Carbapenemase and ESBL genes with class 1 integron among fermenting and nonfermenting bacteria isolated from water sources from India

The present study was aimed to detect the carbapenemase, extended-spectrum β-lactamase (ESBL), and intI1 gene of class 1 integron among fermenting (n = 61) and nonfermenting (n = 10) bacterial isolates recovered from water samples (n = 128). Isolates were identified by 16S rRNA sequencing. These isolates showed reduced-susceptibility to third-generation cephalosporins and carbapenems. The isolates varied in number and size of plasmids (2 kb to >20 kb). Plasmid DNA screening showed 5·6, 7, 11·2 and 26·7% prevalence of blaKPC , blaNDM , blaSHV and blaTEM genes respectively. Diverse blaNDM (blaNDM-1 and blaNDM-4 ) and blaSHV subtypes (blaSHV-2 and blaSHV-11 ) were recorded, unlike the single allelic blaKPC (blaKPC-2 ) and blaTEM (blaTEM-1 ) gene. Of the total 27 bla-gene-producing bacterial isolates, seven isolates co-harboured the carbapenemase genes (blaNDM or blaKPC or the both) along with the ESBL genes (blaSHV or blaTEM ). The intI1 gene of class 1 integron was detected among 12 (44·4%) of ESBL- and/or carbapenemase-harbouring isolates. Gene transferability was seen among four of the 10 Enterobacteriaceae donors. Carbapenemases and ESBLs with class 1 integron among aquatic environmental isolates raise the serious issue of the biosecurity and health of the ecosystem. SIGNIFICANCE AND IMPACT OF THE STUDY: Anthropologically affected and polluted environment harbours the resistance threats, where a diverse bacterial species maintain, develop and exchange genetic determinants that constitute a risk to human and ecological health. The antimicrobial resistance (AMR) in Enterobacteriaceae and non-Enterobacteriaceae bacteria caused the failure of the therapy of last resort (carbapenems) and thus lead to life-threatening infections affecting public health. Surveillance and monitoring of AMR could be important for epidemiological, diagnostic testing and control of pathogens. This is a point-prevalence study reporting the comparative occurrence and co-occurrence of carbapenemase and extended-spectrum β-lactamase genes among fermenting and nonfermenting bacteria isolated from the aquatic environment in India.