1.MICROBIOLOGY FORMEDICAL GRADUATESWHAT YOU SHOULD KNOWDr.T.V.Rao MDDR.T.V.RAO MD 11/16/2012 1

2. 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 MD11/16/2012 2 3. WHAT IS MEDICAL MICROBIOLOGY?The study of microorganisms(including bacteria, viruses, fungiand parasites) which are of medical importance and arecapable of causing diseases in human beingsDR.T.V.RAO MD 11/16/2012 3 4. THE EARLY YEARS OF MICROBIOLOGYCONTRIBUTED BY DISCOVERY OF MICROSCOPEDR.T.V.RAO MD11/16/2012 4 5. THE FIRST OBSERVATIONS 1673-1723, Antonivan Leeuwenhoekdescribed livemicroorganisms thathe observed inteeth scrapings, rainwater, andpeppercorninfusions.DR.T.V.RAO MD 11/16/2012 5 Figure 1.2b 6. THE EARLY YEARS OF MICROBIOLOGY How Can Microbes Be Classified? Carolus Linnaeus (Swedish) developed taxonomic system for naming plants and animals and grouping similar organisms together Leeuwenhoeks microorganisms grouped into six categories as follows: Fungi Protozoa Algae Bacteria Archaea Small animals DR.T.V.RAO MD11/16/2012 6 7. WHAT IS MEDICAL MICROBIOLOGY? THE PURPOSE OF LEARNINGWhat organisms cause infection?How they cause infection.How to treat them.How to prevent infection.DR.T.V.RAO MD11/16/2012 7 8. WHY IS IT IMPORTANT? Infection is one of the most importantcauses of mortality and morbidity in thepopulation. Approximately 30% of hospital patientsare on antibiotics at any one time 1 in 10 patients acquires an infectionwhilst in hospital.DR.T.V.RAO MD 11/16/2012 8 9. THE HISTORICAL CONTRIBUTION IN THESUBJECT OF MICROBIOLOGY BY Darwin Linnaeus Salk Jenner Watson & Crick Jacob and Monod Hooke McClintockWoese Leeuwenhoek Venter? Lister Pasteur KochDR.T.V.RAO MD11/16/2012 9 10. DEFINITIONS 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 organismsgenes, have provided new tools for classifyingmicroorganisms. Proteomics is looking at the gene productsDR.T.V.RAO MD11/16/2012 10 11. LEARN THE CLASSIFICATION OF ORGANISMS All living organisms are classified into: Kingdom Phylum (family) Genus Species Organisms that can cause disease are many and varied and include: Viruses Bacteria Fungi ParasitesDR.T.V.RAO MD11/16/2012 11 12. RELEVANCE OF CLASSIFICATION Different: Diseases Modes oftransmission Treatment-e.g.routinely useantibiotics dont curevira lfungalinfectionsDR.T.V.RAO MD11/16/2012 12 13. THE GOLDEN AGE OF MICROBIOLOGY LOUIS PASTEUR CHANGES THE FUTURE OFMICROBIOLOGYDR.T.V.RAO MD11/16/2012 13 14. FERMENTATION AND PASTEURIZATION Pasteur demonstrated thatthese spoilage bacteria couldbe killed by heat that was nothot enough to evaporate thealcohol in wine. Pasteurization is theapplication of a high heat for ashort time.DR.T.V.RAO MD11/16/201214Figure 1.4 (1 of 3) 15. THE GOLDEN AGE OF MICROBIOLOGYDR.T.V.RAO MD 11/16/2012 15 16. THE GOLDEN AGE OF MICROBIOLOGY Kochs Postulates Suspected causative agent must be found inevery case of the disease and be absent fromhealthy hosts Agent must be isolated and grown outside thehost When agent is introduced into a healthy,susceptible host, the host must get the disease Same agent must be reisolated from now-diseased experimental hostDR.T.V.RAO MD 11/16/2012 16 17. NORMAL MICROBIOTA Normal Microbiota prevent growth ofpathogens. Normal Microbiota produce growth factorssuch as folic acid and vitamin K. Resistance is the ability of the body toward off disease. Resistance factors include skin,stomach acid, and antimicrobialchemicals. Biofilms are extremely important inmicrobial ecology DR.T.V.RAO MD 11/16/2012 17 18. NORMAL MICRO BIOTA ON THE HUMAN BODYDR.T.V.RAO MD11/16/2012Table 1814.1 19. NORMAL MICROBIOTA Animals, including humans, are usually germfreein utero. Microorganisms begin colonization in and on thesurface of the body soon after birth. Microorganisms that establish permanent coloniesinside or on the body without producing diseasemake up the normal microbiota. Transient microbiota are microbes that arepresent for various periods and thendisappear.DR.T.V.RAO MD 11/16/2012 19 20. WE HAVE MORE MICROBES OCCUPYING OUR BODY THAN OUR OWN CELLSDR.T.V.RAO MD11/16/2012 20 21. CLASSIFYING BACTERIAWhy bother?Different bacteria: cause different diseases are susceptible/resistant todifferent antibiotics some bacteria are commonnormal flora whilst otherclosely related species arepathogensDR.T.V.RAO MD11/16/2012 21 22. CLASSIFYING BACTERIAHow? 