Genital and intestinal carriage of group B streptococci during pregnancy.

To evaluate the relative importance of genital and gastrointestinal carriage of group B streptococci, repeated semiquantitative and qualitative cultures were obtained from 64 patients during pregnancy. Carriage was documented in 20% of the women at the first visit, in 41% of the women cumulatively, and at 24% of 295 visits. Group B streptococci were isolated from 20% of genital, 17% of rectal, and 17% of stool cultures. Concordance of carriage among these body sites was high (87%-93%) for cultures collected simultaneously. Counts of streptococci ranged between 10(2) and 10(7) colony-forming units per gram of dry stool (geometric mean, 2.3 x 10(5)) and varied widely among repeated samples from chronic carriers. The group B streptococci tended to appear, persist, and disappear simultaneously in genital, rectal, and stool cultures of individuals, although some women appeared to harbor the organism in the birth canal or lower bowel alone.