Comparison of a PCR assay to culture standard method for the screening of Group B Streptococcus in pregnant women Comparação de um ensaio de PCR com o método padrão de cultura para o rastreio de Streptococcus do grupo B em mulheres grávidas

Group B Streptococcus (GBS) is the most common cause of life-threatening infection in neonates. Guidelines from CDC recommends universal screening of pregnant women for rectovaginal GBS colonization. The objective of this study was to compare the performance of polymerase chain reaction (PCR) targeting the ATR gene in relation to culture using enrichment with selective broth medium (standard method) to identify the presence of GBS in pregnant women. Rectovaginal GBS samples from women at 36 weeks or more of pregnancy were obtained with a swab and analyzed by the two methods. A total of 89 samples were evaluated. Sensitivity of the PCR assay was 100%. ATR primers showed high analytic specificity for GBS identification in our assays. This PCR based test presented a higher prevalence of positive results (35.9% versus 22.5%) in comparison to standard method, providing a diagnostic tool for GBS detection, allowing more accurate and effective intrapartum antibiotic prophylaxis.