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Introduction toMedical Microbiology     Dr.T.V.Rao MD
Aim of the Programme• The world is going for more and more towards the  Digital learning ( e-learning). The Subject of  Me...
Aims for Learning Medical            Microbiology• What is medical  microbiology?• Why is it relevant?• Some important  co...
What is Microbiology? Microbes, or microorganisms are minute livingthings that are usually unable to be viewed with       ...
What is Microbiology• Microbiology – study of  microorganisms (simple forms of life  visible only with a microscope)• Micr...
Why is it Important?• Infection is one of the most important  causes of mortality and morbidity in the  population.• Appro...
The Early Years of Microbiology contributed by           discovery of Microscope                    Dr.T.V.Rao MD          7
History of Microbiology started with1673-1723, Antonivan Leeuwenhoek(Dutch) describedlive microorganismsthat he observed i...
Pioneers of Microbiology• Antoni van Leeuwenhoek, DE (1673)  – First observed live microorganisms    (animalcules)• Schlei...
Pioneers of Microbiology• Louis Pasteur (1822-1895), Chemist  – Fermentation (1857)  – Pasteurization: heat liquid enough ...
Pioneers of Microbiology• Joseph Lister, UK (1867)  – Used phenol (carbolic acid) to disinfect wounds  – First aseptic tec...
The Golden Age of Microbiology            1857-1914Beginning with Pasteur’s work, discoveriesincluded the relationship bet...
Microbiology• The study of organisms too small to    be seen without magnification– bacteria– viruses– fungi– protozoa– He...
Classification of Organisms• All living organisms are classified into:     •   Kingdom     •   Phyllum (family)     •   Ge...
Branches of study within            Microbiology• Immunology• Public health microbiology &  epidemiology• Food, dairy and ...
Microbes are involved in• nutrient production & energy flow• decomposition• production of foods, drugs &  vaccines• biorem...
Impact of pathogens• Nearly 2,000 different microbes  cause diseases• 10 B infections/year worldwide• 13 M deaths from inf...
Dr.T.V.Rao MD   18
Characteristics of microbes           Dr.T.V.Rao MD      19
Dr.T.V.Rao MD   20
Antonie van Leeuwenhoek                        • First to observe                          living microbes                ...
Science of Microbiology begins            Dr.T.V.Rao MD    22
Scientific Method• Form a hypothesis - a tentative  explanation that can be supported or  refuted by observation &  experi...
Hypothesis becomes Principles• If hypothesis is supported by a growing body of  evidence & survives rigorous scrutiny, it ...
Spontaneous generation   Early belief that some forms of life could arise from vital forces present in   nonliving or deco...
Louis Pasteur Laid foundations       in Microbiology                         • Showed microbes                            ...
Germ theory of disease   Replaces Fate and SinsMany diseases are caused by the growthof microbes in the body and not by si...
Robert Koch               1843 - 1910  A German scientist• Formulated the  Bacteriological  techniques• Staining Methods• ...
Robert Koch                     • Established a sequence of                       experimental steps to                   ...
Robert Koch establishes many             Principals and postulations• Koch perfected his methods of diagnostics and expand...
Robert Koch and Postulates• Koch’s work on diseases and  diagnostics culminated with the  creation of what are now known a...
How do we know that a given pathogen      causes a specific disease?                    • Kochs postulates  – the pathogen...
Kochs Postulates1.   Microorganisms are isolated from dead animals2.   Microorganisms are grown in pure culture2b. Microor...
Dr.T.V.Rao MD               34                Figure 14.3, steps 1–2
Dr.T.V.Rao MD               35                Figure 14.3, steps 3–4
Dr.T.V.Rao MD   36                     5
Exceptions to Koch’s Postulates• Microorganisms that are unable to  be cultured on artificial media   –(example: Treponema...
Joseph Lister• Joseph Lister, was a  British surgeon and a  pioneer of antiseptic  surgery. By applying  Louis Pasteurs ad...
Joseph Lister• He instructed surgeons under his responsibility  to wear clean gloves and wash their hands before  and afte...
Joseph Lister• Lister successfully  introduced carbolic  acid (now known as  phenol) to sterilise  surgical instruments  a...
Taxonomy - system for organizing,      classifying & naming living things•   Domain - Archaea, Bacteria & Eukarya•   Kingd...
Domains• Eubacteria -true bacteria,  peptidoglycan• Archaea –odd bacteria that live in  extreme environments, high salt,  ...
Dr.T.V.Rao MD   43
Naming Microorganisms• Binomial (scientific) nomenclature• Gives each microbe 2 names  – Genus - noun, always capitalized ...
