Cause:Streptococcus agalactiae, a group B strep
Pathophys:Vaginal colonization leads to newborn and maternal infections
(Jama 2008;299:2056) 0.6/1000 births; 2000/yr in US; 15-40% of pregnant women are colonized. Increasing incidence of serious (21% mortality) infections in nonpregnant adults as well as pregnant women, a minority of group B strep infections in the US now are in infants. Affects elderly and/or sick adults (Nejm 1993;328:1807, 1843), esp diabetics where causes bacteremias, cellulitis, pneumonia, osteomyelitis, arthritis, peritonitis, et al.
Sx:Floppy baby
Si:Newborn sepsis, and maternal chorioamnionitis, endometritis, and post-C/S wound infections
Lab:Bact:Gram-positive cocci in chains; usually ß-hemolytic; PCR assay 45-min test now possible at presentation in labor (Nejm 2000;343:175, 209)
Rx:Ampicillin iv (Nejm 2002;347:233, 240, 280; 2000;342:15; 1986;314:1665) intrapartum and to baby, in women with 35-37 wk prenatal positive vaginal/rectal cultures, AND fever, and/or premature labor (<37 wk), and/or prolonged (>12 h) ruptured membranes or various other risk-based or rx-all-carriers strategies, all of which tend to decr group B strep newborn sepsis but incr incidence of resistant E. colisepsis.