Rapid group B streptococci screening using a real-time polymerase chain reaction assay

Area of Science:

• Microbiology
• Clinical Diagnostics
• Molecular Biology

Background:

• Group B Streptococcus (GBS) is a leading cause of invasive bacterial infections in newborns.
• Accurate and rapid detection of GBS is crucial for timely antibiotic prophylaxis during pregnancy and labor.
• Current GBS detection methods, primarily culture-based, can be time-consuming.

Purpose of the Study:

• To evaluate the clinical performance of a real-time polymerase chain reaction (PCR) assay for GBS detection.
• To assess the assay's utility in antepartum and intrapartum pregnant women.
• To compare the PCR assay's performance against standard culture methods and a predicate nucleic acid amplification test.

Main Methods:

• A multicenter clinical study involving pregnant women (antepartum and intrapartum) was conducted.
• Vaginal/rectal swabs were analyzed using a qualitative, automated, real-time PCR assay with results in approximately 75 minutes.
• PCR results were compared to standard culture methods and a predicate nucleic acid amplification test.

Main Results:

• Valid PCR assay results were obtained on the first attempt for 93.0% of eligible women.
• The PCR assay demonstrated high performance characteristics compared to culture: sensitivity 91.1%, specificity 96.0%, positive predictive value 87.8%, negative predictive value 97.1%, and accuracy 94.8%.
• The PCR assay's performance exceeded that of the predicate nucleic acid amplification test.

Conclusions:

• The real-time PCR assay exhibits performance characteristics superior to the CDC-recommended thresholds when compared to culture.
• The assay is robust and suitable for point-of-care testing in intrapartum settings.
• This rapid PCR test offers a valuable alternative for GBS detection in pregnant women.