Evolution- living things change    gradually over millions of years• Changes favoring survival are retained & less  benefi...
Bacteria• 500-800nm• Capable of independent  replication• Cause of most infections  seen in hospital• Pneumonia, bacterial...
Viruses• Smallest known  infectious agents• Subcellular  microorganism  – Have only nucleic acid    surrounded by a protei...
VirusesSmall (50-300nm)Unable to replicateindependentlyInvade host cells and usetheir cellular machinery toreplicateInflue...
Viruses (cont.)• Illnesses caused by viruses  – Colds                                    –   AIDS  – Influenza            ...
Fungi• Complex, large organisms• Eukaryotes (as are humans!)• Divided into yeasts &  moulds• Cause a range of diseases  e....
Fungi• Eukaryotic organisms  with rigid cell wall         • Superficial infections• Yeasts                               –...
Multicellular Parasites• Organisms that live on or in another organism and  use it for nourishment• Parasitic worms       ...
Protozoans• Single-celled eukaryotic organisms, larger than  bacteria• Found in soil and water• Illnesses   – Malaria     ...
Normal Flora• Human beings are not microbiologically  sterile.• We are ALL covered with bacteria, fungi  and some parasite...
How Microorganisms Cause            Disease (cont.)• Localized symptoms      • Generalized symptoms  –   Swelling         ...
How Microorganisms Cause          Disease• Cause disease in variety of ways  – Use nutrients needed by cells and tissues  ...
How Infections Are Diagnosed• Steps to diagnosis and treatment  1. Examine the patient    • Presumptive diagnosis    • May...
How Infections Are Diagnosed                   (cont.) 3. Examine specimen directly   • Wet mount   • Smear 4. Culture spe...
How Infections Are Diagnosed (cont.)                      5. Determine                         sensitivity to             ...
• Programme created by Dr.T.V.Rao MD  for Medical and Paramedical Students in           the Developing World              ...
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Introduction to medical microbiology

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Introduction to medical microbiology

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  1. 1. Introduction toMedical Microbiology Dr.T.V.Rao MD
  2. 2. Aim of the Programme• The world is going for more and more towards the Digital learning ( e-learning). The Subject of Medical Microbiology is wide and deep and given time period to learn many details becomes difficult. However students can orient with Digital modules for rapid learning and makes their online searches easier for rapid references. Dr.T.V.Rao MD Professor of Microbiology Dr.T.V.Rao MD 2
  3. 3. Aims for Learning Medical Microbiology• What is medical microbiology?• Why is it relevant?• Some important concepts.• Basic classification of organisms.• Classifying bacteria. Dr.T.V.Rao MD 3
  4. 4. What is Microbiology? Microbes, or microorganisms are minute livingthings 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 “Germ” refers to a rapidly growing cell. Dr.T.V.Rao MD 4
  5. 5. What is Microbiology• Microbiology – study of microorganisms (simple forms of life visible only with a microscope)• Microorganisms may be – Normal flora – Pathogenic
  6. 6. 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. Dr.T.V.Rao MD 6
  7. 7. The Early Years of Microbiology contributed by discovery of Microscope Dr.T.V.Rao MD 7
  8. 8. History of Microbiology started with1673-1723, Antonivan Leeuwenhoek(Dutch) describedlive microorganismsthat he observed inteeth scrapings, rainwater, andpeppercorninfusions. Dr.T.V.Rao MD 8
  9. 9. 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 9
  10. 10. 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 10
  11. 11. 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 11
  12. 12. The Golden Age of Microbiology 1857-1914Beginning with Pasteur’s work, discoveriesincluded the relationship between microbesand disease, immunity, and antimicrobialdrugs Dr.T.V.Rao MD 12
  13. 13. Microbiology• The study of organisms too small to be seen without magnification– bacteria– viruses– fungi– protozoa– Helminths (Parasites)– algae Dr.T.V.Rao MD 13
  14. 14. Classification of Organisms• All living organisms are classified into: • Kingdom • Phyllum (family) • Genus • Species• Organisms that can cause disease are many and varied and include: • Viruses • Bacteria • Fungi • Parasites Dr.T.V.Rao MD 14
