Unit 3 - Gram Negative Cocci Flashcards
Neiseriaceae family shape
GN Diplococci
or
Short GNR
Family Neisseriaceae Oxidase result
Positive
Family neisseriaceae Catalase results
Positive
EXCEPT Kingella & Eikenella
Are Neisseriaceae fastidious or non fastidious?
Fastidious
except kingella
Are Neisseria normal flora as a whole?
Some are, others aren’t
Neisseriaceae Virulence factors
Capsule
Pili
Cell wall proteins
Endotoxin
IgA protease
Sometimes when you take meds while having a neisseriaceae infection, it can hurt. Why?
Endotoxins release upon death
What is the predominant host response with a Neisseriaceae infection?
PMN
Neisseria spp. diseases caused
Gonorrhea
Miningitis
Meningococcemia
DGI
Gonococcal arthritis
Otitis media
Sinusitis
Pathogenic Neisseria family colonies appear how on a plate?
Non pigmented
What are the non-pigmented Neisseria family?
N. gonorrhoeae
N. meningitides
N. weaveri
Normal flora Neisseria appear how on a plate?
Pigmented
What are the pigmented Neisseria
N. lactamica
N. sicca
Moraxella catarrhalis
Is N. gonorrhoeae ever normal flora?
No, strict pathogen
Where is N. gonorrhoeae found in?
only humans
Where on the body can gonorrhea be isolated?
Anus
Eyes
Throat
Blood
Private parts
What are the male complications in male gonorrhea
Epididymitis
Urethral stricture
Prostatitis
Female gonorrheal complications
PID
Sterility
Manifestations of Gonorrhea
DGI
Ophthalmia neonatorum
Asymptomatic genital infections
What causes DGI?
Gonorrhea caused by AHU strains
(Arginine, hypoxanthine, uracil)
How common is DGI in gonnorhea patients?
<3%
What percentage of females are asymptomatic for gonorrhea?
About 50%
How is GC a delicate organism?
Fastidious
Specimen collection requirements for GC
Dacron or rayon swab
Enriched agar with CO2
Must be kept warm
Transport media for GC
JEMBEC
What is JEMBEC
Chocolate agar w antibiotics
Small plastic compact with CO2 tablet
Streaked in W with swab then across with loop
What kind of agar does GC require
Chocolate agar
What is in Chocolate agar?
Enriched base
Hemoglobin
NAD (Nicotinamide adenine dinucleotide)
What mimics NAD?
IsoVitaleX
Why must selective agar be used when plating GC?
Inhibits normal flora
What selective agars are used for GC?
Thayer Martin
Modified Thayer Martin
Martin Lewis
NYC medium
What is Thayer Martin plate
Chocolate agar
Vancomycin, colistin, nystatin
What is modified Thayer martin
Thayer Martin plus trimethoprim
What is Martin lewis
Chocolate agar
Vancomycin, colistin, anisomycin (yeast), trimethoprim
What is NYC medium
Horse blood yeast extract
Similar antibiotics as MTM
If clinical site has no normal flora, what plate should you use?
Plain chocolate agar
If the clinical site has no normal flora, what plate do you use?
Chocolate agar
What clinical sites have no normal flora?
Synovial fluid
CSF
How does GC appear on a plate?
SMall
Translucent
No pigment
Some variation in colonies of the same strain
How do colonies of GC vary by size?
Corresponds to P antigen on surface
Types T1-T5
How old should GC be for biochemical testing?
Young, organisms will autolyze as it continues growing
Expected test results for GC
Oxidase positive
Catalase postiive
Uses glucose only
What is the definitive ID for GC?
Carbohydrate utilization tests
Is culture required for the ID of GC?
Not anymore
Treatment for GC
Ceftriaxone and Azithromycin
Why is GC resistant to penicillin?
Beta lactamases
Is Neisseria meningitides normal flora?
Can exist in a carrier state
Who is at risk for N. menigitides?
People living in close quarters
Which organism is quickly fatal if untreated?
N. meningitides
N. meningitides can cause ___ with or without ___
meningococcemia, menigitis
N. meningitides capsule types
A, B, C, Y, W-135
What are the pathologic mechanisms of N. menigitidis
Pili
Capsule
Endotoxin
IgA protease
Treatment for meningitis?
Penicillin
Someone with meningitis is allergic to penicillin, what are they given next?
Chloramphenicol
What is given as prophylaxis for meningitis?
Rifampin
What capsule types are people vaccinated to
A & C, W-135 & Y when young
Serotype B when older
Complications of Meningitis
DIC
Shock
Waterhouse-Friderichsen syndrome
What is Waterhouse friderichsen syndrome
Disseminated meningococcal infection with rash and hemorrhage in adrenals
Septic Shock in meningitis symptoms
Low oxygen and BP
Inc heart rate
What can cause septic shock that’s a GNC?
N. meningitis
What kind of environment is needed to grow N. meningitidis?
CO2
Warm and moist
How does N. meningitides appear on a plate?
Shiny & Non-pigmented
Test results for N. meningitides
oxidase pos
catalase pos
Glucose and maltose usage
What are useful tests for IDing Neisseria?
Chromogenic enzyme substrate testing
MALDI-TOF
carb utilization
N. meningitis on gram stain
Intracellular AND extracellular diplococci
Gram negative, but may resist decolorization and size variation
Which neisseria bug is isolated from dog bite wounds?
N. weaveri
Shape of N. weaveri
Short Gram Neg rod
What did N. weaveri used to be called
CDC group M5
Carb utilization for N. weaveri
None
Non-pathogenic Neisseria is normal flora of where?
URT
Female genital track
Where is Moraxella normal flora of?
URT
What does Moraxella cause?
Otitis media
Sinusitis
Gram stain of M. catarrhalis
Uniform size
may show tetrads
Where does M. catarrhalis grow?
SBA
Chocolate
A colony on a plate appears like a wagon wheel, what might this be?
M. catarrhalis
A colony slides across the plate like a hockey puck, what might this be?
M. catarrhalis
How to distinguish M. catarrhalis from Neisseria?
No sugar
DNase positive
Butyrate esterase positive
Butyrate esterase result in Neisseria
Neg
M. catarrhalis can produce ____ that makes it resistant to ___
Beta lactamase
Ampicillin or amoxicillin
Where is Kingella normal flora of
URT
How does Kingella appear on the agar
Like non pathogenic neisseria
Gram stain of Kingella
GNC with no water
GNR with water
How do you distinguish true gram stain shape of Kingella?
Incubation with penicillin disc
How does Kingella grow when around penicillin disc?
Grows as a rod
Catalase result of Kingella
Negative
Kingella is usually isolated in..?
Immunosuppressed patients
Where is Eikenella corrodes normal flora of?
Mouth and bowel
Oxidase result of Eikenella
Positive
Catalase result of Eikenella
Negative
How does Eikenella appear on stain?
More rod shaped than Neisseria
What does Eikenella need to grow?
CO2
Where is Eikenella isolated form
Human bite from punching teeth
Licking needle clean and shooting it up
What does eikenella do to the agar?
Pits the agar
What org smells like bleach?
E. corrodens