Abstract: [Objective] The aim of the present study was to characterize the antimicrobial resistance profile as well as the prevalence of CTX-M gene and virulence genes of the Escherichia coli （E. coli） strains derived from cattle in Ta′e reclamation area, Xinjiang Uygur Autonomous Region. [Method] A total of 16 fecal samples of cattle with diarrhea were collected from a cattle farm in Ta′e reclamation area. The selective culture, Gram staining and microscopy, and 16S rDNA PCR amplification and sequencing were used to isolate and identify the E. coli strains. The PCR assay was used for the molecular typing （phylogenetic group and lipopolysaccharide core type） as well as the detection of antimicrobial resistance genes, CTX-M gene subtypes and virulence genes of the E. coli isolates. The K-B disk diffusion method as well as the CTX and TCL dual disk diffusion method were utilized for antimicrobial sensitivity test and ESBLs-producing E. coli identification, respectively. The biofilm formation ability of the E. coli isolates were semi-quantitatively analyzed using crystal violet staining method.[Result] Based on the colony growth feature, Gram staining characteristic and 16S rDNA sequencing result, a total of 16 E. coli strains were isolated and identified from the 16 fecal samples of the diarrhoeal cattle, with a separation rate of 100%. Most of the E. coli isolates belonged to the phylogenetic group B1 （14/16, 87.50%） and the lipopolysaccharide core type R1 （15/16, 93.75%）. The E. coli isolates exhibited high-level resistance to penicillin, rifampicin and compound sulfamethoxazole, with resistance rates of 100%, 68.75% and 68.75%, respectively, while they were sensitive to polymyxin, tigecycline and meropenem, with resistance rates all being 0. Twelve strains （75.00%） had multi-drug resistant phenotype, 11 strains （68.75%） produced ESBLs, and 15 strains （93.75%） were capable of forming biofilm. A total of 17 antimicrobial resistance genes were detected as positive among the 16 E. coli isolates, and the detection rates for 8 antimicrobial resistance genes such as CTX-M, ant （6′） and sul1 were 100%. Fourteen strains （87.50%） were identified as the CTX-M-1G gene subtype. In addition, a total of 12 virulence genes were detected as positive, among which, 5 virulence genes including iroN, ompA and yijP had 100% detection rate.[Conclusion] A high prevalence of CTX-M gene was observed in the cattle derived E. coli strains in Ta′e reclamation area of Xinjiang Uygur Autonomous Region. Furthermore, these isolates harbored multiple antimicrobial resistance genes and virulence genes, and had high-level antimicrobial resistance, which posed potential threats to the healthy farming of cattle in this region. Therefore,it is necessary to strengthen the monitoring of the CTX-M type E. coli prevalence in this region.

Key words: Escherichia coli, CTX-M gene, molecular typing, antimicrobial resistance, virulence gene