Our study shows how evolution can rapidly stabilize resistance genes in pathogen populations, reducing the impact of restricting antibiotic consumption. In 2017, the Chinese government banned the use of last-line antibiotic colistin as a growth promotor in animal feed in response to the rapid spread of antibiotic resistant bacteria- Escherichia coli (E.coli) carrying mobile colistin resistance (MCR) genes. However, large-scale surveillance studies across China following the ban found that the decline in the mcr-1 gene was slower than anticipated. Overuse of antibiotics in livestock farming is a key driver of antimicrobial resistance (AMR). Simply put, it is not enough to reduce antibiotic consumption in order to effectively combat antibiotic resistance.