A RAPD-PCR genotyping assay which correlates with serotypes of group B streptococci

Abstract

Aims: The purpose of this study was to determine if DNA polymorphisms generated by RAPD-PCR could be used to characterize Group B streptococci (GBS) for epidemiological purposes. Methods and Results: 30 unrelated, previously serotyped strains were analysed by RAPD-PCR using two 10-mer primers (5' TGCGAGAGTC 3' and 5' AGAGGGCACA 3'). Both primers generated DNA electropherotype patterns which, on analysis, clustered the isolates within their respective serotypes. A blind test of a further 3 field isolates also defined these strains within their subsequently determined serotypes. The detection of DNA polymorphisms between isolates within a serotype confirmed previous reports of the heterogenous nature of individual GBS serotypes. Conclusions: The RAPD-PCR is a potentially useful assay for the rapid characterization of neonatal infections associated with group B streptococci. The method appears to be more discriminatory than conventional serological assays. Significance and Impact of the Study: The RAPD-PCR assay is faster, more convenient and easier to perform than alternative DNA analytical procedures such as Pulsfield Gel Electrophoresis. We were able to reproduce the same results following re-testing of all isolates some 12 months later which suggests that the assay may be robust enough for use in routine epidemiological investigations.