Evaluation of three selective enrichment media for detection of Group B Streptococcus in vaginal swabs

Journal: Kansenshogaku Zasshi. The Journal Of The Japanese Association For Infectious Diseases
Published:
Abstract

As the most common cause of neonatal sepsis, Lancefield Group B Streptococcus (GBS) must be diagnosed as early as possible in pregnant women is prevent neonatal infection. A selective enrichment broth medium has been widely recommended to optimally recover GBS from genital and anorectal samples. To establish a culture suitable for screening vaginal swab specimens, we compared subcultures of three selective enrichment media to direct culture on agar medium. Vaginal swab samples were inoculated directly onto 5% sheep blood agar and into New Granada medium (Eiken), Lim broth (Becton, Dickinson, and Company), and Todd Hewitt broth with gentamicin and nalidixic acid (Becton, Dickinson, and Company, Todd). Of the 288 specimens tested, GBS was recovered from 43 samples (14.9%) on direct agar media, with 82 (28.5%), positive on New Granada medium subculture, 67 (23.3%) on Lim broth subculture, and 61 (21.2%) on Todd, subculture. These results demonstrates that selective enrichment broth media provides more superior sensitivity than direct agar media for detection of GBS colonization in vaginal specimens, underscoring the usefulness of selective enrichment broth media in GBS screening for vaginal swabs in pregnant woman.

Authors
Rie Shibuya, Tomonari Yamashita, Shunsuke Shibuya, Miyuki Hasegawa, Akiko Kanayama, Fumiaki Ikeda, Intetsu Kobayashi, Akiyoshi Tsuji, Keizo Yamaguchi