[Comparative study of three culture media for detecting group B Streptococcus colonization in pregnant women].

Objective: To compare the efficacy of three culture media to detect vaginal and rectal colonization by group B streptococci (GBS) in pregnant women.

Methods: We processed 1334 samples from 861 pregnant women: in 388 patients only vaginal swab was cultured (Group A) and in 473 vaginal and rectal swabs were cultured (Group B). Samples were inoculated on blood agar with colistin-nalidixic acid (BA-CNA), on plates with Granada medium, and on Todd-Hewitt broth (THB) with amikacin followed by subculture in BA-CNA.