Evaluation of a new chromogenic agar medium for isolation and identification of Group B streptococci

Abstract

To evaluate a new chromogenic agar as a screening medium for the isolation of Group B streptococci from high vaginal swabs from pregnant women. The medium was evaluated with 195 high vaginal swabs referred for antenatal screening and compared with blood agar and Granada medium. The new chromogenic medium showed 100% sensitivity for the detection of Group B streptococci, and also showed a positive predictive value of 100%. Granada medium also showed excellent sensitivity and specificity and both media were superior to blood agar. The new chromogenic medium showed excellent performance for the detection of Group B streptococci from clinical samples. This is the first chromogenic medium described for the detection of Group B streptococci. The medium offers an effective and convenient alternative to conventional media, currently used in clinical laboratories.