Carriage of the mcr-9 and mcr-10 genes in clinical strains of the Enterobacter cloacae complex in China: a prevalence and molecular epidemiology study

•This study was a longitudinal, large-scale surveillance of mcr-9 and mcr-10 in Enterobacter cloacae complex in China.•Enterobacter cloacae complex strains may be important reservoirs of mcr-9.•mcr-9 often coexisted with carbapenemase genes and they had the potential for co-transfer.•The mcr-9- and mcr-10-positive strains exhibited extreme genetic diversity.•Plasmids played an important role in the transmission of mcr in Enterobacter cloacae complex.