Intrapartum Test for Detection of Group B Streptococcus Colonization During Labor

Maternal colonization with group B streptococcus (GBS) leading to neonatal sepsis remains a predominant cause of neonatal morbidity and mortality in the world. Many countries have adopted screening strategies, such as the antepartum GBS screening culture at 35 to 37 weeks of pregnancy (antepartum culture), to identify women who need intrapartum antibiotic prophylaxis (IAP) in order to avoid the GBS peripartum transmission to the fetus. This prophylaxis has reduced, but not eliminated, the incidence ofGBS early-onset disease in neonates. In order to improve GBS-colonized pregnancymanagement during delivery, the European consensus conference recommended IAP based on a GBS intrapartum test. The development of rapid molecular tests, based on nucleic acid amplification testing (NAAT), has furthered the possibility of intrapartum GBS testing. In the current study, the researchers performed a single-center cohort study, enrolling 313 women at beginning of labor, with unknown GBS status or with antepartum GBS screening culture. Avaginal-rectal specimen was collected from each woman for GBS detection by real-time polymerase chain reaction (PCR). The results of intrapartum test and antepartum GBS screening culture were compared. All pregnant women enrolled in the study attended the obstetrics and gynecology outpatient clinic of the Perugia University, Italy, between 2014 and 2016. In 15.1% of the cases, the antepartum culture was not concordant with the intrapartum GBS test. However, when selecting only women who underwent antepartum culture and intrapartum test at the same time, the percentage of concordance was 96.6%. Based on intrapartum test results, 74.9% of the total number of IAP was administered uselessly, whereas 1.9% of women did not receive IAP, although they were positive on the intrapartum test. The intrapartum test was found not to be cost-effective when compared with antepartum culture, but it would be cost-effective at a lower cost of (sic)16. The researchers concluded that the clinical introduction of intrapartum test could be a valuable mean for identification of GBS colonization during labor, allowing an appropriate management of mothers and neonates with consequent benefit for their health.