Evaluation of a new chromogenic medium (StrepB select) for detection of group B Streptococcus from vaginal-rectal specimens.

We compared StrepB Select medium (Select) after enrichment with conventional culture for the detection of Group B Streptococcus (GBS). Postenrichment sensitivities of Select and conventional culture were 98.8% and 92.2%, respectively (P<0.05). Select was superior for detection of GBS from vaginal-rectal specimens. Growth of non-GBS colonies required additional work to exclude the presence of GBS, especially after 48 h of incubation. Incubation of Select beyond 24 h did not significantly increase the yield of GBS.