Altamash classification & staphylococci

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Altamash classification & staphylococci

  1. 1. SYSTEMIC BACTERIOLOGY
  2. 2. CLASSIFICATION OF BACTERIA
  3. 3. <ul><li>TAXONOMY </li></ul><ul><li>Includes </li></ul><ul><li>Classification </li></ul><ul><li>Identification </li></ul><ul><li>Nomenclature </li></ul>
  4. 4. <ul><li>CLASSIFICATION </li></ul><ul><li> Is the arrangement of organisms into taxonomic groups on the basis of similarities or relationships (i.e. common properties). </li></ul><ul><li>IDENTIFICATION: </li></ul><ul><li> Is the practical use of a classification scheme to : Isolate & identify the causative agent of a disease. </li></ul><ul><li>NOMENCLATURE </li></ul><ul><li> Is naming of an organism by international rules according to its characteristics. Genera – Species – Sub species . </li></ul>
  5. 5. CLASSIFICATION OF MEDICALLY IMPORTANT BACTERIA BACTERIA RIGID THICK-WALLED CELLS FLEXIBLE, THIN-WALLED CELLS WALL-LESS CELLS
  6. 6. CLASSIFICATION OF MEDICALLY IMPORTANT BACTERIA RIGID THICK-WALLED CELLS FREE LIVING (EXTRACELLULAR ) NON FREE LIVING (OBLIGATE INTRACELLULAR PARASITES)
  7. 7. FREE LIVING BACTERIA GRAM POSITIVE BACTERIA GRAM NEGATIVE BACTERIA ACID-FAST BACTERIA COCCI <ul><ul><li>RODS </li></ul></ul>SPOREFORMING NONSPOREFORMING COCCI RODS
  8. 8. TETANUS CLOSTRIDIA (b)ANAEROBIC ANTHRAX BACILLUS (a) AEROBIC SPORE FORMING RODS (AEROBIC/ ANAEROBIC) RODS (SPORE FORMING RODS/ NON SPORE FORMING RODS) PNEUMONIA, PHARYNGITIS CELLULITIS STREPTOCOCCI ABSCESS SKIN & OTHER ORGANS STAPHYLOCOCCI COCCI DISEASE GENUS CHARACTERISTICS GRAM POSITIVE BACTERIA (COCCI/ RODS) CLASSIFICATION OF MEDICALLY IMPORTANT BACTERIA
  9. 9. GONORRHEA MENINGITIS NEISSERIA COCCI GRAM NEGATIVE BACTERIA (COCCI/RODS) NOCARDIOSIS NOCARDIA ACTINOMYCOSIS ACTINOMYCES FILAMENTOUS MENINGITIS LISTERIA DIPHTHERIA CORYNEBACTERIUM NON FILAMENTOUS NON-SPORE FORMING RODS CLASSIFICATION OF MEDICALLY IMPORTANT BACTERIA
  10. 10. BRUCELLOSIS BRUCELLA <ul><li>ZOONOTIC </li></ul><ul><li>ORGANISMS </li></ul>LEGIONELLA PNEUMONIA WHOOPING COUGH BORDETELLA MENINGITIS HAEMOPHILUS <ul><li>RESPIRATORY </li></ul><ul><li>ORGANISMS </li></ul>STRAIGHT RODS ( RESPIRATORY/ZOONOTIC/ENTERIC) DISEASE GENUS CHARACTERISTICS ANAEROBIC RODS AEROBIC RODS FACULTATIVE RODS (STRAIGHT/ CURVED) GRAM NEGATIVE RODS
  11. 11. PNEUMONIA KLEBSIELLA ENTEROCOLITIS TYPHOID SALMONELLA UTI ENTEROBACTER UTI, DIARRHEA ESCHERICHIA <ul><li>ENTERIC & RELATED ORG. </li></ul>PLAGUE YERSINIA CELLULITIS PASTEURELLA TULAREMIA FRANCISELLA ZOONOTIC DISEASE GENUS CHARACTERISTIC
  12. 12. TB, LEPROSY MYCOBACTERIUM ACID FAST BACTERIA PERITONITIS BACTEROIDES ANAEROBIC RODS UTI, PNEUMONIA PSEUDOMONAS AEROBIC RODS CHOLERA VIBRIO GASTRITIS, PEPTIC ULC HELICOBACTER ENTROCOLITIS CAMPYLOBACTER CURVED F. RODS DISEASE GENUS CHARACTERISTC
  13. 13. CLASSIFICATION OF MEDICALLY IMPORTANT BACTERIA RIGID THICK-WALLED CELLS FREE LIVING (EXTRACELLULAR ) NON FREE LIVING (OBLIGATE INTRACELLULAR PARASITES)
