Intrapartum PCR assay is a fast and efficient screening method for Group B Streptococcus detection in pregnancy

The aim of the study is to verify the usefulness of a real-time polymerase chain reaction versus the culture for ante- and intrapartum group B Streptococcus maternal colonization (GBS) and prevalence of discordance during the period between an antepartum screening and delivery.

The study involved 106 pregnant women aged 18 to 39 years. Rectovaginal samples were collected according to CDC guidelines at 35-37 weeks of gestation as well as in the first stage of labour, during physical examination and were analyzed using two independent diagnostic methods: microbiological culture with standard culture and polymerase chain reaction with real-time assay.

The discordance between antenatal and intrapartum GBS prevalence has been demonstrated as well as differences associated with diagnostic strategies, culture and PCR.

Intrapartum detection of GBS colonization using culture or Real-Time PCR assay as well, regardless of antenatal screening test for GBS, is very useful in identifying women who require implementation or withdrawal from prophylactic intrapartum antibiotic therapy. Real-Time PCR is a quick efficient method for GBS screening in pregnant women, which can be even applied during labor due to its short time of analyzing and high sensitivity and specificity. The above fact may indicate the need to perform the GBS test in the intrapartum period in all pregnant GBS negative women using PCR assay as a more adequate diagnostic method as the procedure could reduce the risk of a neonatal GBS infection subsequently to a prophylactic antibiotic therapy in women with an intrapartum positive GBS.