to containinverted repeated base sequences at their 3 and 5 ends, acharacteristic of transposable elements and retroviruses. Thus, it islikely that they have evolvedfrom transposable elements or retroviruses by the deletion of internalsequences Dr.T.V.Rao MD 46
  47. 47. Koch’s Postulates1 The bacterium should be constantly associated with lesions of Disease2 It should be possible to isolate the bacterium in pure culture from the lesions3 Inoculation of such pure culture into laboratory animal should reproduce the lesions of the disease4 It is possible to reisolate the bacterium in pure culture from the lesions produced in the experimental animal Additional criterion specific antibodies in the serum of patients suffering with disease Dr.T.V.Rao MD 47
  48. 48. Koch’s postulates Dr.T.V.Rao MD 48
  49. 49. Scientific era of Antibiotics1928: 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. Dr.T.V.Rao MD 49
  50. 50. Discovery of Antibiotics • Alexander Fleming (1881-1955)Sir Alexander Fleming Ernst Boris Chain Sir Howard Walter Florey Dr.T.V.Rao MD 50
  51. 51. Microbes are used to produce Antibiotics • Penicillin • Mold – Pencillium notatum • 1928 Alexander Fleming Dr.T.V.Rao MD 51
  52. 52. Modern Developments• Bacteriology is the study of bacteria.• Mycology is the study of fungi.• Parasitology is the study of protozoa and parasitic worms.• Recent advances in genomics, the study of an organism’s genes, have provided new tools for classifying microorganisms. Dr.T.V.Rao MD 52
  53. 53. Microbes and Human Disease• Normal micro biota prevent growth of pathogens.• Normal micro biota produce growth factors such as folic acid and vitamin K.• Resistance is the ability of the body to ward off disease.• Resistance factors include skin, stomach acid, and antimicrobial chemicals. Dr.T.V.Rao MD 53
  54. 54. How to Study Medical Microbiology?Fundamentals of Microbiology •Biological PropertiesBacteriology •Morphology, identification, •Antigenic structure •Pathogenesis and Pathology •Clinical findings •Diagnostic Laboratory TestsVirology •Immunity •Treatment & Prevention •Epidemiology & ControlMycology Dr.T.V.Rao MD 54
  55. 55. 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 55
  56. 56. • Staphylococcus aureus • Escherichia coli• Staphylococcus • Bacillus anthrasis epidermidis • Salmonella enteridis• Streptococcus • Streptococcus pyogenes pneumonia • Steptococcus lactis • Streptococcus faecalis• Vibrio cholera • Erlichia canis• Rhodospirillium rubrum • Campylobacter jujuni• Bacillus subtilis • Helicobacter pylori• Micrococcus luteus • Enterobacter aerogenes Dr.T.V.Rao MD 56
  57. 57. Microbes Benefit Humans1.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 57
  58. 58. Microbes are also capable of causing many diseasesPneumonia Whooping CoughBotulism Typhoid Fever MeaslesCholera Scarlet Fever MumpsSyphilis Gonorrhea Herpes 1Chlamydia Tuberculosis Herpes 2Meningitis Tetanus RMSVStrep Throat Lyme Disease AIDSBlack PlagueDiarrhea Dr.T.V.Rao MD Gangrene 58
  59. 59. 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 59
  60. 60. 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 60
  61. 61. 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 61
  62. 62. 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 62
  63. 63. 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)
  64. 64. Taxonomic classification of parasitic organisms• Parasites are classified into 2 sub- kingdoms: protozoa (unicellular) and metazoa (multicellular)• Protozoan (unicellular) parasites are classified according to morphology and means of locomotion. There are 45,000 protozoa species. Most species that cause human disease belong to the phylums sarcomastigophora and apicomplexa• Metazoa (multicellular) include the worms (helminths) and arthropoda (posses an external skeleton) e.g. ticks, lice Dr.T.V.Rao MD 64
  65. 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. 66. Zoonotic Diseases Dr.T.V.Rao MD 66
  67. 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. 68. Pathogenesis Immunity Dr.T.V.Rao MD 68
  69. 69. Immunity Protects the Living by Complex Mechanisms Dr.T.V.Rao MD 69
  70. 70. Why we should Medical Microbiology• We study the Microbes which infects and causes Diseases• We study their Diagnosis Prevention Treatment Dr.T.V.Rao MD 70
  71. 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. 72. Must learn• Natural History of the Disease• Etiology• Pathogenesis• Laboratory Diagnosis• Treatment and Control and Prevention Dr.T.V.Rao MD 72
  73. 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. 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. 75. Commonly Used Antibiotics• Penicillin• Cephalosporins,• Tetracyclines• Quinolones• Vancomycin• Chloramphenicol• Drugs for Tuberculosis eg Streptomycin Dr.T.V.Rao MD 75
  76. 76. Vaccines Produce Immunityand Prevents Several Infections Dr.T.V.Rao MD 76
  77. 77. Commonly used Vaccines• Small pox eradicated• BCG,• MMR• Polio oral Vaccine• Triple Antigen• Hepatitis B Vaccine Dr.T.V.Rao MD 77
  78. 78. What Skills You should DevelopAble to identify the Infective ConditionsTimely DiagnosisChoosing appropriate testsSelection of AntibioticsImplement measures to prevent diseases in patients and Society Dr.T.V.Rao MD 78
  79. 79. Protect Yourself from Infections• Certain infections can infect you• Eg HIV, Hepatitis B infections,Tubercul osis,Many respiratory infections Dr.T.V.Rao MD 79
  80. 80. Working In the Hospital• Hospitals are not safe• Follow Universal precaution protect yourself as our patients can be source of Infection if you dont handle the matters with scientific knowledge. Dr.T.V.Rao MD 80
  81. 81. Medical Microbiology advanced Beyond our Imagination Can we handle it ??? Dr.T.V.Rao MD 81
  82. 82. Major Selected Nobel Prizes in Physiology or Medicine1901* von Behring Diphtheria antitoxin1902 Ross Malaria transmission1905 Koch TB bacterium1908 Metchnikoff Phagocytes1945 Fleming, Chain, Florey Penicillin1952 Waksman Streptomycin1969 Delbrück, Hershey, Luria Viral replication1987 Tonegawa Antibody genetics1997 Prusiner Prions* The first Nobel Prize in Physiology or Medicine. Dr.T.V.Rao MD 82
  83. 83. 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 83
  84. 84. • The Programme created byDr.T.V.Rao MD for Medical students in the Developing world • Email • doctortvrao@gmail.com Dr.T.V.Rao MD 84

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