eThe Xpert GBS real-time PCR assay was applied to gastric fluid samples from 143 newborns, and it detected group B streptococcus (GBS) within 1 h for 16 (11.2%) cases, while microscopic examination detected only 2 cases. The sensitivity and specificity of the Xpert GBS were 80% and 100%, respectively, with regard to 20 cases of GBS colonization or infection. Concordance of Xpert GBS results versus culture was 92.3%. This test detects in a timely manner newborns at risk for invasive GBS disease.
Early-onset group B streptococcus (GBS) neonatal disease is a serious and frequent complication of birth in developed countries. GBS causes more than one-third of the materno-fetal infections (MFI) of term infants, followed by Escherichia coli and other Streptococcus spp., as well as species now classified in the Enterococcus genus (1). GBS colonizes the maternal genitourinary tract (at reported frequencies from 4 to 36%) during pregnancy in Europe and the United States (2) and may cause an ascending infection after the onset of labor or the preterm rupture of membranes. Neonates may become colonized (in 40 to 70% of the cases [3]) during passage through the birth canal at the time of delivery. Two strategies have significantly reduced the rate of early neonatal GBS colonization and infection (4): (i) late antenatal GBS screening of pregnant women and (ii) intrapartum chemoprophylaxis for colonized women to reduce vertical transmission of GBS. Despite international guidelines, the worldwide incidence rate of GBS neonatal diseases is still 0.23 to 1.22‰ of births (5, 6).Because early detection of infected newborns is clinically difficult and the newborn's health can worsen rapidly, GBS detection for newborns is one of the emergencies in clinical microbiology. Gastric fluid is the usual relevant specimen for GBS detection (7). Its microscopic examination is so far the only bacteriological finding rapidly available for clinicians who suspect an early MFI. GBS microbiological diagnosis is delayed, since it is based on an 18-h culture. Since microscopic examination has a low sensitivity (27.5%) (8), a rapid method of GBS detection that is reasonably sensitive and specific would be valuable in stratifying the risk of MFI among neonates.The Xpert GBS assay (Cepheid) is a marketed real-time PCR for screening maternal carriage by detecting GBS DNA in vaginal or rectal specimens. Recently, two studies have shown its utility when it is performed on vaginal swabs during intrapartum instead of antenatal screening, at 35 to 37 weeks of gestation (9), and on amniotic fluids collected from pregnant women with premature rupture of membranes (10). Our study aimed to evaluate the test's performance when applied to gastric fluid specimens collected from newborns. Our aim was to shorten the time to detect GBScolonized infants and thus help in the diagnosis of invasive GBS materno-fetal infections.We conducted a prospective study at Lariboisière University Hospital (Paris, France), where 2,500 deliveries are processed per year in an IIA matern...