Early neonatal acquisition of extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales in Madagascar and Cambodia: clonal and plasmid-level contributions of maternal gut carriage

Early neonatal infections caused by extended-spectrum-beta-lactamase-producing Enterobacterales (ESBL-PE) are prevalent in low- and middle-income countries, posing significant treatment challenges. This study investigated ESBL-PE colonization in 499 mother-neonate pairs from Madagascar and Cambodia, with stool samples collected at delivery and from neonates before day three. Using short- and long-read sequencing, identical isolates or plasmids were identified within each pair to assess neonatal acquisition from maternal source. Multinomial regression identified associated risk factors. Maternal gut carriage accounted for only 16.5% of neonatal ESBL-PE acquisition, suggesting that most cases originated from other sources. Primiparity and wet season were associated with an increased risk of acquisition from the mother, while cesarean delivery, neonatal resuscitation, and wet season were associated with acquisition from other sources. These findings challenge the paradigm that maternal carriage is the primary source of early neonatal ESBL-PE colonization, highlighting the need for further research into alternative sources to inform targeted interventions.