USMLE

Neisseria spp: Overview

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Bacteria - Gram Negative
  1. Neisseria spp: Overview
  2. Neisseria gonorrhoeae
  3. Neisseria meningitidis
  4. Haemophilus influenzae
  5. Bordetella pertussis
  6. Brucella
  7. Legionella pneumophila
  8. Pseudomonas aeruginosa: Overview
  9. Pseudomonas aeruginosa: Disease
  10. Salmonella Overview
  11. Salmonella typhi
  12. Salmonella enteritidis
  13. Shigella
  14. Yersinia enterocolitica
  15. Escherichia coli: Overview
  16. Enterohemorrhagic E. Coli (EHEC)
  17. Enterotoxigenic E. Coli (ETEC)
  18. Klebsiella pneumoniae
  19. Campylobacter jejuni
  20. Vibrio spp.
  21. Helicobacter pylori
  22. Borrelia burgdorferi (Lyme Disease)
  23. Leptospira interrogans
  24. Treponema pallidum: Overview
  25. Treponema pallidum: Diagnosis
  26. Congenital syphilis
  27. Chlamydia: Overview
  28. Chlamydia trachomatis
  29. Chlamydia pneumoniae vs. psittaci
  30. Rickettsia rickettsii
  31. Rickettsia typhi vs. prowazekii
  32. Anaplasma vs. Ehrlichia
  33. Coxiella burnetii (Q fever)

Neisseria spp.

  • Includes:
    • Neisseria gonorrhoeae
    • Neisseria meningitidis
  • Gram-negative diplococci
    • Contain lipooligosaccharides (LOS) with strong endotoxin activity
  • Facultatively intracellular
    • Often visualized within epithelial cells
  • Grows on Thayer-Martin agar
    • Selective chocolate (heated-blood) agar-based medium containing the antibiotics vancomycin, colistin, nystatin and trimethoprim
    • Prevents growth of microbes other than Neisseria
  • Produce IgA protease
    • Cleave IgA at hinge region, impairing its function at mucosal surfaces
    • Improves mucosal adherence
  • Increased risk with terminal complement deficiency (C5-C9)
    • Inability to generate membrane attack complex (MAC) leads to poor clearance of bacteria
  • Pili
    • Hair-like proteins that facilitates attachment to mucosal surfaces
      • Nasopharynx for N. meningitidis, vaginal/urethral for gonorrhoea
    • No vaccine due to antigenic variation of pilus proteins 
  • Disseminated infections present with petechial skin rash
    • Due to small-vessel vasculitis