Detection and dissemination of the colistin resistance gene, mcr-1, from isolates and faecal samples in China.

PURPOSE: A recently identified colistin resistance gene, mcr-1, has been reported in many countries. In this study, we established a new real-time PCR method to detect it.

METHODOLOGY: We used a real-time PCR method to detect the mcr-1 gene in a variety of isolates and faecal samples from 20 provinces and municipal cities in China.

RESULTS: Of the 2330 isolates (from 10 species) screened, 54 (2.3 %) isolates were positive for mcr-1. All of the mcr-1-positive isolates that were identified belonged to Escherichia coli strains, among which 9, 1, and 44 were identified as enteropathogenic E. coli, enteroadherent E. coli, and non-pathogenic E. coli, respectively. The majority of the mcr-1-positive isolates were obtained from farm animals from eight provinces and municipal cities across China. A total of 337 faecal samples, including 229 human and 108 pet animal faecal samples, were also screened for the mcr-1 gene. Of the 337 samples analyzed, six and eight human and pet animal faecal samples were positive for the mcr-1 gene, respectively.

CONCLUSION: The data demonstrate that the mcr-1 gene is highly prevalent in human and animal populations in China. This occurrence suggests that active surveillance of the mcr-1 gene is imperative in curtailing its spread.