1st into broad groups basedon microscopic appearance Then divided into speciesbased on a range ofdifferent properties-oftenbiochemical reactions e.g.some may be able tometabolise a sugar thatothers cannot.DR.T.V.RAO MD 11/16/2012 22 23. GRAM STAINMethod of differentiating bacteria.Can be either Gram +ve or Gram ve depending on how they appear with the stain.Can then be further grouped based on shape (rod=long thin or coccus=round).Thus we end up with 4 combinations:G+ rod, G+ coccus, G- rod, G- coccusDR.T.V.RAO MD 11/16/2012 23 24. BACTERIAL CELL WALL MAKES THEBASIC DIFFERENCEDR.T.V.RAO MD 11/16/2012 24 25. GRAM STAING+veG-ve STAIN the slide withcrystal violet for 1-2 min. Flood slide with Gramsiodine for 1-2 min. Decolourise by washingthe slide briefly withacetone (2-3 seconds). Stain with safranincounterstain for 2 min. View under microscope DR.T.V.RAO MD 11/16/2012 25 26. GRAM STAINGives an initial idea of the possible identity of the organism.Can be done without growingthe organism (i.e. rapidresult)Thus can be done on pus, jointfluid, sputum, CSF1st result available on bloodculturesDR.T.V.RAO MD11/16/2012 26 27. GRAM STAINRelevance of Gram reaction. Gram +ve and gram veorganisms ae susceptibleto different groups ofantibiotics. Cause different diseases Differ in their ability tosurvive in the environment-cleaning, infection control,outbreak management.DR.T.V.RAO MD11/16/2012 27 28. GRAM POSITIVE COCCI Clusters: usuallycharacteristic ofStaphylococcus spp., such as S. aureus Chain or pairs: usually characteristicof Streptococcus spp., such as S. pneumoniaeDR.T.V.RAO MD11/16/201228 29. GRAM POSITIVE BACILLI Thick : usuallycharacteristic ofClostridium spp., suchas C. perfringens, C.difficle, C. tetani Thin: e.g. Listeria spp.DR.T.V.RAO MD 11/16/2012 29 30. GRAM NEGATIVE BACILLI Thin rods: usually characteristic of enterobacteriaceae (coliforms), such as E. Coli Coccobacilli: usually characteristic of Haemophilus spp., such as H. influenzaeDR.T.V.RAO MD11/16/2012 30 31. GRAM NEGATIVE BACILLI Curved: usuallycharacteristic of Vibriospp.or Campylobacter spp.,such as V. cholerae C. jejuni Thin needle shape: usuallycharacteristic ofFusobacterium spp.DR.T.V.RAO MD 11/16/2012 31 32. GRAM NEGATIVE COCCI Diplococci: usually characteristic ofNeisseria spp., such as N.meningitides or N. gonorrhea.Though In addition, Moraxella spp.and Acinetobacter spp.are oftendiplococcal in morphology. Coccobacilli: usually characteristicof Acinetobacter spp., which can beeither Gram-positive or Gram-negative, and is often called Gram-variable.DR.T.V.RAO MD11/16/201232 33. WHAT CAN YOU SEE ON THE SLIDE?1.Gram +ve cocci2.Gram +ve bacilli3.Gram ve cocci4.Gram ve bacilli53%47% 0% 0%Staphylococcus aureus 100xillillii cc ccci ci co co ba ba eeee+vv +vv m m m mrarararaGGGG DR.T.V.RAO MD 11/16/201233 34. WHAT CAN YOU SEE ON THE SLIDE?1.Gram +ve cocci2.Gram +ve bacilli Streptococcus pneumoniae3.Gram ve cocci4.Gram ve bacilli 68% 16% 11% 5% i lli lli icccc cicicocobabae e e e +v v+v vmmmm ra ra ra ra G G G G DR.T.V.RAO MD 11/16/2012 34 35. WHAT CAN YOU SEE ON THE SLIDE?1. Gram +ve cocci2. Gram +ve bacilli3. Gram ve cocci4. Gram ve bacilli 36% 36% 14% 14% Pseudomonas aeruginosa i lli lli icccc cicicocobabae e e e +v v+v vmmmm ra ra ra ra G G G G DR.T.V.RAO MD 11/16/2012 35 36. VIRUSESSmall (50-300nm)Unable to replicateindependentlyInvade host cells and usetheir cellular machinery toreplicateInfluenza, Chickenpox(varicella), Herpes,Rhinovirus, HIV/AIDSOften difficult to treatDR.T.V.RAO MD 11/16/2012 36 37. FUNGI Complex, large organisms Eukaryotes (as are humans!) Divided into yeasts & moulds Cause a range of diseasese.g.: Thrush Athletes foot Invasive & allergic aspergillosis Many diseases areopportunistic.DR.T.V.RAO MD 11/16/2012 37 38. PROTOZOA Eukaryotes Absorb or ingestorganic chemicals May be motile viapseudopods, cilia,or flagellaDR.T.V.RAO MD11/16/201238Figure 