Page 1 of 1: Microbiology: STAPHYLOCOCCUS

cingulate_gyrus2006 · Credits: 22810 My Scrapbook

this is an AIIMS 2004 NOV question.
All of the following statements are true regarding staphylococci. Except.
a. A majority of infections caused by coagulase- negative Staphylococci are due to Staphylococcus epidermidis.
b. B- Lactamase production in staphylococci is under plasmid control.
c. Expression of methicillin resisance in staphylococcus aureus increases when it is incubated at 37 c on blood agar.
d. Methicillin resistance in staphylococcus aureus is independent of b-lactamase production.

drsmita_s · Credits: 18649 My Scrapbook

the answer lies in harri.
option a)
true : of all the coagulase negative staphylococccal infections, S. epidermidis is the most common human pathogen overall.

option b)
true: as a result of widespread dissemination of plasmids containing enzyme penicillinase , few strains of staph remain susceptible to penicillin.

option c)
false:
susceptibility studies are performed at reduced temp ( 30 to 35 deg C) for 24 hrs , to enhance the expression of resistance.

option d) true:
beta lactamase production is transmitted by a plasmid
whereas methicillin resistance is due to production of a novel penicillin binding protein synthesized by mecA gene.

aap · Credits: 2325 My Scrapbook

I agree. expression of resistance is enhanced at lower temperatures.

vivek_patel · Credits: 2551 My Scrapbook

3
Expression of methicillin resisance in staphylococcus aureus increases when it is incubated at 37 c on blood agar

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