Preliminary evaluation of Hitchens–Pike–Todd–Hewitt medium (HPTH) for detection of group B streptococci in pregnant women

Abstract

We aimed to compare Hitchens-Pike-Todd-Hewitt (HPTH) enrichment broth, Todd-Hewitt broth, and direct culture onto blood sheep agar containing selective antimicrobial (ABA) in screening Group B Streptococci (GBS) carriage in pregnant women. From April to June 2007, duplicate lower vaginal and duplicate anorectal specimens of 102 pregnant women at 35 weeks of gestation or more, who were assisted at Santa Casa de Misericórdia Hospital, Maringá, Paraná, Brazil, were screened by GBS using HPTH, Todd-Hewitt broth, and ABA. Twenty-five (24.5%) pregnant women had one or more positive culture for GBS in those media. The positive rate for each medium was 21.6% (22/102) in the HPTH, 12.8% (13/102) in ABA, and 11.8% (12/102) in Todd-Hewitt broth. HPTH seems to be a high satisfactory medium for screening GBS in vaginal and anorectal samples in pregnant women and additional studies would be interesting in a larger number of pregnant women and in different laboratories.