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.

Objective: The proportion of neonatal early‐onset sepsis (EOS) by gram‐negative bacteria has increased. The authors examined bacterial distribution in the amniotic membrane cultures of women with peripartum fever (PPF) and related perinatal outcomes.Methods: This retrospective study covered the period 2011 to 2019. The primary outcomes were Enterobacteriaceae‐positive birth culture rates in women with PPF and the trend of ampicillin resistance. Maternal and neonatal outcomes were compared between women with group B Streptococcus (GBS) and Enterobacteriaceae‐positive isolates. Bacterial distribution was also compared according to rupture of membrane (ROM) duration.Results: Among 621 women with PPF, the positive birth culture rate was 52%. Increasing prevalences of ampicillin‐resistant Enterobacteriaceae (81%) were noted. Positive birth cultures were associated with maternal bacteremia (P = 0.017) and neonatal EOS (P = 0.003). Prolonged ROM ≥18 h was associated with increased risk for Enterobacteriaceae‐positive cultures, while intrapartum ampicillin and gentamicin were associated with lower risk. Enterobacteriaceae‐positive compared with GBS‐positive birth cultures were associated with adverse maternal and neonatal outcomes.Conclusion: Positive birth cultures were related to maternal bacteremia and neonatal sepsis. Adverse outcomes were more prevalent among women with Enterobacteriaceae‐positive versus GBS‐positive birth cultures. Prolonged ROM is a risk factor for Enterobacteriaceae‐positive birth cultures among women with PPF. Antibiotic prophylaxis treatment for prolonged ROM should be reconsidered.

Purpose: The aim of this study was to investigate the correlation between the thickness of meconium-stained amniotic fluid (MSAF) and maternal infectious morbidity. Methods: A retrospective study of 15,950 term singleton pregnancies at a tertiary hospital (2020–2024). Women were categorized into four groups based on the presence and thickness of MSAF: clear, light, intermediate, and thick. The co-primary outcomes were clinical chorioamnionitis and puerperal endometritis, defined as a composite maternal infectious morbidity. In women with intrapartum fever (IPF), chorioamniotic swabs were obtained and compared according MSAF thickness. Multivariate analysis identified predictors of a composite maternal infections and adverse neonatal outcomes. Results: Of the cohort, 13,745 had clear amniotic fluid, and 2,205 had MSAF (561 light, 1,426 intermediate, 218 thick). The incidence of maternal infections increased with MSAF thickness, with thick MSAF showing the highest rates of clinical chorioamnionitis (4.1%, p < 0.001) and endometritis (1.4%, p = 0.039). In IPF cases, thicker MSAF was associated with a higher prevalence of positive swab cultures, particularly of Enterobacteriaceae (61.9%). Group B Streptococcus (GBS) remained consistent across all MSAF groups. Multivariate analysis showed that MSAF levels were associated with increased maternal infectious morbidity (p < 0.001). Additional risk factors for maternal infections included nulliparity (p < 0.001), catheter balloon insertion (p = 0.004), prolonged ROM (p < 0.001), and cesarean delivery (p < 0.001). In contrast, only intermediate (p < 0.001) and thick MSAF (p < 0.001) correlated with adverse neonatal outcomes. Conclusion: Greater severity of MSAF is associated with increased maternal infectious morbidity, especially infections related to Enterobacteriaceae. Studies about preventive measures in cases of thick MSAF are warranted.