The occurrence and molecular detection of mcr-1 and mcr-5 genes in Enterobacteriaceae isolated from poultry and poultry meats in Malaysia.

The advent of antimicrobials-resistant (AMR), including colistin-resistant bacteria, poses a significant challenge to animal and human health, food safety, socio-economic growth, and the global environment. This study aimed to ascertain the colistin resistance prevalence and molecular mechanisms of colistin resistance in . The colistin resistance was determined using broth microdilution assay, PCR; and Sanger sequencing of genes responsible for colistin resistance in ( = 627), including (436) spp. ( = 140), and ( = 51), obtained from chicken and chicken meats. Out of 627 , 8.6% of isolates exhibited colistin resistance phenotypically. Among these colistin resistant isolates, 9.3% ( = 37) were isolated from chicken meat, 7.2% ( = 11) from the cloacal swab of chicken and 7.9% ( = 6) from the litter samples. Overall, 12.96% of colistin-resistant isolates were positive with genes, in which and genes were determined in 11.11% and 1.85% of colistin-resistant isolates, respectively. The isolates obtained from chicken meats, cloacal swabs and litter samples were found positive for , and spp. originated from the chicken meat sample was observed with , whereas no genes were observed in strains isolated from any of the collected samples. The other colistin resistance genes, including and were not detected in the studied samples. The and genes were sequenced and found to be 100% identical to the and gene sequences available in the NCBI database. This is the first report of colistin resistance gene in Malaysia which could portend the emergence of harboring bacterial strains for infection. Further studies are needed to characterize the harbouring bacteria for the determination of plasmid associated with gene.