Evaluation of four chromogenic media for the isolation of Group B Streptococcus from vaginal specimens in pregnant women

Pathology. 2015 Oct;47(6):580-2. doi: 10.1097/PAT.0000000000000299.


Direct culture onto four commercial chromogenic media, selective for the isolation of Group B Streptococcus (GBS), were compared with the conventional pre-enrichment Centers for Disease Control and Prevention (CDC) method for the ability to isolate GBS from 242 pregnant women's self-collected vaginal/perineal swabs. The sensitivities and specificities for direct culture on to chromogenic agar were 92% and 100% for StrepBSelect (Bio-Rad Laboratories), 96% and 100% for Brilliance GBS (Thermo-Fisher Scientific), 94% and 100% for CHROMagar StrepB (CHROMagar, Dutec Diagnostics), 86% and 100% for ChromID Strepto B (bioMerieux). CDC recommended broth pre-enrichment then culture on blood containing selective agar had a sensitivity and specificity of 90.0% and 100% respectively. The chromogenic agar tested produced comparable results to the pre-enrichment CDC method.

MeSH terms

  • Bacteriological Techniques / methods*
  • Chromogenic Compounds*
  • Culture Media*
  • Female
  • Humans
  • Pregnancy
  • Pregnancy Complications, Infectious / diagnosis*
  • Sensitivity and Specificity
  • Streptococcal Infections / diagnosis*
  • Streptococcus agalactiae
  • Vaginal Smears


  • Chromogenic Compounds
  • Culture Media