BMC Public Health 2009, 9:437 http://www.biomedcentral.com/1471-2458/9/437 Table 4: Antimicrobial Sensitivity pattern of GBS isolated from pregnant women and neonates Antimicrobial agent GBS isolation (% of sensitivity) Vaginal Rectal Neonates Penicillin G Ampicillin Vancomycin Erythromycin Clindamycin Ciprofloxacin Cotrimoxazole Cefriaxone 98.1 100 100 87.0 83.3 94.4 90.7 87.0 90.6 100 100 81.3 84.3 93.8 84.4 84.4 100 100 100 81.3 87.5 100 87.5 93.8 Samples cultured from mothers and neonates showed that 37% of the pairs had positive GBS culture results, which is in keeping with other studies reporting transmis- sion rates ranging from 29% to 85% [17,18]. Of all the factors investigated, maternal colonisation was significantly higher in women of gestation age between 41 and 42 weeks compared to women of gestation age between 39 and 40 weeks, indicating an increase GBS car- riage with gestation age. The other maternal factors including social demographic factors were not signifi- cantly associated with GBS colonisation. In the present study GBS was isolated more frequently from women of age group 30-34 (32.1%) compared with women aged <20 years (15.4%), which is in contrast with reports from another study showing high isolation fre- quencies in women younger than 20 years [1]. These dif- ferences are difficult to explain but possibly underscore the fact that GBS colonisation might be influenced by multiple factors which may vary from one geographical location to another. This study revealed that women with no formal education (34.8%) were more likely to be colonised with GBS, a finding that is consistent with observations by Regan et al [19]. The association could be partly explained by the dif- ference in personal hygiene, which is more likely to be better among educated than the less educated women. GBS colonisation in the studied population was not asso- ciated with either HIV infection or CD4+ T cell count, probably due to the small sample of HIV infected preg- nant women among the studied population and the fact that only one woman had CD4 counts < 200 cells/μl. Of all possible factors for GBS colonisation in neonates that were investigated only prolonged duration of labour showed significant association, P < 0.001, probably due to prolonged exposure of the neonate in the birth canal. The strong association between prolonged labour and GBS colonisation calls for routine antibiotic prophylaxis in such women in order to decrease the chances of subse- quent neonatal infection. Other risk factors such as prolonged rupture of mem- brane, intrapartum fever, mode of delivery and low birth weight did not influence GBS colonisation in neonates. The lack of association with these factors can possibly be explained by the fact that the numbers of participants in this study with such risk factors were small (2%). We did not investigate the timing of caesarean section in relation to prelabor and post labour rupture of membrane versus spontaneous vaginal delivery, which could be viewed as one of the limitations of the study. However, the small number of women who delivered by caesarean section may not show any potential association. Notably all GBS isolated were sensitive to ampicillin and vancomycin, implying that these two antibiotics could be used for empiric prophylaxis. Most isolates (90% to 98%) were sensitive to ciprofloxacin and penicillin G and (80% to 90%) sensitive to clindamycin, erythromycin and ceftriaxone indicating the current value of these different antibiotics in the treatment and prophylaxis of GBS infec- tion in Dar es Salaam. Conclusion The high prevalence of GBS colonisation among pregnant women and neonates calls for screening of this bacterium in women attending antenatal care so that intrapartum antimicrobial prophylaxis can be offered to all women identified as carriers. Competing interests The authors declare that they have no competing interests. Authors' contributions AJ designed the study and supervised interviews, data col- lection and laboratory work. EFL and MIM assisted in design of the study and supervised laboratory work. FAM supervised clinical work. Finally, all authors participated in preparation of the manuscript, read and approved the final manuscript. Acknowledgements The authors would like to acknowledge the technical support provided by the members of the Departments of Microbiology and Immunology and Page 6 of 7 (page number not for citation purposes)