  14. 14. URETHRITIS, TRACHOMA, PSITTACOSIS CHLAMYDIA ROCKY MOUNTAIN SPOTTED FEVER RICKETSSIA DISEASE GENUS CHARACTERISTIC NON FREE LIVING (OBLIGATE INTRACELLULAR PARASITES)
  15. 15. CLASSIFICATION OF MEDICALLY IMPORTANT BACTERIA BACTERIA RIGID THICK-WALLED CELLS FLEXIBLE, THIN-WALLED CELLS WALL-LESS CELLS
  16. 16. LYME DISEASE BORRELIA LEPTOSPIROSIS LEPTOSPIRA SYPHILIS TREPONEMA DISEASE GENUS FLEXIBLE, THIN WALLED CELLS (SPIROCHETES )
  17. 17. PNEUMONIA MYCOPLASMA DISEASE GENUS WALL-LESS BACTERIA
  18. 18. Definitions <ul><li>Epidemiology </li></ul><ul><ul><li>The study of the transmission of disease </li></ul></ul><ul><li>Communicable Disease </li></ul><ul><ul><li>A disease that can be transmitted from one individual to another </li></ul></ul><ul><li>Contagious Disease </li></ul><ul><ul><li>A communicable disease that is easily spread from one individual to another </li></ul></ul><ul><li>Noncommunicable Disease </li></ul><ul><ul><li>A disease that is not transmitted from one individual to another </li></ul></ul>
  19. 19. III. A. Definitions <ul><li>Epidemic Disease </li></ul><ul><ul><li>A disease condition present in a greater than usual percentage of a specific population </li></ul></ul><ul><li>Pandemic Disease </li></ul><ul><li>Endemic Disease </li></ul><ul><ul><li>A disease condition that is normally found in a certain percentage of a population </li></ul></ul><ul><ul><li>An epidemic affecting a large geographical area; often on a global scale </li></ul></ul>
  20. 20. III. A. Definitions <ul><li>Reservoir of Infection </li></ul><ul><ul><li>The source of an infectious agent </li></ul></ul><ul><li>Carrier </li></ul><ul><ul><li>An individual who carries an infectious agent without manifesting symptoms, yet who can transmit the agent to another individual </li></ul></ul><ul><li>Fomites </li></ul><ul><ul><li>Any inanimate object capable of being an intermediate in the indirect transmission of an infectious agent </li></ul></ul>
  21. 21. III. A. Definitions <ul><li>Animal Vectors </li></ul><ul><ul><li>An animal (nonhuman) that can transmit an infectious agent to humans </li></ul></ul><ul><ul><li>Two types: mechanical and biological </li></ul></ul><ul><ul><ul><li>Biological animal vectors: The infectious agent must incubate in the animal host as part of the agent’s developmental cycle; eg, the transmission of malaria by infected mosquitoes </li></ul></ul></ul><ul><ul><ul><li>Mechanical animal vectors: The infectious agent is physically transmitted by the animal vector, but the agent does not incubate or grow in the animal; eg, the transmission of bacteria sticking to the feet of flies </li></ul></ul></ul>
  22. 22. GRAM POSITIVE COCCI <ul><li>GENUS </li></ul><ul><li>STAPHYLOCOCCI </li></ul><ul><li>STREPTOCOCCI </li></ul><ul><li>GENERAL PROPERTIES </li></ul><ul><li>NON MOTILE, NON SPORE-FORMING </li></ul><ul><li>STAPHYLOCOCCI: CATALASE POSITIVE </li></ul><ul><li>IN CLUSTER </li></ul><ul><li>STREPTOCOCCI : CATALASE NEGATIVE </li></ul><ul><li>IN CHAINS </li></ul>
  23. 23. STAPHYLOCOCCI
