Prevalence of group B streptococcal colonization in pregnant third trimester women in Trinidad.

A study of colonization by group B streptococcus was conducted in 204 pregnant women in their third trimester. Positive cultures were obtained from vaginal and rectal swabs in 64 (31.4%) of these women. No significant differences in colonization rates were noted on the basis of ethnicity (race) and gravidity. However, there was a significant difference in the rate of colonization of vagina and rectum. Fifty-two (25.5%) women had positive isolates from vaginal swabs compared with 26 (12.7%) women with positive rectal isolates (P < 0.05). There was a significant trend of increasing prevalence with increasing age. Colonization was not significantly greater in multigravid than in primigravid women. There was no significant difference between colonization in Negro (black) women and colonization in East Indian women.