Objectives: To describe prevalence of phenotypic and genotypic macrolide-resistance among GBS isolates in pregnant women and explore the possibility of clonal spread of resistant GBS isolates in a multicultural population. Study design: Antimicrobial resistance patterns of 107 GBS isolates obtained from asymptomatic pregnant women were determined using E-tests. Macrolide resistance genes mef(A), erm(TR) and erm(B) were determined with PCR and a subset of 39 isolates, including the 8 isolates harbouring macrolide resistance genes, was subjected to RAPD analysis to detect clonal spreading. Results: Resistance to erythromycin and clindamycin was found in 8% and 7%, respectively. Macrolide resistance genes mef(A), erm(TR) and erm(B) were found in 1, 2 and 5 isolates, respectively; only five of these eight isolates exhibited both genotypic as well as phenotypic resistance. One genotype occured in 36% of the subset. Conclusions: Earlier reports on prevalence of phenotypic resistance were confirmed. Among the susceptible isolates one clonal type of GBS was clearly predominant; one of the resistant isolates shared its genotype. When such clonal types acquire resistance traits in the future, GBS disease may become harder to control.

Additional Metadata
Keywords Clonal spread, Group B streptococcus, Phenotypic and genotypic resistance
Persistent URL dx.doi.org/10.1016/j.ejogrb.2007.04.001, hdl.handle.net/1765/29600
Muller, A.F, Valkenburg-van den Berg, A.W, Kreft, D, Oostvogel, P.M, Sprij, A.J, & van Belkum, A.F. (2008). Low rate of carriage of macrolide-resistant group B streptococci in pregnant women in The Netherlands. European Journal of Obstetrics & Gynecology and Reproductive Biology, 137(1), 17–20. doi:10.1016/j.ejogrb.2007.04.001