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What are the general characteristics of Neisseria spp?
- Gram negative
- Diplococcus
- coffee bean shape
- Aerobic, capnophilic (require CO2)
- Non-motile
- catalase positive
- oxidase positive
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What Neisseria are commensal w/ location? Pathogenic?
- Commensal: N. lactamica - nasopharynx of children (often mistaken for N. meningitids)
- N. sicca - respiratory tract adults
- N. elongata - upper respiratory tract
- Pathogenic: N. gonorrhoeae
- N. meningitides
- Moraxella catarrhalis
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What makes collecting Neisseria specimens difficult sometimes?
- sensitive to temp fluctuations and dry conditions
- Dacron/rayon swabs are recommended
- must be kept at room temp (cold sensitive)
- Specs. should be kept moist until culture
- *high CO2 needed for N. gonorrhoeae transport
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Chocolate II agar - use and ingredients
- Isolation and cultivation of Neisseria and Haemophilus spp (and other fastidious bacteria)
- Ingredients: Gonococci agar base
- hemoglobin solution
- supplement VX/IsoVitaleX
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Modified Theyer MArtin Agar - use and ingredients
- Selective for N. gonorrheae: isolates from specimen contain mixed flora
- Ingredients: chocolate agar base
- enriched with hgb and supplement B
- VCNT antibiotic soln added (gives the selectivity)
- Vancomycin, Colistin, Nystatin, Trimethroprim lactate
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Martin-Lewis agar - use and ingredients
- selective for N. gonorrhoeae: isolates from specimen contain mixed flora
- ingredients: gonococci agar base
- hemoglobin
- Supplement solution/IsoVitaleX
- VCAT inhibitor (Vancomycin, Colistin, Anisomycin, Trimethoprim)
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New York City agar - use and ingredients
- isolation of pathogenic Neisseria
- ingredients: NYC basal medium (agar, cornstarch)
- horse or cow blood cells
- Horse plasma, citrated
- yeast dialysate
- glucose soln
- VCNT antibiotic soln
- Vancomycin, colistin, nystatin, trimethoprim
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What are the diagnostic tests for Neisseria
- Growth on special media: MTM, NYC, SBA, choc
- Rapid fermentation: glucose, maltose, lactose
- Cytochromse oxiadase test
- Nitrate reduction
- Superoxol test (30% peroxide)
- Nucleic acid testing: PCR for specific genes (23S rRNA, 16S rRNA), probe assays
- highly specific AND sensitive
- *NOTE -almost every lab uses or sends out
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Neisseria gonorrhoeae - AKA, diseases
- AKA Gonococcus (GC)
- diseases: purlent urethrits (males)
- cervicits (females)
- pharyngitis and anorectal infections
- conjuctivitis (mother -> bby)
- disseminated infection to other sites including joints
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Neisseria gonorrhoeae - differences between men and women
- Men: 95% show symptoms of acute infection (dysuria, urethral discharge)
- Women: most infections asymptomatic
- 40-60% may have urethral infection
- Complications of vaginal accessory glands, pelvic inflammatory disease, Fitz-Hugh-Curtis syndrome, perihepatitis
- Gonococcal opthalmia to newborns
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What are the virulence factors of Neisseria gonorrhoeae?
- Receptors for human transferrin
- capsule
- pili
- cell membrane proteins
- lipooligosaccharide (LOS) or endotoxin
- IgA protease
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Neisseria gonorrhoeae ID - microscopic appearance, plating, morphology
- Gram stain (coffee-bean shaped diplococci)
- gram neg inside PMNs is diagnostic for symptomatic males
- not for females, because some Neisseria spp are normal flora
- ALWAYS report presence of neutrophils (PMNs) because it indicates infection
- Plating: sheep's blood agar, chocolate, MTM, ML, NYC
- *culture media incubated at 35-37C in humid, 3-5% CO2 atmosphere
- morphology: small grayish white convex shiny colonies
- smoother or irregular margins
- u to 5 different colony types on primary plate!
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Neisseria gonorrhoeae - antibiotic resistance
- Cetriaxone or qunolones are usually effective
- Macrolides are effect
- B-lactimase is common (detect w/ spot test)
- resistance to quinolones is emerging
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Neisseria gonorrhoeae - why is it important to public health
- marker for increased transmission of other STDs
- concomitant infection with C. trachomatis can occur
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Neisseria meningitidis - diseases
- Meningitis: acute, purulent, associated w/ petichial rash
- rapidly fatal
- highly contagious
- waterhouse-Friderichsen syndrome: bleeding into adrenal glands = inability to maintain blood pressure during septic shock (children)
- Acute meningococcemia: in blood stream, not yet CSF
- high mortality rate
- Pneumonia
- Conjunctivits, sinusitis, otitis media
- hemmorhagic lesions
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Neisseria meningitids - transmission, virulence factors
- transmission: person-to-person by contaminated resp. droplets (VERY CONTAGIOUS)
- v factors: capsular polysaccharides prevent phago
- lipooligosaccharadies play role in lysis of neutrophils and epithelial cells
- pili and fimbriae enable binding to human cells
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bacterial meningitis serological group distribution
- A: pandemics
- B & C: predominantly in USA
- G: community-aquired
- Y: meningococcal pneumonia
- W-135: invasive disease
- *NOTE - vaccines available for A and B
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Neisseria meningitidis - specimen collection
- CSF: centrifuge and use sediment for gram stain
- USE TUBE #3
- Blood cultures
- N-P swabs: plated immediately or PROPER t.port media
- (5-10% pop carry as normal flora 0.o)
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Neisseria meningitidis - plating and colony morphology
- 5% SBA and chocolate
- increased CO2 required for optimal growth
- high humidty required
- morphology: medium smooth round moist gray-to-white encapsulated strains (MUCOID)
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Neisseria meningitidis - gram stains
- diplococci
- bad news if found in CSF! Report immediately
- fount intra and extra cellulary near PMNs in blood (and CSF?)
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Why is Neisseria meningitidis a public health issue?
- Must be reported
- All contacts must be traced and treated (aerosal transmission)
- spreads quickly in crowded conditions
- 5-10% of population are carriers
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Neisseria meningitids - biochem? acid from? isolated on?
- oxidase positive
- acid from glucose and maltose
- isolated on sheep blood or chocolate agar
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Moraxella catarrhalis - AKA, microscopic appearance, presumptive ID
- AKA: used to be N. catarrhalis
- Micro: gram neg diplococci, INTRACELLULAR
- presumptive: collected from eye/ear culture
- gram neg diplococci
- DNase positivehydrolyzes tributryin
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Moraxella catarrhalis - disease
- Respiratory infections: one of the "big three" for bacterial pneumonia in adults
- otitis media
- sinusitis
- lower resp tract infections in elderly and COPD
- rarely casues disseminated bacterermia, meningitis
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Moraxella catarrhalis - plating and morphology
- Grows well on 5% SBA
- morph: large, non-pigmented/gray, opaque, smooth
- hockey puck: colony moves intact over agar surface
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Moraxella catarrhalis - biochem ID, antibiotic res, collection
- biochemical ID: hydrolyzes tributyrin
- reduces nitrate
- cannot produce acid from carbs
- resis: B-lactams effective with lactamase inhibitor
- macrolides, cephalosporins, SXT, quinolones effective
- Collect: NO SPECIAL REQUIREMENTS!
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