  24. 24. INTRODUCTION <ul><li>Staphyloccocci - derived from Greek “stapyle” (bunch of grapes) </li></ul><ul><li>Gram positive cocci arranged in clusters </li></ul><ul><li>Hardy organisms surviving many non physiologic conditions </li></ul><ul><li>Include a major human pathogen and skin commensals </li></ul>
  25. 26. Grouping for Clinical Purposes <ul><li>1. Coagulase positive Staphylococci </li></ul><ul><ul><li>Staphylococcus aureus </li></ul></ul><ul><li>2. Coagulase negative Staphylococci </li></ul><ul><ul><li>Staphylococcus epidermidis </li></ul></ul><ul><ul><li>Staphylococcus saprophyticus </li></ul></ul>
  26. 27. A. Staphylococcus aureus <ul><li>Major human pathogen </li></ul><ul><li>Habitat - part of normal flora in some humans (nose , sometimes skin esp hospital staff and patients, vagina of 5% females) and animals </li></ul><ul><li>Source of organism - can be infected human host, carrier, fomite or environment </li></ul>
  27. 28. DISEASES <ul><li>Due to direct effect of organism </li></ul><ul><ul><li>Local lesions of skin </li></ul></ul><ul><ul><li>Deep abscesses </li></ul></ul><ul><ul><li>Systemic infections </li></ul></ul><ul><li>Toxin mediated </li></ul><ul><ul><li>Food poisoning </li></ul></ul><ul><ul><li>toxic shock syndrome </li></ul></ul><ul><ul><li>Scalded skin syndrome </li></ul></ul>
  28. 29. IMPORTANT PROPERTIES <ul><li>Gram positive cocci, arranged in clusters </li></ul><ul><li>Non spore forming, non motile </li></ul><ul><li>Catalase positive (breaks H2O2 into O2 & H2O) </li></ul><ul><li>S. aureus: Coagulase positive, Hemolytic, Ferments Mannitol. </li></ul><ul><li>Plasmid mediated Antibiotic resistance in S. aureus </li></ul><ul><li>Cell wall components of S. aureus </li></ul>
  29. 30. Cell wall components & antigens of S.aureus <ul><li>Protein A (binds to Fc portion of Ig G at complement binding site) </li></ul><ul><li>Teichoic acid (adherence, antibody formation) </li></ul><ul><li>Microcapsule (11 serotypes) </li></ul><ul><li>Peptidoglycan has endotoxin-like properties. </li></ul>
  30. 31. Factors predisposing to S. aureus infections <ul><li>Host factors </li></ul><ul><ul><li>Breach in skin </li></ul></ul><ul><ul><li>Chemotaxis defects </li></ul></ul><ul><ul><li>Opsonisation defects </li></ul></ul><ul><ul><li>Neutrophil functional defects </li></ul></ul><ul><ul><li>Diabetes mellitus </li></ul></ul><ul><ul><li>Presence of foreign bodies </li></ul></ul><ul><li>Pathogen Factors </li></ul><ul><ul><li>Catalase (counteracts host defences) </li></ul></ul><ul><ul><li>Coagulase </li></ul></ul><ul><ul><li>Hyaluronidase </li></ul></ul><ul><ul><li>Lipases (Imp. in disseminating infection) </li></ul></ul><ul><ul><li>B lactasamase(ass. With antibiotic resistance) </li></ul></ul>
  31. 32. Factors predisposing to S. aureus infections <ul><li>Toxins produced by S. aureus </li></ul><ul><li>Enterotoxin </li></ul><ul><li>Toxic shock syndrome toxin (TSST is a super antigen) </li></ul><ul><li>Exfoliatin (epidermolytic) </li></ul><ul><li>Leucocidins </li></ul><ul><li>Alpha toxin (tissue necrosis) </li></ul><ul><li>Staphylokinase </li></ul>
