Chapter 28: Neisseriaceae

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Chapter 28 Neisseriaceae

• Gram negative diplococci
• Two primary pathogens
• Neisseria gonorrhoeae, Neisseria meningitidis
• Fastidious, obligate aerobes, often capnophilic

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Neisseria gonorrhoeae

• XMT sex, other close contact (eyes)
• VF pili (adhesins)
• Protein II (Opa) helps attach, penetrate cells
• Protein I (Por), Protein III make pores in cell
• Endotoxin (LOS) ? inflammation
• IgA protease destroys antibodies
• ?-lactamase (penicillinase) PPNG
• Antigenic variation (esp. pili)

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Gonorrhea

• SS women often asymptomatic
• Dysuria, urethral discharge
• Usually localized dissemination ? abscesses,
  PID, arthritis
• Ophthalmia neonatorum ? blind babies
• Dx specimen GS and culture
• GS GNID diagnostic in males
• gt 90 sensitive, 98 specific

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Gonorrhea

• Confirm Dx by culture
• Selective enriched medium (MTM, NYC)
• Thayer-Martin chocolate agar antibiotics
• Incubate in 5-10 CO2
• ID GS, oxidase, sugar oxidation (CTA sugars)
• DNA probe sensitive, specific, fast
• Trt mostly R to penicillins
• Ceftriaxone, ciprofloxacin, etc. - test
• No vaccines no immunity to repeat infection

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Neisseria meningitidis

• Three main VF
• Capsule
• Endotoxin (LOS) causes most of damage
• Pili
• XMT resp. route close contacts
• Diseases meningitis, septic shock
• SS headache, high fever, rash ? petechial
  hemorrhage ? hemorrhagic bullae
• DIC (disseminated intravascular coagulation)

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Dx Meningococcal Disease

• GS important in meningitis GNID
• Culture BAP, chocolate (grows on MTM)
• ID test gonorrhea
• Trt antibiotics (mostly S to penicillin)
• Vaccine available for common serotypes
• Natural immunity after infection

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Other G- Diplococci

• Neisseria lactamica
• Non-pathogenic
• Grows on MTM looks like gc / mgc
• May be isolated from NP, genital, other sites
• Oxidizes lactose in CTA medium
• Moraxella catarrhalis
• Opportunistic pathogen pneumonia, otitis, etc.
• Looks like Neisseria
• Negative in CTA DNAse

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Moraxella catarrhalis in sputum