Staphylococcus and Micrococcus

35 cards

Staphylococcus and Micrococcus epidemiology, morphology, culture characteristics, diagnostic biochemical tests and serology.


 
  
Created Jan 9, 2011
by
biogirl10

 

 
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1
What is the Gram and microscopic arrangement of both staph and micrococcus?
 
Gram +Cocci in clusters, pairs or tetrads
2
Are staph and micrococcus catalase positive or negative?
 
Positive
3
What sites of infection are staph infections associated with?
 
various skin and mucosal surfaces when strain gains entrance to normally sterile site
4
Is S. aureus coagulase negative or positive?
 
Positive
5
What are 3 diseases associated with Staph aureus?
 
Impetigo - skin infectionScalded skin syndrome - affects babiesToxic shock syndrome - systemic
6
What 3 species of Staph are assoc. with nosocomial infections other than S. aureus?
 
S. epidermidisS. haemolyticusS. lugdunenis
7
Are S. epidermidus, S. haemolyticus, and S. lugdunenis coag neg or pos?
 
negative
8
What two characteristics of S. epidermidis enhances its likelihood of infection?
 
Its production of an exopolysaccharide that enhances attachment and its ability to acquire...
9
How is S. lugdunensis differentiated from other coag neg staph from sterile sites?
 
PYR pos and pos for ornithine decarboxylase
10
Why does S. lugdunensis need to be differentiated from other coag neg staph from sterile sites?
 
Because it has different interpretative criteria for oxacillin
11
What infection is S. saprophyticus most commonly assoc. with?
 
community acquired urinary tract infections in young sexually active females
12
What media can be used to cultivate staph and micrococcus?
 
5% sheep blood agar, Chocolate agar, broth blood cultures, Nutrient broths
13
What selective media is used to isolate staph?
 
Mannitol salt agar
14
What would a colony with a yellow halo on an MSA plate indicate?
 
that it is a staph colony that can ferment mannitol
15
What are the incubation conditions to cultivate staph on BAP, chocolate and MSA?
 
BAP and Chocolate - 35oC in CO2 or ambient air from 24 hrMSA 48-72 hr
16
What is the cultural characteristics of S. aureus on BAP?
 
med - large colonies, smooth, slightly raised, translucent, creamy yellowBeta hemolytic!
17
What are the cultural characteristics of S. epidermidis on BAP?
 
small - med colonies, translucent, gray-white, non or alpha hemolytic, sticky (slime producing)
18
What are the cultural characteristics of S. saprophyticus?
 
large, glossy, opaque, convex, Usually white  (can be yellow or orange)
19
What are the cultural characteristics of Micrococcus on BAP?
 
small - med, non-hemolytic, variety of pigments but usually yellow, opaque and...
20
What is the efffect of Lysostaphin on micrococcus versus staph?
 
Micrococcus - no lysisStaph - lysis
21
Are micrococcus and staph resistant or susceptible to furazolidone?
 
Micrococcus - resistantStaph - susceptible
22
Are micrococcus and staph resistant or susceptible to and A disc?
 
Micrococcus - susceptibleStaph - resistant
23
What are the oxidase reactions of micrococcus and staph?
 
micrococcus - posstaph - neg
24
Are micrococcus and staph aerobic, anaerobic, facultatively anaerobic, or microaerophilic?
 
Micrococcus - aerobicStaph - facultatively anaerobic
25
What is staph aureus's DNA hydrolysis rxn?
 
S. aureus - positive
26
What are the two coagulase tests?
 
Rapid slide test and tube test
27
What does a positive rapid slide test indicate?
 
bound coagulase - clumping factor
28
what does a positive tube coagulase test indicate?
 
free coagulase - clotting factor
29
What is S. intermedius assoc with?
 
dog bite wound infections?
30
What is S. intermedius most often confused with?
 
S. aureus
31
What are the characteristics of S. intermedius?
 
white - yellow, creamy opaque coloniescatalase and coagulase pos
32
When should coag negative staph be identified to species?
 
For normally sterile sites, isolates from prosthetic devices or catheters, isolates from urinary...
33
What serodiagnosis for staph can be done?
 
antibodies to teichoic acid - wall component of gram + bacteria
34
What antimicrobial susceptibilities might be run on Staph species?
 
penicillin - almost all resistantMethicillin, oxacillinVancomycin is alternative for resistant...
35
What infections are micrococcus associated with and what antimicrobials is it susceptible to?
 
Rarely infects humansSusceptible to most beta-lactams = penicillin


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