Genomic similarity of carbapenem-resistant Enterobacterales collected from mothers and their neonates.

OBJECTIVE

New Delhi metallo-β-lactamase is endemic in India and the gut may act as a reservoir of carbapenemase-producing Enterobacterales (CPE). Maternal gut colonisation with blaNDM-harbouring CPE increases the risk of neonatal gut colonisation. This study aimed to assess the vertical transmission of CPE from pregnant mothers (rectal) to neonates (rectal and blood).

METHODS

Rectal samples were collected and processed for the presence of CPE, followed by bacterial identification and antibiotic susceptibility. Mother-neonate pairs colonised with the same species underwent pulsed-field gel electrophoresis and whole-genome sequencing to examine genetic relatedness. Detection of blaNDM variants and their transmissibility was performed.

RESULTS

Of the pregnant mothers (n = 86) and sick neonates (n = 93) analysed, eight mother-neonate pairs harboured similar carbapenem-resistant species, predominantly Klebsiella pneumoniae, followed by Escherichia coli. Pulsed-field gel electrophoresis and whole-genome sequencing revealed that most isolates from mother-neonate pairs were distinct and distributed within diverse sequence types, including epidemic clones (ST11/15/147/405/410). blaNDM-1/5/7 were detected in CPE and predominantly associated with conjugative IncFII and IncFII(K) replicons. Genomic analysis supported one case of vertical transmission (ST147; blaNDM-1-positive K. pneumoniae) from mother to a neonate. Further investigation of exogenous sources is required to understand the acquisition of bacteria. No evidence of transmission of blaNDM-harbouring plasmids within mother-neonate pairs carrying distinct isolates was observed, indicating the independent acquisition of bacteria.

CONCLUSIONS

Although limited evidence of mother-to-neonate transmission was observed in this study, screening of the gut is necessary to understand CPE transmission in hospital settings and beyond. Targeted surveillance and infection-prevention policies are needed to curb CPE spread.