Comparative Genome Analysis of Livestock and Human Colistin-Resistant Isolates from the Same Household.

BACKGROUND

Emergence and dissemination of colistin-resistant bacteria that harbor mobile colistin resistance () genes pose a dire challenge for the treatment of intractable infections caused by multidrug-resistant bacteria. Current findings on colistin-resistant bacteria in both humans and livestock of the same households highlight the need to identify the dissemination mechanisms of colistin-resistant bacteria.

METHODS

In this study, a comparative genome analysis of colistin-resistant isolates from livestock and humans of the same household was performed to clarify the possible dissemination mechanism of genes among bacteria. Pulsed-field gel electrophoresis and whole-genome sequencing followed by sequence typing of the isolates were performed for assessment of the samples.

RESULTS

The study revealed that two colistin-resistant isolates, one each from a pig and a chicken, were phylogenetically similar but not identical to the human isolates obtained from the same household. The comparative genome analysis revealed that the chicken isolate and a human isolate shared the same IncHl2 plasmid harboring the transposon (-PAP2). The pig isolate and the other human isolate retained the transposon on the chromosome, with the pig isolate carrying the complete transposon (IS-IS) and the human isolate carrying the incomplete transposon (IS).

CONCLUSION

The results of the study confirm the distribution of colistin-resistant bacteria and subsequent transmission of the resistance gene-carrying transposon between livestock and humans of the same household. To the best of our knowledge, this is the first report on genomic analysis of colistin-resistant isolates obtained from livestock and residents of the same household.