Bacterial DNA detection in very preterm infants assessed for risk of early onset sepsis

The aim of this study is to evaluate the diagnostic ability of multiplex real-time polymerase chain reaction (PCR) in very preterm infants assessed for risk of early onset neonatal sepsis (EOS).

Prospective observational cohort study. Blood samples of preterm neonates ≤32 weeks of gestation were evaluated by commercial multiplex real-time PCR within 2 h after delivery. The definition of EOS was based on positive blood culture and clinical signs of infection or negative blood culture, clinical signs of infection and abnormal neonatal blood count and serum biomarkers.

Among 82 subjects analyzed in the study, 15 had clinical or confirmed EOS. PCR was positive in four of these infants (including the only one with a positive blood culture), as well as in 15 of the 67 infants without sepsis (sensitivity 27%, specificity 78%). Out of 19 PCR positive subjects, Escherichia coli was detected in 12 infants (63%). Statistically significant association was found between vaginal E. coli colonization of the mother and E. coli PCR positivity of the neonate (p=0.001). No relationship was found between neonatal E. coli swab results and assessment findings of bacterial DNA in neonatal blood stream.

Multiplex real-time PCR had insufficient diagnostic capability for EOS in high risk very preterm infants. The study revealed no significant association between PCR results and the diagnosis of clinical EOS. Correlation between maternal vaginal swab results and positive PCR in the newborn needs further investigation to fully understand the role of bacterial DNA analysis in preterm infants.