Prevalence of group B streptococcus in pregnant women attending a tertiary hospital in Ghana in 2001

Background: Group B streptococci cause major perinatal bacterial infections including chorioamnionitis and endometritis in women and severe systemic infections in the newborn. Infections are a major cause of newborn deaths in Ghana but the organisms causing these infections are usually not identified. Group B streptococci colonization during pregnancy, a prerequisite to potentially preventable early onset disease in the newborn is believed to be rare in pregnant women in Ghana. We undertook this pilot study to assess the veracity of this belief. Methods: General health education information on group B streptococcus was given to all women attending the Wednesday antenatal clinic at Korle Bu Teaching Hospital, Accra from April - June 2001. Anorectal and lower genital tract swab specimens were obtained from consecutive volunteers of 100 women in the third trimester of pregnancy. Specimens were inoculated onto selective Todd-Hewitt broth, incubated for 18 hours and sub-cultured onto sheep blood agar plate for group B streptococcus identification. Findings: Of the 2420 antenatal consultations at the Wednesday clinic during the study period, 32.2% (781/2420) of the attendants were in the third trimester of pregnancy. There were 21 isolates (12 anorectal, 5 genital and 2 at both sites) in 19 women; 19% of the pregnant women were carriers of group B streptococcus. Conclusion: The prevalence of group B streptococcus colonization in pregnant Ghanaian women is similar to that in other developed and developing countries. The rarity of isolates of group B streptococcus in Ghana may be due to inadequate microbiological methods.