Comparison of Culture and PCR Methods for Diagnosis of Group B Streptococcus in Women

Group B Streptococcus (GBS), as a risk factor for newborns, is one of the most important causes of meningitis and septicaemia in newborns, intrauterine infections in women and colonization in the vaginal region in late gestation. We evaluate GBS prevalence and infection among pregnant women through culture and PCR methods, and then compare these methods. To this end, vaginal and urine swabs were separately collected from 246 women at the Women’s Hospital of Sari, Iran. Next, the samples were enriched in selective culture media Todd–Hewitt broth for 24 h at 37°C, recognized using blood agar media, and finally were amplified STREP gene by PCR technique. The indicated that the frequency of GBS in samples collected from urine and vaginal cultures and PCR method was positive. In addition, no significant relationship was found among the positive results of culture, maternal age, gestational age, a history of abortion and infection. With regard to the cultivation method as a standard technique, the sensitivity of PCR test was 100% and specificity was 96%. Moreover, it was found that the colonization rate of GBS in women was significant in Sari. Therefore, PCR is recommended as a reliable and rapid method for detection of GBS.