Accuracy of prenatal culture in predicting intrapartum group B streptococcus colonization status

Abstract

Objective: To evaluate the positive predictive value (PPV) of group B Streptococcus (GBS) cultures at 35–37 weeks of gestation relative to GBS colonization status at delivery.

Methods: Rectovaginal swabs from 221 women at labor in four Lisbon hospitals were collected for GBS screening according to the CDC guidelines.

Results: The PPV was 24.4%. IAP was administered to 100% of prenatally GBS positive women. There was no case of early onset GBS disease (EOD).

Conclusions: Poor accuracy of prenatal cultures in identifying true candidates for IAP highlights the need for Portuguese clinical and laboratory guidelines to prevent EOD and antibiotic overtreatment of pregnant women.

• Early onset disease
• intrapartum antibiotic prophylaxis
• intrapartum screening
• Streptococcus agalactiae

Acknowledgements

The authors thank Albertina Louro (National Institute of Health); Conceição Telhado, Mariana Loureiro, Glória Carvalhosa, Mafalda Lucas, Maria João Santos, Maria do Céu Ramalho, Rosa Portela, Luís Mós, Anaílde Araújo, and Cristina Castel Branco (CUF Descobertas Hospital); Ana Lima, and Patrícia Silva (Maternity Alfredo da Costa); Graciete Novais, Elsa Guerreiro, Cecília Artilheiro, Pedro Mendes, António Fatia, and Lilita Miranda (Fernando Fonseca Hospital) for collecting/processing clinical samples.