Occurrence and characteristics of bla-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-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-carrying isolates were subjected to antimicrobial susceptibility testing, and whole-genome sequence analysis.

RESULTS

Four Klebsiella aerogenes isolates carrying the bla gene were obtained from swine faecal samples. All the 4 strains were belonged to ST438. The bla genes were located in IncX3-ColKP3 hybrid plasmids with the core genetic structure of IS26-ΔIS3000-ΔISEcp1-bla-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 and other resistance genes in pigs.