The occurrence and genomic characteristics of the blaIMI-1 carbapenemase-producing Enterobacter cloacae complex retrieved from natural water sources in central Thailand

Aim: Carbapenem resistance among Enterobacteriaceae is a serious threat to humans worldwide. This study aims to evaluate the phenotypic and genotypic characterization of carbapenemase-producing Enterobacter cloacae complex (ECC) retrieved from water sources in the central part of Thailand. Methods and results: Samples were collected from water bodies surrounding farms and communities in central Thailand. The species were identified by using MALDI-TOF MS. The minimum inhibitory concentration (MIC) and antibiotic susceptibility were determined. The carbapenemase-producing genes were detected by PCR and whole genome sequencing (WGS). ECC with chromosome-encoded blaIMI-1 carbapenemase were detected. These isolates were resistant to last-resort antibiotics such as carbapenems and colistin as well as penicillin. In addition, all blaIMI-1 genes isolated from this study were found to be associated with chromosomally integrated Xer-dependent integrative mobile elements (IMEXs). Conclusion: These findings highlight the diversity and dissemination of carbapenemases-producing Enterobacterales in environmental sources. With the increasing detection of carbapenemase genes worldwide, we should be aware of the blaIMI-producing E. cloacae complex with a high resistance profile and the ability to mobilize within the environment.