Genomic Insights Into Carbapenem-Resistant Klebsiella pneumoniae in Pediatric Bloodstream Infections in Zhejiang, China (2019-2024).

OBJECTIVES

Bloodstream infections (BSIs) caused by Klebsiella pneumoniae are associated with a significant risk of mortality. While the majority of existing research has concentrated on adult populations, there is a paucity of studies addressing pediatric cases. This study aims to elucidate the mechanisms underlying carbapenem resistance in K. pneumoniae strains responsible for bloodstream infections in children.

METHODS

A retrospective study was conducted at Children's Hospital, Zhejiang University School of Medicine, focusing on patients diagnosed with bloodstream infections due to carbapenem-resistant K. pneumoniae (CRKP). Antimicrobial susceptibility testing and whole-genome sequencing were subsequently performed.

RESULTS

In this study, all the CRKP-BSI strains were detected during the COVID-19 pandemic. The predominant mechanism of carbapenem resistance among the 10 CRKP-BSI strains was the production of class B metallo-beta-lactamases, with blaNDM-1 present in 50% of the strains, followed by blaNDM-5 (30%) and blaIMP-4 (20%). The ST25-KL2 lineage was the most prevalent strain, with all isolates originating from the neonatal intensive care unit (NICU). In strain 22WJ8105, hypervirulence-associated genes, including iucABC and iutA, were identified. Additionally, a strain of ST17-type K. pneumoniae harboring the blaNDM-5 gene was identified.

CONCLUSIONS

This study determined that the production of class B metalloenzymes is the primary mechanism of carbapenem resistance in pediatric bloodstream infections caused by CRKP. Importantly, the ST25-KL2 lineage emerged as the dominant clone, highlighting its potential for nosocomial transmission.