Point-of-care intrapartum molecular screening of group B Streptococcus reduced the incidence of early-onset disease cases and antibiotic use, according to research published in Obstetrics & Gynecology.

The real-time polymerase chain reaction (PCR) test, also known as a quantitative polymerase chain reaction (qPCR), works to amplify, as well as quantify a specific, or targeted DNA molecule. James Gathany/CDC

Najoua El Helali, PharmD, from the Service de Microbiologie Clinique at Groupe Hospitalier Paris Saint-Joseph, and her colleagues measured the rate of early-onset disease group B Streptococcus (GBS) in a single-center study analyzing antenatal culture screening for 4 years prior to implementation (2006-2009) of polymerase chain reaction (PCR) screening (2010-2015). There were 11,226 deliveries (11,818 live births) during the antenatal screening period and 18,835 deliveries (18,980 live births) during the PCR screening period. Overall, 4% of deliveries during the antenatal period and 0.1% of deliveries during the intrapartum period were not screened for GBS (P less than .001).

During 2006-2015, the rate of early-onset disease of GBS decreased to 0.21/1,000 cases from 1.01/1,000 cases (risk ratio, 0.25; 95% confidence interval, 0.14-0.43; P = .026), while the rate of probable early-onset disease GBS decreased to 0.73/1,000 cases from 2.8/1,000 cases (RR, 0.25; (95% CI, 0.14-0.43; P less than .001).

For patients with early-onset GBS, length of stay in hospital decreased by 64%, and antibiotic therapy decreased by 60%, but there was no significant difference in average length of stay or duration of antibiotic therapy during the study period. There was a reduction in annual delivery- and treatment-associated costs of early-onset disease GBS from $41,875 to $11,945, while the estimated extra cost of PCR screening to avoid one additional case of early-onset disease GBS was $5,819 and a cost increase of $49 per newborn.

“The additional PCR costs were offset in part by the reduction in early-onset GBS disease treatment costs,” the investigators said.

“A randomized, controlled multicenter study is probably needed to evaluate the cost-effectiveness of this prevention strategy and demonstrate a better efficacy in populations where poorly followed women are of unknown GBS status at presentation for delivery,” the researchers said. “In term newborns, however, using infection rate as an endpoint is problematic given the sample size needed.”

The researchers said their study was potentially limited by lack of a control group and population selection, and described mothers in their center as “mostly well-informed and well-monitored during their pregnancy.”

The authors reported no relevant conflicts of interest.

SOURCE: El Helali N et al. Obstet Gynecol. 2019. doi: 10.1097/AOG.0000000000003057.