Vaginal colonization and resistance profile of Group B Streptococcus among pregnant women in Yaoundé Gynecology-Obstetric and Pediatric Hospital

Abstract Setting: In order to obtain reliable data on vaginal carriage of Streptococcus agalactiae in pregnant women in Yaounde and to formulate a prevention program of neonatal Group B Streptococcus (GBS) disease, we carried out a prospective cross sectional study for 6 months  March 1 st to  August 30 th ;  2008 . The general objective of the study was to evaluate the prevalence of vaginal carriage and the resistance profile of GBS in pregnant women. Methodology: The study involved 142 pregnant women presenting for antenatal care in Yaounde Gynecology-Obstetric and Pediatric Hospital (YGOPH). Participants were interviewed using a standard structure questionnaire to gather demographic data and other relevant informations such as maternal age, gestational age, previous gyneco-obstetric history, parity and administration of antibiotics. Low vaginal swabs were collected and cultured on specific media. A presumptive identification of isolates was made using standard bacteriological methods. These included colonial morphology, haemolysis, catalase test, Gram staining. Confirmative identification of Group B Streptococcus was done using latex agglutination test with specific antiserum using the slidex Strepto Plus. Antimicrobial sensitivity testing was performed by the disk-diffusion (Kirby-Bauer) method. The sensitivity of the following reference strain American Type Culture Collection (ATCC): Staphylococcus aureus ATCC 25923 was tested. The results were only validated when the diameters of the inhibitions zones of the reference strain were in accordance.  Results : Among the 142 pregnant women presenting for antenatal care in Yaounde Gynecology-Obstetric and Pediatric Hospital (YGOPH), GBS colonization was confirmed  in 11 (7.7%). The rate of carriage was 3.8% in the first trimester, 7% in the second trimester and 11.1% in the third trimester. The predominant germ was Candida albicans with a frequency of 45.2% among the germs found in monomicrobial culture and Gardnerella vaginalis (77.8%) among the germs in polymicrobial culture, followed by Candida spp (11.8%), Streptococcus agalactiae (8.6%) and Escherichia coli (4.3%) The result of antimicrobial sensitivity testing showed that all the GBS strains were sensitive to major antibiotics drugs tested. The highest rates of resistance were found with gentamycin (100%) and Cefuroxim (81.8%). Conclusion: The vaginal carriage of GBS among pregnant women is still high. Data on the prevalence of GBS neonatal disease, preventive measures and outcome of infected infants are greatly needed in our country to allow the most appropriate preventive strategy to be selected. Thus, well-planned, prospective studies will be necessary to fully appreciate the magnitude of the problem of GBS in our hospitals Key words: Group B Streptococcus, vaginal colonization, pregnant women, Resistance profile, Yaounde.