  15. 15. Branches of study within Microbiology• Immunology• Public health microbiology & epidemiology• Food, dairy and aquatic microbiology• Biotechnology• Genetic engineering & recombinant DNA technology Dr.T.V.Rao MD 15
  16. 16. Microbes are involved in• nutrient production & energy flow• decomposition• production of foods, drugs & vaccines• bioremediation• causing disease Dr.T.V.Rao MD 16
  17. 17. Impact of pathogens• Nearly 2,000 different microbes cause diseases• 10 B infections/year worldwide• 13 M deaths from infections/year worldwide Dr.T.V.Rao MD 17
  18. 18. Dr.T.V.Rao MD 18
  19. 19. Characteristics of microbes Dr.T.V.Rao MD 19
  20. 20. Dr.T.V.Rao MD 20
  21. 21. Antonie van Leeuwenhoek • First to observe living microbes • his single-lens magnified up to 300X (1632-1723) Dr.T.V.Rao MD 21
  22. 22. Science of Microbiology begins Dr.T.V.Rao MD 22
  23. 23. Scientific Method• Form a hypothesis - a tentative explanation that can be supported or refuted by observation & experimentation• A lengthy process of experimentation, analysis & testing either supports or refutes the hypothesis.• Results must be published & repeated by other investigators. Dr.T.V.Rao MD 23
  24. 24. Hypothesis becomes Principles• If hypothesis is supported by a growing body of evidence & survives rigorous scrutiny, it moves to the next level of confidence - it becomes a theory• Evidence of a theory is so compelling that the next level of confidence is reached - it becomes a Law or principle Dr.T.V.Rao MD 24
  25. 25. Spontaneous generation Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter. (flies from manure, etc)
  26. 26. Louis Pasteur Laid foundations in Microbiology • Showed microbes caused fermentation & spoilage • Disproved spontaneous generation of m.o. • Developed aseptic techniques. • Developed a rabies (1822-1895) vaccine. Dr.T.V.Rao MD 26
  27. 27. Germ theory of disease Replaces Fate and SinsMany diseases are caused by the growthof microbes in the body and not by sins, bad character, or poverty, etc.
  28. 28. Robert Koch 1843 - 1910 A German scientist• Formulated the Bacteriological techniques• Staining Methods• Discovered the Mycobacterium and Vibrio cholera Dr.T.V.Rao MD 28
  29. 29. Robert Koch • Established a sequence of experimental steps to show that a specific m.o. causes a particular disease. • Developed pure culture methods. • Identified cause of anthrax, TB, & cholera.(1843-1910) Dr.T.V.Rao MD 29
  30. 30. 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.• 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.: Dr.T.V.Rao MD 30
  31. 31. 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.: Dr.T.V.Rao MD 31
  32. 32. How do we know that a given pathogen causes a specific disease? • Kochs 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 Dr.T.V.Rao MD 32
  33. 33. Kochs Postulates1. Microorganisms are isolated from dead animals2. Microorganisms are grown in pure culture2b. Microorganisms are identified3. Microorganisms are injected into healthy animals4. Disease is reproduced in second animal5. Microorganisms are grown in pure culture5b. Identification of identical microorganism. Dr.T.V.Rao MD 33
  34. 34. Dr.T.V.Rao MD 34 Figure 14.3, steps 1–2
  35. 35. Dr.T.V.Rao MD 35 Figure 14.3, steps 3–4
  36. 36. Dr.T.V.Rao MD 36 5
  37. 37. Exceptions to Koch’s Postulates• Microorganisms that are unable to be cultured on artificial media –(example: Treponema pallidum)• 2 or 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 37
  38. 38. Joseph Lister• Joseph Lister, was a British surgeon and a pioneer of antiseptic surgery. By applying Louis Pasteurs advances in microbiology, he promoted the idea of sterile surgery while working at the Glasgow Royal Infirmary.• . Dr.T.V.Rao MD 38
  39. 39. Joseph Lister• He instructed surgeons under his responsibility to wear clean gloves and 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. One of his additional suggestions was to stop using porous natural materials in manufacturing the handles of medical instruments. Dr.T.V.Rao MD 39
  40. 40. Joseph Lister• Lister successfully introduced carbolic acid (now known as phenol) to sterilise surgical instruments and to clean wounds, which led to a reduction in post- operative infections and made surgery safer for patients. Dr.T.V.Rao MD 40
  41. 41. Taxonomy - system for organizing, classifying & naming living things• Domain - Archaea, Bacteria & Eukarya• Kingdom - 5• Phylum or Division• Class• Order• Family• Genus• species Dr.T.V.Rao MD 41
