Vertical Transmission of Extended-Spectrum, Beta-Lactamase-Producing Enterobacteriaceae during Preterm Delivery: A Prospective Study.

Maternal carriage and vertical transmission of extended-spectrum, beta-lactamase-producing Enterobacteriaceae (ESBL-E), such as Escherichia coli, hamper the treatment of infections, resulting in high morbidity. E. coli is the most frequent cause of early-onset neonatal sepsis (EOS) in preterm infants, where ESBL-E are more frequently isolated. In this prospective, case-controlled study, maternal rectovaginal ESBL-E colonization and vertical transmission to preterm infants were assessed in 160 women with preterm premature rupture of membranes (PPROM; 57.4%) or preterm labor (42.6%); additional cultures were obtained from the placenta, amnion, and umbilical cord during preterm labor. Maternal and neonatal ESBL-E-carriage rates were 17.5% and 12.9%, respectively, and the vertical-transmission rate was 50%. Maternal ESBL-E colonization among women with PPROM was 21.3%, and in women with premature labor it was 12.6%. No correlation was observed between maternal ESBL-E-colonization and previous hospitalization or antibiotic administration during pregnancy. However, a correlation was found between placental inflammation and maternal ESBL-E colonization (p = 0.007). ESBL-E-colonized infants were delivered at an earlier gestational age and were more likely to have complications. Thus, the high ESBL-E carriage rate in women with threatened preterm labor, without obvious risk factors for carriage, and a high vertical transmission rate, combined with a correlation between placental inflammation and ESBL-E carriage, support maternal-neonatal ESBL-E-colonization surveillance and active measures to prevent ESBL-E-related EOS.