Targeted screening for the detection of group B Streptococcus during the intrapartum period by real-time polymerase chain reaction

OBJECTIVES: To compare the intrapartum group B Streptococcus (GBS) detection rate and turnaround time in pregnant women using a polymerase chain reaction (PCR) assay versus a culture method, while also comparing GBS detection rates between a risk-based antibiotic-indicated group and the other high-risk group. METHODS: Pregnant women who presented with labor or ruptured membranes at ≥35 weeks of gestation and had any risk factors for GBS colonization were recruited. Paired vaginal-rectal swabs from 174 participants were evaluated by both real-time PCR and standard culture. RESULTS: Real-time PCR yielded a significantly higher GBS detection rate than the culture method (19.0% vs 5.7%, P < 0.01) and demonstrated significantly shorter turnaround time (4 hours vs 72 hours). No significant difference was found in detection rates between the risk-based antibiotic-indicated group and the other high-risk group (27.3% vs 18.5%, P = 0.19). CONCLUSION: Real-time PCR assay provides a higher and more rapid detection of GBS compared to culture methods. Our results suggest that other risk factors for GBS colonization (e.g., adolescent age, previous vaginal delivery, smoking during pregnancy) may be considered for IAP. CLINICAL TRIAL REGISTRATION: Thai Clinical Trials Registry (TCTR20210801003).