Abstract
Class 1 integrons (c1-integrons) are associated with multidrug resistance in diarrheagenic Escherichia coli (DEC). However, little is known about gene cassettes located within these c1-integrons, particularly truncated c1-integrons, in DEC strains. Therefore, the aims of the present study were to reveal the relationship between antimicrobial resistance and the presence of truncated c1-integrons in DEC isolates derived from human stool samples in Japan. A total of 162 human stool-derived DEC isolates from Japan were examined by antimicrobial susceptibility testing, PCR-based gene detection, and next-generation sequencing analyses. Results showed that 44.4% (12/27) of c1-integrons identified in the DEC isolates harbored only intI1 (an element of c1-integrons) and were truncated by IS26, Tn3, or IS1-group insertion sequences. No difference in the frequency of antimicrobial resistance was recorded between intact and truncated c1-integron-positive DEC isolates. Isolates containing intact/truncated c1-integrons, particularly enteroaggregative E. coli isolates, were resistant to a greater number of antimicrobials than isolates without c1-integrons. aadA and dfrA were the most prevalent antimicrobial resistance genes in the intact/truncated c1-integrons examined in this study. Therefore, gene cassettes located within these intact/truncated c1-integrons may only play a limited role in conferring antimicrobial resistance among DEC. However, DEC harboring truncated c1-integrons may be resistant to a greater number of antimicrobials than c1-integron-negative DEC, similar to strains harboring intact c1-integrons.
Highlights
Gene cassettes located within class 1 integrons (c1-integrons) may play an important role in diarrheagenic Escherichia coli (DEC) strains
The aims of the present study were to reveal the relationship between antimicrobial resistance and the presence of truncated c1-integrons in DEC isolates derived from human stool samples in Japan using both conventional sequencing and next-generation sequencing (NGS) analyses
Seven of the ten sequence patterns of cassetteborne antimicrobial and related genes in intact/truncated c1-integrons from strains studied have been identified in other strains from other countries (Table 5), suggesting a worldwide circulation of the c1-integrons among Enterobacteriaceae. e cassette-borne genes identified in the present study suggest that gene cassettes within intact/truncated c1-integrons play a limited role in determining the antimicrobial resistance of Enterobacteriaceae
Summary
Gene cassettes located within class 1 integrons (c1-integrons) may play an important role in diarrheagenic Escherichia coli (DEC) strains. DEC are generally classified into five categories (enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli (STEC), enteroaggregative E. coli (EAEC), and enteroinvasive E. coli) on the basis of their virulence traits [1]. EPEC and EAEC are known for their. Gene cassette qacEΔ1 sul EAEC (n = 3) aadA1 dfrA5 EAEC (n = 1) dfrA17 dfrA1 EPEC (n = 2)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.