Occurrence and characteristics of blaOXA-181-carrying Klebsiella aerogenes from swine in China

Objectives

Klebsiella aerogenes is a largely understudied opportunistic pathogen that can cause sepsis and lead to high mortality rates. In this study, we reported the occurrence of carbapenem-resistant bla_OXA-181-carrying Klebsiella aerogenes from swine in China and elucidate their genomic characteristics.

Methods

A total of 126 samples, including 109 swine fecal swabs, 14 environmental samples, and three feed samples were collected from a pig farm in China. The samples were enriched with LB broth culture and then inoculated into MacConkey agar plates for bacterial isolation. After PCR detection of carbapenemases genes, the bla_OXA-181-carrying isolates were subjected to antimicrobial susceptibility testing, and whole-genome sequence analysis.

Results

Four Klebsiella aerogenes isolates carrying the bla_OXA-181 gene were obtained from swine faecal samples. All the 4 strains were belonged to ST438. The bla_OXA-181 genes were located in IncX3-ColKP3 hybrid plasmids with the core genetic structure of IS26-ΔIS3000-ΔISEcp1-bla_OXA-181-ΔlysR-ΔereA-ΔrepA-ISKpn19-tinR-qnrS1-ΔIS2-IS26, which suggests the potential for horizontal transfer and further dissemination of this resistance gene among Enterobacteriaceae and other sources.

Conclusions

This study represents the first instance of OXA-181-producing K. aerogenes being identified from swine faeces in China. It is crucial to maintain continuous monitoring and ongoing attention to the detection of K. aerogenes carrying bla_OXA-181 and other resistance genes in pigs.