Antibiotic resistance profiles and genomic analysis of Klebsiella pneumoniae ST15 with mcr-1 gene isolated from mink in China

BACKGROUND: Klebsiella pneumoniae (K. pneumoniae) is a zoonotic opportunistic pathogen that can cause pneumonia in minks, significantly impacting the mink breeding industry. In this study, a K. pneumoniae strain carrying the mcr-1 gene was isolated from mink in Shandong Province, China. To investigate its genetic composition and resistance mechanisms, antimicrobial susceptibility testing and whole-genome sequencing were conducted. RESULTS: The results revealed that K. pneumonia strain was ST15, with serotypes KL24 and O1/02V1. Antimicrobial susceptibility testing showed that the strain was multi-drug resistant. The ST15 isolate carried several resistance genes, which correlated with its resistance profile. Two plasmids, classified as IncHI2 and IncR, were identified in the strain. The mcr-1 gene was located on the IncHI2 plasmid, which also harbored other resistance genes. Another plasmid was found to carry additional drug resistance genes, contributing to the strain’s broad-spectrum resistance phenotype. Upstream of the mcr-1 gene is the ISApl1, which is closely associated with the dissemination of the mcr-1 gene in K. pneumoniae strain. CONCLUSION: This study reported the presence of the mcr-1 gene in an ST15 K. pneumoniae strain isolated from mink. The findings highlight the role of antibiotic resistance and the riskiness of K. pneumoniae from animals harboring the mcr-1 gene.