A colistin-resistant strain isolated from dog feces was characterized in this study. A multiplex PCR assay was used to detect the presence of colistin-resistant genes; it was found that QDFD216 co-harbored the and genes. Whole-genome sequencing and further bioinformatics analysis revealed that QDFD216 belonged to serotype O176:H11, fimH1311 type and ST132. The resistance genes , , and were present in the chromosome. The and genes were located in two plasmids of different incompatibility groups. was carried by a IncX4-type plasmid within an typical IS cassette, while was encoded by an IncP1-type plasmid with a genetic structure of Tn -IS . No additional antibiotic resistance genes were carried by either plasmid. This is the first report of an isolate co-harboring a -carrying IncX4 plasmid and a -carrying IncP1 plasmid. The evolution and mechanism of gene co-existence need further study to assess its impact on public health.