Group B beta-hemolytic streptococci in an intramural neonatal population.

An intramural population of 2480 neonates (88.7% of total births at the Grace Maternity Hospital, Halifax, Canada) was studied by rectal swabs collected within one hour after birth. Group B streptococci were recovered from 54 (21.7/1000 livebirths). Of these, 12(4.8/1000 livebirths) became symptomatic; all were term infants and none was born after prolonged membrane rupture. Two infants with pneumonia (0.8/1000) had severe life threatening illness; one was infected with group B streptococcus, serotype III, the other with both serotypes Ia and II. Serotyping of isolates showed equal distribution of types Ia, Ib, II and III but the symptomatic group showed a predominance of serotype III.