Abstract
Background : Streptococcus agalactiae (GBS) is a causative pathogen of meningitis and sepsis in neonates. We utilized a realtime PCR method for rapid detection of GBS in prenatal vaginal specimens.
Materials and Methods : Vaginal swab samples (n=500) were collected from pregnant women aged 15 to 45 yr at 37 gestation weeks in Juntendo University Shizuoka hospital between September 2008 and September 2009. Samples were immediately analyzed by real-time PCR in parallel with routine bacterial cultivation. The next day, capsular type of GBS colony grown on the blood agar plate was identified by real-time PCR.
Results : Sensitivity of PCR for 3 reference GBS stains was 10 CFU/well at 32 threshold cycle (Ct). Time required for real-time PCR analysis was about 1.5 hours. Of all the tested samples, 20.2% were PCR positive. GBS positive rates by age group were 23.4%, 18.0%, 13.3%, and 11.1% in the 30s, 20s, 40s and 10s, respectively. Predominant capsular type of GBS was serotype Ib (19.7%), followed by serotypes V (18.2%), VI (16.7%), Ia (12.1%), III (12.1%), VIII (9.1%), and II (4.5%). The parenteral antibiotic piperacillin was administered for the GBS-positive pregnant women and resulted in no GBS infection in newborns.
Conclusions : We demonstrated that the GBS-specific real-time PCR assay was a sensitive and rapid tool for detection in pregnant GBS carriers compared to routine culture test, which may lead to timely use of prophylactic intrapartum antibiotics.
