Intrapartum Group B streptococcus detection by rapid polymerase chain reaction assay for the prevention of neonatal sepsis

Abstract

Group B streptococcus (GBS) is a leading cause of infectious neonatal morbidity and mortality. Timely and accurate identification of colonized mothers is imperative so that antibioprophylaxis can be implemented during labour to reduce the risk of neonatal sepsis. We planned our study to analyse the diagnostic accuracy of an intrapartum PCR assay to identify GBS-colonized women and to allow the implementation of correct (i.e. at least 4 h) intrapartum antibiotic prophylaxis based on the PCR results. We included 695 women in labour who were tested for rectovaginal GBS carriage by culture and PCR. Women were also screened at 35-37 weeks of gestation. Intrapartum GBS colonization was 19.3%. Assay sensitivity was 81.0% for antenatal culture and 85.0% for intrapartum PCR; p 0.72. GBS colonization (n = 107) was known at least 4 h before delivery in 68 (64%) and 73 (68%) women based on antenatal culture and intrapartum PCR, respectively. Among 43 women delivering preterm, correct status was known at least 4 h before delivery in 10 (23%) and 32 (74%) women according to antenatal culture and intrapartum PCR, respectively. These results support the concept that GBS screening can be performed routinely during labour in a clinical setting. The intrapartum approach is at least as accurate as the antenatal screening, with the additional advantage of identifying women delivering preterm or not followed during pregnancy.

Molecular-based Screening for Perinatal Group B Streptococcal Infection: Implications for Prevention and Therapy

“…have predictable antimicrobial susceptibilities and their detection is frequently clinically meaningful [35]. A PCR-based POC test, such as Xpert Ò GBS, can be performed by non-laboratory personnel (i.e., midwives) in the labor suites [36]. It has been shown to be at least as accurate as the antenatal culture-based screening with the advantage of identifying those women who are really carrying GBS during labor and allowing for targeted IAP.…”

“…It has been shown to be at least as accurate as the antenatal culture-based screening with the advantage of identifying those women who are really carrying GBS during labor and allowing for targeted IAP. Moreover, it allows for screening pregnant women whose babies are at higher risk for neonatal sepsis, such as those delivering preterm or not followed during pregnancy [36]. However, because of the reimbursement system used in most countries (diagnostic related groups), hospitals are not inclined to add laboratory examinations to in-hospital treatments, and it is difficult to convince hospital administrators to invest in strategies to spare antibiotic use if their application is more costly than the price of the antibiotic itself.…”

Intrapartum GBS screening and antibiotic prophylaxis: a European consensus conference

“…Rapid real-time PCR assays for GBS detection have been further developed and their performances have been evaluated these last years as summed up in Table 2. When compared to enriched GBS cultures, sensitivity and specificity for PCR tests range from 62.5%-100% and 84.6-100% while PPV and NPV range from 65-100% and 92.3-100% [80,82,[84][85][86][103][104][105][106][107][108][109][110][111]. Today, real-time PCRbased tests (NAAT) can equal or surpass the sensitivity of antenatal culture at 35-37 weeks' gestation and compare favorably with reference to bacterial culture performed at presentation for delivery taken as gold standard for the detection of GBS colonization [80,82,101,102,112].…”

“…However the expected predictive values were too optimistic. In studies evaluating antenatal culture to predict intrapartum status for genital colonization with GBS, reported sensitivities range from 51% to 87%, specificities from 93.7% to 97.1%, positive and negative predictive values from 60.6% to 87% and from 88% to 96% [77,[79][80][81][82][83][84][85][86][87].…”

Evaluation of the Cepheid Xpert GBS Assay for Rapid Detection of Group B Streptococci in Amniotic Fluids from Pregnant Women with Premature Rupture of Membranes

“…A nucleic acid amplification test (NAAT) may be able to identify women who are positive at the time of delivery. The Xpert GBS (Cepheid) has shown to be an accurate and easy-to-use PCR for the detection of GBS DNA from vaginal or rectal specimens (8,9). With Xpert GBS intrapartum screening, significant decreases in neonatal infections and the length of stay (LOS) were demonstrated (47% fewer hospitalization days in neonatology/90% fewer days in the intensive care unit [ICU]) (10).…”