  32. 33. SKIN LESIONS (Pyogenic) <ul><li>Styes </li></ul><ul><li>Furuncles(infection of hair follicle) </li></ul><ul><li>Carbuncles (infection of several hair follicles) </li></ul><ul><li>Wound infections(progressive appearance of swelling and pain in a surgical wound after about 2 days from the surgery) </li></ul><ul><li>Impetigo(skin lesion with blisters that break and become covered with crusting exudate) </li></ul><ul><li>Cellulitis </li></ul>
  33. 34. IMPETIGO
  34. 35. SYMPTOMS OF STAPH INFECTIONS <ul><li>The symptoms of a staph infection depends on where the infection is. The staph bacteria can cause: </li></ul><ul><li>Boils – an abscess, bump, or swelling within the skin. Also called a furuncle. </li></ul>
  35. 36. <ul><li>Cellulitis – a “flat” skin infection which can make the skin red, painful and warm but does not have pustules. </li></ul>
  36. 37. <ul><li>Folliculitis – an infection of the hair follicles </li></ul>
  37. 38. <ul><li>Impetigo – pustules (bulbous impetigo) or honey colored crusted lesions on the skin </li></ul>
  38. 41. Staphylococcol Infection
  39. 42. DEEP ABSCESSSES <ul><li>Can be single or multiple </li></ul><ul><li>Breast abscess can occur in 1-3% of nursing mothers in puerperium </li></ul><ul><li>Can produce mild to severe disease </li></ul><ul><li>Other sites - kidney, brain from septic foci in blood </li></ul>
  40. 43. Systemic Infections <ul><li>1. With obvious focus </li></ul><ul><ul><li>Osteomyelitis, septic arthritis </li></ul></ul><ul><li>2. No obvious focus </li></ul><ul><ul><ul><li>heart (infective endocarditis) </li></ul></ul></ul><ul><ul><ul><li>Brain(brain abscesses) </li></ul></ul></ul><ul><li>3. Ass. With predisposing factors </li></ul><ul><ul><li>multiple abscesses, septicaemia (IV drug users) </li></ul></ul><ul><ul><li>Staphylococcal pneumonia (Post viral) </li></ul></ul>
  41. 44. B. TOXIN MEDIATED DISEASES <ul><li>1. Staphylococcal food poisoning </li></ul><ul><ul><li>Due to production of entero toxins </li></ul></ul><ul><ul><li>Superantigen – IL-1 & 2 </li></ul></ul><ul><ul><li>heat stable entero toxin acts on gut </li></ul></ul><ul><ul><li>produces severe vomiting, non bloody diarrhea following a very short incubation period </li></ul></ul><ul><ul><li>Resolves on its own within about 24 hours </li></ul></ul>
  42. 45. 2. Toxic shock syndrome <ul><li>High fever, diarrhoea, shock and erythematous skin rash which desquamate </li></ul><ul><li>Mediated via ‘toxic shock syndrome toxin’– super antigen </li></ul><ul><li>10% mortality rate </li></ul><ul><li>ass. With young women using tampones during menstruation & wound infection </li></ul>
  43. 47. 3. Scalded skin syndrome <ul><li>Disease of young children </li></ul><ul><li>Mediated through minor Staphylococcal infection by ‘epidermolytic toxin’ producing strains </li></ul><ul><li>Mild erythema and blistering of skin followed by shedding of sheets of epidermis </li></ul><ul><li>Children are otherwise healthy and most eventually recover </li></ul>
  44. 48. S. aureus -- Kawasaki syndrome <ul><li>Unknown etiology </li></ul><ul><li>Vasculitis of medium & small sized arteries. </li></ul><ul><li>Strawberry tongue </li></ul>
