Edible river fish-derived extended-spectrum β-lactamase (ESBL)-producing Enterobacterales harboring transferable plasmids encoding blaCTX-M-15, blaCTX-M-27, and blaCTX-M-55

Abstract

Transmission of extended-spectrum β-lactamase (ESBL) genes has increased the global prevalence of ESBL-producing bacteria, especially in developing countries. Human infection with these bacteria may be food-mediated but has not been fully elucidated. Therefore, we aimed to examine ESBL-producing bacteria in edible river fish and elucidate their potential for horizontal gene transfer. A total of 173 ESBL-producing Enterobacterales were isolated (Escherichia coli [n = 87], Klebsiella pneumoniae [n = 52], Enterobacter cloacae complex [n = 18], Citrobacter freundii complex [n = 14], Atlantibacter hermannii [n = 1] and Serratia fonticola [n = 1]) from 56 of 80 fish intestinal contents sampled. Among the bacterial blaCTX-M genotypes, blaCTX-M-55 was the most predominant, followed by blaCTX-M-15, blaCTX-M-27, and blaCTX-M-65. Furthermore, we found that ESBL-producing Enterobacterales were able to transfer their blaCTX-M genes to E. coli. In summary, our results suggest that ESBL-producing Enterobacterales transfer blaCTX-M to indigenous gut E. coli in humans, following the consumption of contaminated fish.

Keywords

• Plasmid-mediated antibiotic resistance
• Extended-spectrum β-lactamase-producing Enterobacterales
• blaCTX-M-55
• Vietnamese edible fish
• Horizontal gene transfer