Colonization with Group B streptococci in pregnancy and outcome of infected neonates in Trinidad

Background: The present study took place at the antenatal clinics of the San Fernando General Hospital located in the south and the Mount Hope Maternity Hospital located in the north-west of the West Indies, respectively. Participants were from the lower socioeconomic group that included representatives from the two major ethnic groups, East Indians and people of African descent. Methods: We prospectively analyzed data on 201 third trimester pregnant women. All had singleton pregnancies. Culture specimens for group B streptococcus (GBS) were obtained from the rectum and anterior one-third of the vagina, and inoculated directly onto selective media. Blood culture from neonates (born to GBS carrier mothers) suspected of sepsis was also screened for GBS. Group B streptococci were identified via colonial morphology, beta-hemolysis, and biochemical reactions, and confirmed via latex agglutination tests. Antimicrobial susceptibility testing was done. Data were computerized and statistically analyzed using the Statistical Package for the Social Sciences. Associations between age, ethnicity and gravidity were evaluated using Pearson's chi(2) test. Results: The prevalence of vaginal and rectal GBS colonization was 32.9%. Group B streptococci were isolated more frequently from women >24 years (36.6%) than those younger than 24 years (26.9%), and more so, from women of East Indian descent (37.3%) than women of African descent (27.2%). Colonization rates were significantly greater among multigravid women than primigravid women (P < 0.001). Of the 13 infants admitted after delivery, five were confirmed cases of sepsis. Group B streptococci were isolated from the blood of three of these infants, and one case was fatal. Although all GBS were fully sensitive to ampicillin and amoxicillin-clavulanic acid, 94% were resistant to tetracycline and approximately 88% to co-trimoxazole. Only approximately 8% were resistant to erythromycin. Conclusion: The carriage rate of GBS among pregnant women in the present and a previous study, remain high. Attempts to establish and implement a program aimed at GBS disease prevention have met with repeated failure. Data on the prevalence of GBS neonatal disease, preventative measures and outcome of infected infants are greatly needed.