Intact pap2 downstream of mcr-1 appears to be required for colistin resistance

In this study, we investigated the effect of pap2 on colistin susceptibility using intact pap2 and truncated pap2 (pap2∆351) genes, which were found along with mcr-1 in plasmid. Our experiments based on conjugation, antibiotic susceptibility testing, and time-killing assay showed that an intact pap2 gene is necessary along with mcr-1 for reduced colistin susceptibility.