Associations between maternal bacteremia during the peripartum period and early-onset neonatal sepsis: a retrospective cohort study

Introduction: Early-onset neonatal sepsis (EONS) significantly impacts neonatal morbidity and mortality, with maternal bacteremia during the peripartum period being a potential risk factor. This study aims to explore the association between peripartum maternal bacteremia and EONS. Methods: A retrospective cohort study at the Women's Wellness and Research Center in Doha, Qatar (2015–2019) compared women with and without bacteremia, based on blood cultures taken from up to seven days before to 48 h after delivery, examining the association with EONS. Results: Among the 536 maternal blood cultures analyzed, 102 (19.0%) were positive. The most prevalent organisms were Group B streptococcus (GBS) (39.2%), followed by Escherichia coli (14.7%) and anaerobes (10.8%). Neonates from bacteremic mothers had lower birth weights (2913 ± 86 g vs. 3140 ± 745 g; MD 227.63 g; 95% CI 61.72 − 393.55; p = 0.007), required more resuscitation (27.5% vs. 13.2%; OR 2.48; 95% CI 1.48 − 4.17; p < 0.001), and received antibiotics for ≥ 7 days more frequently (41.2% vs. 16.6%; OR 3.51; 95% CI 2.20 − 5.62; p < 0.001) compared to those from non-bacteremic mothers. Maternal Gram-positive (GP) organisms were more commonly isolated in term gestation (67.9%) compared to Gram-negative (GN) (22.2%) and anaerobic bacteremias (9.9%). During intrapartum, GP bacteremia was predominant (67.1%) vs. GN (21.4%) and Anaerobes (11.4%), with GN bacteremia being more common in postpartum samples. Culture-proven EONS occurred in 0.75% of the cohort, affecting 3.9% of infants from bacteremic mothers vs. none in controls (OR 2.34; 95% CI 1.27 − 4.31; p < 0.001). Culture-negative EONS appeared in 14.7% of infants from bacteremic mothers vs. 7.8% in controls (OR 2.02; 95% CI, 1.05 − 3.88; p = 0.03). Among 40 cases of maternal GBS bacteremia, culture-proven GBS EONS occurred in 3 neonates (7.5%), all from mothers with negative GBS screening, compared to none in the control group. A strong association was found between EONS and maternal bacteremia due to any organism (aOR 2.34; 95% CI, 1.24 − 4.41; p = 0.009), GP bacteremia (aOR 3.66; 95% CI, 1.82 − 7.34; p < 0.001), or GBS (aOR 5.74; 95% CI, 2.57 − 12.81; p < 0.001). Bacteremia due to GN and Anaerobic organisms were not associated with EONS. Chorioamnionitis and antepartum fever were independent predictors for EONS associated with significant bacterial isolates. Conclusion: This study underscores the significant impact of maternal GP bacteremia, particularly from GBS, on EONS. The strong association highlights the need for vigilant monitoring and interventions in pregnancies complicated by bacteremia to reduce adverse neonatal outcomes.