1.1c 39. MULTICELLULAR ANIMALPARASITES Eukaryote Multicellular animals Parasitic flatworms and round worms are called Helminths. Microscopic stages in life cycles.DR.T.V.RAO MD11/16/201239Figure 12.28a 40. THE ETIOLOGY OF INFECTIOUS DISEASES Kochs postulates are criteria for establishing thatspecific microbes cause specific diseases. Kochs postulates have the following requirements:(a) the same pathogen must be present in every case ofthe disease;(b) the pathogen must be isolated in pure culture;(c) the pathogen isolated from pure culture must cause thesame disease in a healthy, susceptible laboratoryanimal;(d) the pathogen must be reisolated from the inoculatedlaboratory animal.DR.T.V.RAO MD11/16/2012 40 41. KOCHS POSTULATESDR.T.V.RAO MD 11/16/2012 41 Figure 14.7 42. EXCEPTIONS TO KOCHS POSTULATES Kochs postulates are modified to establish etiologies ofdiseases caused by viruses and some bacteria, which cannotbe grown on artificial media. Some diseases, such as tetanus, have unequivocal signsand symptoms. Some diseases, such as pneumonia and nephritis, may becaused by a variety of microbes. Some pathogens, such as S. pyrogenes, cause severaldifferent diseases. Certain pathogens, such as HIV, cause disease in humansonly.DR.T.V.RAO MD11/16/2012 42 43. Diseases and Infections Disease-causing microorganisms are called pathogens. Pathogenic microorganisms have special properties that allow them to invade the human body or produce toxins. When a microorganism overcomes the bodys defenses, a state of disease results.DR.T.V.RAO MD11/16/2012 43 44. PATHOLOGY, INFECTION, AND DISEASE Pathology is the scientific study of disease. Pathology is concerned with the etiology (cause), pathogenesis (development), effects of disease structural and functional changes broughtabout by disease. Infection is the invasion and growth of pathogens in the body. A host is an organism that shelters and supports the growth ofpathogens. Disease is an abnormal state in which part or all of the body is notproperly adjusted or is incapable of performing normal functions. Infection disease presence of particular microorganism in part ofthe body where is not usually found. DR.T.V.RAO MD11/16/201244 45. IMMUNITY PROTECTS FROM EVENTS WITH INFECTIONSDR.T.V.RAO MD11/16/2012 45 46. CLASSIFYING INFECTIOUS DISEASES Every disease alters body structures and functions A patient may exhibit symptoms (subjective changes in body functions) Pain or body discomfort signs (measurable changes), which a physician uses to make a diagnosis (identification of the disease) Fever, swelling, paralysis A specific group of symptoms or signs that alwaysaccompanies a specific disease is called asyndrome.DR.T.V.RAO MD 11/16/2012 46 47. MICROORGANISMSDR.T.V.RAO MD11/16/2012 47Figure 1.1 48. CLASSIFYING INFECTIOUS DISEASES Communicable diseases are transmitted directlyor indirectly from one host to another. Chicken pox, genital herpes, A contagious disease is one that is easily spread from one person to another. Noncommunicable diseases are caused bymicroorganisms that normally grow outside thehuman body and are not transmitted from onehost to another Tetanus, Clostridium tetani DR.T.V.RAO MD11/16/2012 48 49. THE MODERN AGE OF MICROBIOLOGYDR.T.V.RAO MD 11/16/2012 49 50. THE MODERN AGE OF MICROBIOLOGY Microbial Genetics Avery, MacLeod, and McCarty determined genes are contained in molecules of DNA Beadle and Tatum established that a genes activity is related to protein function Translation of genetic information into protein explained Rates and mechanisms of genetic mutation investigated Control of genetic expression by cells described DR.T.V.RAO MD11/16/2012 50 51. THE MODERN AGE OF MICROBIOLOGY Molecular Biology Explanation of cell function at the molecular level Genome sequencing Pauling proposed that gene sequences could Provide understanding of evolutionary relationships and processes Establish taxonomic categories that reflect these relationships Identify existence of microbes that have never been cultured Woese determined that cells belong to bacteria, archaea, or eukaryotes Cat-scratch fever caused