Gram Positive Cocci
Which one of the following procedures is most likely to reduce the incidence of group B streptococcal disease in an infant?
|A||Identification of possible high-risk births|
|B||Intrapartum antibiotic treatment|
|C||Screening of pregnant females at the first office visit, usually during the first trimester|
|D||Screening of pregnant females in the last trimester|
a. The incidence of group B streptococcal (GBS) disease is 1 to 3 cases per 1000 births. Neonates acquire the disease during birth from mothers who harbor the organism.
b. Risk factors include prematurity, premature rupture of membranes, and group B streptococcal carriage. GBS can be reduced by intrapartum administration of penicillin.
c. While GBS is relatively more resistant to penicillin than group A streptococci, the great majority of GBS isolates are still penicillin-susceptible.
d. An aminoglycoside such as gentamicin may be added to GBS treatment regimens due to the relative reduced susceptibility of some strains.
Previously referred as enterococcal group D streptococci
a. Normal flora of lower intestinal tract
b. Non motile, non capsulated, gram + cocci in pairs, short chains
c. , or non- hemolytic on sheep blood agar
d. MacConkey’s agar: tiny magenta colored colonies (LF)
e. Grow in presence of 6.5% NaCl, pH 9.6, at 10C & 45°C
f. Grow in presence of 40% bile, hydrolyze aesculin
g. PYRase test +
h. Survive 60c for 30 min
i. Resistant to penicillin (altered PBP’s) and aminoglycosides (decreased uptake)
i. E. faecalis: most common; E. faecium , E. durans
ii. Most common infections-UTI, wound infection, endocarditis, Peritonitis, Septicemia