Corynebacterium

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Corynebacterium

  1. 1. Corynebacterium Gram + bacilli
  2. 3. <ul><li>Non acid fast-non motile-irregularly stained segments- </li></ul><ul><li>Shows club shaped swellings-coryne=club </li></ul><ul><li>Most imp member-C.diphtheria </li></ul><ul><li>Diphtheros=leather –tough leathery psuedomembrane formed in this disease </li></ul><ul><li>Also known as kleb’s-loeffler bacillus/KLB </li></ul>
  3. 4. Corynebacterium diphtheria
  4. 5. <ul><li>Pleomorphic-nonsporing-noncapsulated-nonmotile </li></ul><ul><li>Granules-Babes Ernest granules/volutin granules/polar bodies-polymetaphosphate </li></ul><ul><li>Often arranged in small groups,the bacilli arranged at various angles to each other,arranged in V / L -Chinese letter/cuniform arrangement </li></ul><ul><li>Due to incomplete seperation of daughter cells, after binary fission </li></ul>
  5. 6. <ul><li>Loeffler’s methylene blue-stains bluish purple in colour-diagnostic </li></ul><ul><li>Mcload’s classsification- gravis(severe),intermedius,mitis(mild) </li></ul><ul><li>Paralytic complications-gravis </li></ul><ul><li>Haemorragic complications-intermedius </li></ul><ul><li>Mitis-obstructive complications </li></ul>
  6. 7. Toxin <ul><li>Powerful exotoxin-can b toxoided </li></ul><ul><li>Two fragments- A and B </li></ul><ul><li>A –enzymatic activity </li></ul><ul><li>B-binding to cell membrane </li></ul><ul><li>A enters cyto---activated by proteases--- inactivate elongation factor 2 —inhibits protein synthesis—cell death </li></ul><ul><li>Effect depends on concentration of Fe </li></ul><ul><li>Spacial affinity for myocardium,adrenals,nerve endings </li></ul>
  7. 8. Toxoid <ul><li>Has lost toxigenicity, but not antigenicty </li></ul><ul><li>Vaccine prep </li></ul><ul><li>Park William 8 strain-universally used strain </li></ul><ul><li>Genetic information for toxin production is given by presence of Corynephages(toxin+) –toxigenicity remains aslong as the bacilli is in lysogenic phase </li></ul><ul><li>Infection with beta phage-lysogenic/phage conversion </li></ul>
  8. 9. Epidemiology <ul><li>d/s of children </li></ul><ul><li>Checked by immunisation </li></ul><ul><li>Peak in 2-5 yrs </li></ul><ul><li>Source-cases+nasal carriers </li></ul><ul><li>Route-person to person by inhalation-rarely fomites </li></ul><ul><li>Incubation period -3-4 days </li></ul>
  9. 10. Types of diphtheria <ul><li>Faucial-commonest </li></ul><ul><li>Laryngeal </li></ul><ul><li>Nasal </li></ul><ul><li>Otitic </li></ul><ul><li>Conjunctival </li></ul><ul><li>Genital </li></ul><ul><li>cutaneous </li></ul>
  10. 11. Types of clinical severity <ul><li>Malignant /hypertoxic-menmbrane+lymphadenitis+toxemia+bull neck+circulatory failure+paralysis in recoveries </li></ul><ul><li>Septic-ulceration, cellulitis around pseudo membrane </li></ul><ul><li>Haemorrhagic-bleeding tendency </li></ul>
  11. 12. Complications <ul><li>Asphyxia –due to pseudomembrane </li></ul><ul><li>Acute circulatory failure </li></ul><ul><li>Post diphtheritic paralysis </li></ul><ul><li>Pnemonia and otitis media </li></ul><ul><li>Diphtheria---enters via inhalation---in faucial area---multiplies---toxin---necrotic changes--- degraded tissue+disintegrating epithelial cells+rbc+wbc+bacteria+fibrinous exudate=pseudoimembrane </li></ul>
  12. 13. Lab d/g <ul><li>Clinical d/g is more imp-in lab- just confirmation </li></ul><ul><li>Isolation(swab-pharynx,cutaneous) and demonstration of toxins </li></ul><ul><li>Microscopic appearance-but as it can b seen as commensal-diphtheroids-not d/g </li></ul>
  13. 14. Culture <ul><li>Loeffler’s serum slope---needs enriched media </li></ul><ul><li>Tellurite blood agar-selactive medium for CBD-turns black in colour </li></ul>
  14. 15. Virulence tests <ul><li>To demonstrate toxigenicity-in vivo & invitro </li></ul><ul><li>Invivo- animal inoculation-guinea pigs/rabbits---s/c or intra cutaneous </li></ul><ul><li>Invitro tissue culture </li></ul>
  15. 16. Sub cutaneous test <ul><li>8-12 hrs before given antitoxin 500 u—survives </li></ul><ul><li>Unprotected dies in 4 days </li></ul><ul><li>Autopsy reveals the d/s </li></ul>
  16. 17. Intracutaneous test <ul><li>Adv-test wont die </li></ul><ul><li>Inject bacterial suspension + 50u antitoxin intraperitoneally 4hrs after test—inflammation progressing to necrosis in 48 -72 hrs </li></ul><ul><li>As many as 10 strains can b tested in one rabbit at a time </li></ul>
  17. 18. Invitro test
  18. 20. Elek’s gel precipitation tests <ul><li>Anti toxin-1000 u/ml </li></ul><ul><li>20% normal horse serum agar is used </li></ul>
  19. 21. Treatment <ul><li>Penicilline D is the drug of choice </li></ul><ul><li>If the d/s sets in Start with anti diphtheritic serum—high dose iv—20’000-1 lakh u </li></ul><ul><li>Maintain the airway </li></ul>
  20. 22. Prophylaxis <ul><li>Active immunisation-as DPT vaccine-3 doses at 6,10,14 weeks + a booster dose 1 yr later + second booster dose at school entry </li></ul><ul><li>Passive immunisation-to contactsanti diphtheria serum s/c-500-1000 u </li></ul><ul><li>Combined immunisation </li></ul>
  21. 23. Other coryne bacteria <ul><li>CB.jeikeium-in immunocompramised-multiple antibiotic resistant—vancomycin </li></ul><ul><li>CB psuedo TB- </li></ul><ul><li>CB minutissimum-erithrasma-localised infection of stratum corneum of axilla and groin </li></ul><ul><li>Diphtheroids- normal commensals </li></ul>

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