Transfer of antimicrobial resistant genes of ESBL-producing Escherichia coli recovered from a wastewater treatment plant

Abstract:

[Objective] We explored the role of mobile plasmids in transferring antimicrobial resistant genes in extended-spectrum beta-lactamases (ESBLs)-producing Escherichia coli from a wastewater treatment plant. [Methods] Based on the conjugation experiments of ESBL-producing E. coli collected from wastewater, the disk diffusion assay and polymerase chain reaction (PCR) were used to determine the transfer of antimicrobial resistance. [Results] A total of 50 ESBL-producing E. coli were collected from 80 water samples (50/80, 62.5%), and successful conjugations were detected among 35 isolates (35/70, 70.0%). The results of PCR further showed that bla_CTX-M and bla_TEM genes were all capable of conjugation transfer, but the horizontal transfer of bla_SHV gene was only detected in one isolate and resistance gene encoding fluoroquinolone was not capable of conjugation transfer in this study. [Conclusions] Plasmids carrying different antimicrobial resistant genes may exhibit different capacity of horizontal transfer. Importantly, the mobile plasmids played a very important role in the horizontal transfer of antimicrobial resistance genes of ESBL-producing E. coli.

Key words:extended-spectrum beta-lactamases;Escherichia coli;antimicrobial resistance genes;plasmid;conjugation;horizontal transfers