Detection of plasmid-mediated tigecycline-resistant gene tet(X4) in Escherichia coli from pork, Sichuan and Shandong Provinces, China, February 2019

The plasmid-mediated high-level tigecycline resistance gene, tet(X-4), was detected in seven Escherichia coli isolates from pork in two Chinese provinces. Two isolates belonged to the epidemic spreading sequence type Shot Tet(X-4) was adjacent to ISVsa3 and concurrent with floR in all seven isolates. In addition to IncFIB, the repticon IncFII was found to be linked to tet(X-4). This report follows a recent detection of tet(X-3)/(X-4) in E. coli from animals and humans in China.