  42. 42. Domains• Eubacteria -true bacteria, peptidoglycan• Archaea –odd bacteria that live in extreme environments, high salt, heat, etc• Eukarya- have a nucleus, & organelles Dr.T.V.Rao MD 42
  43. 43. Dr.T.V.Rao MD 43
  44. 44. Naming Microorganisms• Binomial (scientific) nomenclature• Gives each microbe 2 names – Genus - noun, always capitalized – species - adjective, lowercase• Both italicized or underlined – Staphylococcus aureus (S. aureus) – Bacillus subtilis (B. subtilis) – Escherichia coli (E. coli) Dr.T.V.Rao MD 44
  45. 45. Evolution- living things change gradually over millions of years• Changes favoring survival are retained & less beneficial changes are lost.• All new species originate from preexisting species.• Closely related organism have similar features because they evolved from common ancestral forms.• Evolution usually progresses toward greater complexity. Dr.T.V.Rao MD 45
  46. 46. Bacteria• 500-800nm• Capable of independent replication• Cause of most infections seen in hospital• Pneumonia, bacterial meningitis, cellulitis, UTI…• Many different species• Treated with antibiotics Dr.T.V.Rao MD 46
  47. 47. Viruses• Smallest known infectious agents• Subcellular microorganism – Have only nucleic acid surrounded by a protein coat Hepatitis virus – Must live and grow in living cells of other organisms Dr.T.V.Rao MD 47
  48. 48. VirusesSmall (50-300nm)Unable to replicateindependentlyInvade host cells and usetheir cellular machinery toreplicateInfluenza, Chickenpox(varicella), Herpes, Rhinovirus, HIV/AIDSOften difficult to treat Dr.T.V.Rao MD 48
  49. 49. Viruses (cont.)• Illnesses caused by viruses – Colds – AIDS – Influenza – Mumps – Croup – Rubella – Hepatitis – Measles – Warts – Herpes• Vaccines are available for many viruses Dr.T.V.Rao MD 49
  50. 50. Fungi• Complex, large organisms• Eukaryotes (as are humans!)• Divided into yeasts & moulds• Cause a range of diseases e.g.: – Thrush – Athletes foot – Invasive & allergic Aspergillosis• Many diseases are opportunistic. Dr.T.V.Rao MD 50
  51. 51. Fungi• Eukaryotic organisms with rigid cell wall • Superficial infections• Yeasts – Athlete’s foot – Single-celled – Ringworm – Reproduce by budding – Thrush• Molds – Large, fuzzy, • Can cause systemic multicelled organisms infections – Produce spores Dr.T.V.Rao MD 51
  52. 52. Multicellular Parasites• Organisms that live on or in another organism and use it for nourishment• Parasitic worms • Parasitic insects – Usually due to poor – Bite or burrow under the sanitation skin – Roundworms – Mosquitoes – Flatworms – Ticks – Tapeworms – Lice – mites Dr.T.V.Rao MD 52
  53. 53. Protozoans• Single-celled eukaryotic organisms, larger than bacteria• Found in soil and water• Illnesses – Malaria Protozoan – Amebic dysentery Trichomonas vaginalis – Trichomoniasis vaginitis• Leading cause of death in developing countries Dr.T.V.Rao MD 53
  54. 54. Normal Flora• Human beings are not microbiologically sterile.• We are ALL covered with bacteria, fungi and some parasites.• Skin, nose, mouth, gastrointestinal tract …• ~109 bacteria per gram of faeces• Each person carries more non-human cells on their body than their own Dr.T.V.Rao MD 54
  55. 55. How Microorganisms Cause Disease (cont.)• Localized symptoms • Generalized symptoms – Swelling – Fever – Pain – Tiredness – Warmth – Aches – Redness – Weakness • Normal flora – Provides a barrier – Can cause an infection Dr.T.V.Rao MD 55
  56. 56. How Microorganisms Cause Disease• Cause disease in variety of ways – Use nutrients needed by cells and tissues – Damage cells directly – Produce toxins• May remain localized or become systemic• Transmission – Direct contact – Indirect contact Dr.T.V.Rao MD 56
  57. 57. How Infections Are Diagnosed• Steps to diagnosis and treatment 1. Examine the patient • Presumptive diagnosis • May or may not need additional tests 2. Obtain specimen(s) • Label properly • Include presumptive diagnosis Dr.T.V.Rao MD 57
  58. 58. How Infections Are Diagnosed (cont.) 3. Examine specimen directly • Wet mount • Smear 4. Culture specimen Culture medium – contains nutrients Examine culture visually and microscopically Dr.T.V.Rao MD 58
  59. 59. How Infections Are Diagnosed (cont.) 5. Determine sensitivity to antibiotics 6. Treat the patient as ordered • Antimicrobial – to kill pathogen or suppress its growth Dr.T.V.Rao MD 59
  60. 60. • 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 60
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