Antibiotic Resistance of Escherichia coli and Klebsiella pneumoniae Isolated from Wild Raccoon Dogs in Shanghai,China

Abstract

Wild animals may act as reservoirs for resistant bacteria, and resident bacteria carried by wild animals in cities may also be subject to anthropogenic pressures that affect their resistance. This study aimed to evaluate the antibiotic susceptibility and biofilm formation ability of Escherichia coli and Klebsiella pneumoniae isolated from wild raccoon dogs from Shanghai, China, and to identify the genes responsible for resistance to different classes of antibiotics. The horizontal transfer of resistant plasmids was assessed by plasmid conjugation assays and characterized by third-generation nanopore sequencing. E. coli and K. pneumoniae isolated from wild raccoon dogs in Shanghai had strong biofilm formation ability. They had high resistance rates to amoxicillin, co-trimoxazole, tetracycline, and other antibiotics, but they were still sensitive to advanced antibiotics. The isolates contained prevalent resistance genes and virulence genes, and plasmids could be transferred horizontally. The resistant plasmids are rich in gene transfer elements such as insertion sequences. This is the first description of the antimicrobial resistance status and genes of wild raccoon dogs in Shanghai. These results highlight the urgent need to understand the origin and spread of resistance genes in wild animals such as urban raccoon dogs in Shanghai.