  45. 49. DIAGNOSIS <ul><li>1. In all pus forming lesions </li></ul><ul><ul><li>Gram stain and culture of pus </li></ul></ul><ul><li>2. In all systemic infections </li></ul><ul><ul><li>Blood culture </li></ul></ul><ul><li>3. In infections of other tissues </li></ul><ul><ul><li>Culture of relevant tissue or exudate </li></ul></ul>
  46. 50. Diagnosis <ul><li>Gram Stain: Gram positive cocci in clusters </li></ul><ul><li>Yellowish colonies , b-hemolytic on Blood agar </li></ul><ul><li>Catalase and coagulase positive </li></ul><ul><li>Mannitol fermenter </li></ul>
  47. 51. Antibiotic sensitivity pattern <ul><li>Very variable and not predictable </li></ul><ul><li>Very imp. In Pt. Management </li></ul><ul><li>Mechanisms </li></ul><ul><ul><li>1.B lactamase production - plasmid mediated </li></ul></ul><ul><ul><ul><li>Has made S. aureus resistant to penicillin group of antibiotics - 90% of S. aureus (Gp A) </li></ul></ul></ul><ul><ul><ul><li>B lactamase stable penicillins (cloxacillin, oxacillin, methicillin) used </li></ul></ul></ul><ul><ul><li>2. Alteration of penicillin binding proteins </li></ul></ul><ul><ul><ul><li>(Chromosomal mediated) </li></ul></ul></ul><ul><ul><ul><li>Vancomycin is the drug of choice </li></ul></ul></ul><ul><ul><ul><li>MRSA, NRSA, VISA </li></ul></ul></ul>
  48. 52. <ul><li>Tested in lab using methicillin </li></ul><ul><li>Referred to as methicillin resistant S. aureus (MRSA) </li></ul><ul><li>Emerging problem in the world </li></ul><ul><li>In Sri Lanka prevalence varies from 20- 40% in hospitals </li></ul><ul><li>Drug of choice - vancomycin </li></ul><ul><li>In Japan emergence of VIRSA (vancomycin intermediate resistant S. aureus) </li></ul><ul><li>No effective antibiotics discovered -We might have to discover </li></ul>
  49. 53. 2. Staphylococcus epidermidis <ul><li>Skin commensal </li></ul><ul><li>Has predilection for plastic material </li></ul><ul><li>Ass. With infection of IV lines, prosthetic heart valves, shunts </li></ul><ul><li>Causes urinary tract infection in cathetarised patients </li></ul><ul><li>Has variable ABS pattern , highly resistant </li></ul><ul><li>Treatment should be aided with ABST </li></ul><ul><li>Hospital acquired </li></ul><ul><li>Novobiocin sensitive </li></ul>
  50. 54. 3. Stapylococcus saprophyticus <ul><li>Skin commensal </li></ul><ul><li>Imp. Cause of UTI in sexually active young women </li></ul><ul><li>Usually sensitive to wide range of antibiotics </li></ul>
  51. 55. GRAM POSITIVE COCCI S. aureus  hemolytic mannitol yellow + - Staphylococcus (Clusters) Streptococcus (pairs & chains) Catalase BETA: Bacitracin S. pyogenes (group A) CAMP/ Hippurate S. agalactiae (group B) Hemolysis Coagulase S. epidermidis nonhemolytic (usually) mannitol white ALPHA: Optochin /Bile Solubility S. pneumoniae GAMMA: Bile Esculin 6.5% NaCl Group D* Enterococcus Bile Esculin 6.5% NaCl Group D* Non- Enterococcus (*can also be alpha hemolytic) Note: S. viridans is Is alpha hemolytic and negative for all the tests below below + + + + + + + - - Summary Figure (Identification Scheme)

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