Study of Molecular Epidemiologic of Group B Streptococcus Colonization in Pregnant Women by PCR Method

Group B streptococcus(GBS)(Streptococcus agalactiae) is the leading cause of morbidity and mortality of the newborn infant and accounted as a factor leading septicemia after birth in mothers. Infections in infants are usually acquired by contact with the genital tract of the mother during labor and delivery. So a rapid screening test for group B streptococcus that could accurately identify pregnant women who are carrying the bacteria at the time of delivery would obviate the need for prenatal screening.The goal of this study was molecular epidemiology of group B beta Hemolytic Streptococcal(GBS) colonization in the vaginal flora of pregnant women. Samples were taken from mucus of anal and vaginal of 250 pregnant women during 35-37 week's ingestion by swap. Samples were tested by standard culture using Todd Hewitt Broth and Blood Agar and also by PCR using cfb gene. Culture identified 21(8.4%) women as carriage of GBS from 250 women but PCR assay could identify 24(9/6%) women. In comparison to culture results, sensitivity, NPV Specificity PPV of PCR Were(100%, 100% and 97%, 82%) respectively. The times that used for PCR assay and culture were 2h and 36h respectively. In conclusion, we found that group B streptococci can be detected rapidly and reliably by a PCR assay of combined vaginal and anal secretions from pregnant women at the time of delivery. Also this study shows that incidence of GBS is at high rate in Iranian pregnant woman, so we recommend screening of pregnant woman for detecting of GBS emphatically.