Bile medium for rapid presumptive identification of group B streptococci

A bile medium was developed for rapid presumptive identification of beta hemolytic group B streptococci. Of 131 clinical isolates of group B streptococci, 125 (95.4%) yielded positive reaction within 6 h incubation. No false positive reaction was found in 134 clinical isolates of groups A, C, F, and G beta-hemolytic streptococci. The sensitivities of the bile medium, rapid hippurate hydrolysis and modified LAL-1 medium were 95.4, 98.5 and 93.1%, respectively. All three media showed 100% specificity. Therefore, the bile medium provides as an additional medium for rapid presumptive identification of group B streptococci.