by unculturable organism DR.T.V.RAO MD 11/16/2012 51 52. THE MODERN AGE OFMICROBIOLOGY Recombinant DNA Technology Genes in microbes, plants, and animals manipulated for practical applications Production of human blood- clotting factor by E. coli to aid hemophiliacs Gene Therapy Inserting a missing gene or repairing a defective one in humans by inserting desired gene into host cellsDR.T.V.RAO MD11/16/2012 52 53. DISCOVERY OF ANTIMICROBIAL AGENTS_________ Alexander Fleming (1881 1955), a Scottish biologist and pharmacologist, observed bacterial staphylococci colonies disappearing on plates contaminated with mold. Fleming extracted the compound from the mold responsible for destruction of the bacterial colonies. The product of the mold was named penicillin, after the Penicillium mold from which it was derived. Nobel Prize in Physiology of Medicine in 1945. Images: Penicillium mold, PHIL #8396; Staphylococcus aureus on DR.T.V.RAO MD 11/16/201253antibiotic test plate, PHIL #2641; Poster attached to a mailboxFrom the Virtual Microbiology Classroom on ScienceProfOnline.comoffering advice to World War II servicemen, 1944, NIH 54. THE MODERN AGE OF MICROBIOLOGY How Do We Defend Against Disease? Serology The study of blood serum Von Behring and Kitasato existence in the blood ofchemicals and cells that fight infection Immunology The study of the bodys defense against specific pathogens Chemotherapy Fleming discovered penicillin Domagk discovered sulfa drugs DR.T.V.RAO MD11/16/201254 55. THE BIRTH OF MODERNCHEMOTHERAPY Treatment with chemicals is chemotherapy. Chemotherapeutic agents used to treat infectious diseasecan be synthetic drugs or antibiotics. Antibiotics are chemicals produced by bacteria and fungithat 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 11/16/2012 55 56. THE BIRTH OF MODERN CHEMOTHERAPY 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. DR.T.V.RAO MD11/16/2012 56 57. MODERN DEVELOPMENTS IN MICROBIOLOGY Immunology is the study ofimmunity. Vaccines andinterferons are being investigatedto prevent and cure viraldiseases. The use of immunology to identifysome bacteria according toserotypes (variants within aspecies) was proposed byRebecca Lancefield in 1933.DR.T.V.RAO MD11/16/201257Figure 1.4 (3 of 3) 58. MODERN BIOTECHNOLOGY AND GENETIC ENGINEERING Biotechnology, the use ofmicrobes to produce foodsand chemicals, is centuriesold. Genetic engineering is anew technique forbiotechnology. Throughgenetic engineering,bacteria and fungi canproduce a variety ofproteins including vaccinesand enzymes.DR.T.V.RAO MD 11/16/2012 58 59. SELECTED NOBEL PRIZES IN PHYSIOLOGYOR MEDICINE1901* von BehringDiphtheria antitoxin1902Ross Malaria transmission1905Koch TB bacterium1908MetchnikoffPhagocytes1945Fleming, Chain, Florey Penicillin1952WaksmanStreptomycin1969Delbrck, Hershey, Luria Viral replication1987Tonegawa Antibody genetics.1997Prusiner PrionsDR.T.V.RAO MD 11/16/2012 59 60. SELECTED NOVEL PRIZES IN PHYSIOLOGY OR MEDICINE1901* von Behring Diphtheria antitoxin1902RossMalaria transmission1905KochTB bacterium1908Metchnikoff Phagocytes1945Fleming, Chain, FloreyPenicillin1952Waksman Streptomycin1969Delbrck, Hershey, LuriaViral replication1987TonegawaAntibody genetics1997PrusinerPrions2003Agre, Mackirron water and ion channels2005 Marshall, WarrenHelicobacter and ulcers2008 Hausen Papilloma and viruses* The first Nobel Prize in Physiology or Medicine.DR.T.V.RAO MD11/16/2012 60 61. UNIVERSAL PRECAUTIONS SET UP BY CDC Use gloves, gowns, masks and goggles Minimize risk of needle sticks Disinfections procedure Preventative treatment after exposure Reduce risk Treat all patients the same HBV greater risk than HIVDR.T.V.RAO MD 11/16/2012 61 62. DEAR STUDENTS NEVER FORGET TO WASH HANDS AFTER HANDLING PATIENTS OR INFECTEDMATERIALDR.T.V.RAO MD 11/16/2012 62 63. VISIT ME FOR MORE ARTICLES OF INTEREST ONMICROBIOLOGY, INFECTIOUS DISEASESDR.T.V.RAO MD 11/16/2012 63 64. Programme Created by Dr.T.V.Rao MDfor Undergraduate Medical andParamedical Students for orientation inLearning Medical Microbiology email doctortvrao@gmail.comDR.T.V.RAO MD11/16/2012 64