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.

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doi.org/10.1016/j.ejogrb.2007.04.001, hdl.handle.net/1765/29600
European Journal of Obstetrics & Gynecology and Reproductive Biology
Erasmus MC: University Medical Center Rotterdam

Muller, A.E, 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