A public health concern: emergence of carbapenem-resistant Klebsiella pneumoniae in a public transportation environment.

OBJECTIVES: This study was designed to understand the prevalence of antibiotic-resistant bacteria in the Beijing subway environment and the potential transmission of carbapenem-resistant Enterobacteriaceae in a public transportation environment. METHODS: Carbapenem-resistant isolates were selected on brain heart infusion agar supplemented with meropenem (0.5 mg/L) and antimicrobial susceptibility testing was conducted using the broth microdilution method. WGS analyses were conducted for 11 Klebsiella pneumoniae isolates to identify resistance genes. The genetic relationships among the isolates were evaluated by MLST and PFGE. RESULTS: We identified 11 carbapenem-resistant K. pneumoniae isolates from the Beijing subway environment. WGS revealed three STs among the 11 isolates, with 9 isolates classified as ST726 and containing a blaNDM-5-carrying IncX3 plasmid. The genetic environment of blaNDM-5 was very similar to that observed in other blaNDM-5-containing clinical isolates. CONCLUSIONS: The presence of carbapenem-resistant Enterobacteriaceae in a public transportation environment is concerning and indicates that regular antimicrobial resistance surveillance is urgent and necessary.