Rapid intrapartum PCR assay for group B streptococcus within a dutch risk-based strategy: diagnostic accuracy and optimization of antibiotic use in a single-centre cohort.

OBJECTIVE: To compare the diagnostic accuracy of a rapid intrapartum polymerase chain reaction (PCR) assay with standard intrapartum culture for detecting maternal group B streptococcus (GBS) carriage, and to explore potential effects on intrapartum antibiotic prophylaxis (IAP) within a Dutch risk-based strategy. BACKGROUND: GBS is a leading cause of early-onset neonatal sepsis. While many countries apply universal screening, the Netherlands follows a selective, risk-based prevention protocol with markedly lower use of IAP. Standard culture requires 24-48 h, limiting its value in urgent obstetric settings. Rapid intrapartum PCR testing offers results within 1 h and may improve timely decision-making. DESIGN: Retrospective diagnostic-accuracy cohort. SETTING: Secondary care teaching hospital in the Netherlands. POPULATION: Women who underwent both intrapartum PCR (Xpert Xpress GBS) and culture between 1 February and 30 September 2024 were identified retrospectively through electronic medical and microbiology records. Testing was performed in women with predefined clinical risk factors according to the local Dutch risk-based protocol. The same rectovaginal swab specimen was used for both rapid PCR analysis and standard culture testing. METHODS: Diagnostic accuracy of a rapid intrapartum PCR assay was calculated using culture as the reference standard, and expressed primarily as sensitivity and specificity with 95% confidence intervals (CI). PCR and culture results were processed through separate laboratory workflows. Exploratory analyses evaluated IAP administration and test performance across clinical risk factor groups. FINDINGS: A total of 177 women were analysed. The PCR assay showed sensitivity of 94.1% (95% CI 80.3-99.3) and specificity of 99.3% (95% CI 96.2-100.0). Of 33 PCR-positive women, 28 (85%) received IAP; non-treatment was due to rapid labour progression or informed refusal. Exploratory subgroup analyses demonstrated similar findings across prolonged rupture of membranes, preterm birth and other clinical risk factor groups. INTERPRETATION: Rapid intrapartum PCR testing demonstrated high diagnostic accuracy for GBS detection within a Dutch risk-based prevention protocol. Its integration may support more targeted use of IAP. Prospective multicentre trials are needed to establish clinical impact, cost-effectiveness and neonatal outcomes.