Abstract: [Objective] This study was conducted to understand the prevalence of virulence and antimicrobial resistance genes in Escherichia coli （E. coli） strains derived from diarrheal lambs in large-scale sheep farms in Hotan Prefecture, Xinjiang Uygur Autonomous Region, China. [Method] A total of 70 anal swabs of diarrheal lambs were sampled from 3 large-scale sheep farms in Hotan Prefecture. Traditional methods such as bacterial isolation and culture, staining and microscopy, biochemical identification, and 16S rDNA PCR amplification and sequencing were used to isolate and identify E. coli strains in the samples. PCR assay was employed for phylogenetic grouping of E. coli strains, as well as detection of virulence and antimicrobial resistance genes. [Result] Through morphological observation, biochemical identification, and 16S rDNA sequence analysis, a total of 38 strains of E. coli were isolated and identified from the 70 anal swabs of diarrheal lambs, with a separation rate of 54.3% （38/70）. Phylogenetic grouping analysis showed that B1 group was the dominant group （68.4%, 26/38） of the isolated strains, followed by A group （26.3%, 10/38） and D group （5.3%, 2/38）, and B2 group was not detected. The results of virulence gene testing showed that 4 out of 8 E. coli virulence genes were detected, and the proportion of fimC gene carrying strains were the highest at 92.1% （35/38）, followed by irp2 gene at 47.4% （18/38）, hlyF gene at 36.8% （14/38）, and fyuA gene at 34.2% （13/38）; the genes of eaeA, ST, LT and Stx1 were not detected. The results of antimicrobial resistance gene testing showed that 6 out of 8 E. coli resistance genes were detected, with the carrying rate of sulfonamide resistance gene sul2 being the highest at 42.1% （16/38）; no aminoglycoside resistance genes were detected. [Conclusion] The E. coli strains from diarrheal lambs in Hotan Prefecture harbor virulence and antimicrobial resistance genes. The prevalence of pathogenic E. coli of sheep origin in this region should be monitored.

Key words: Escherichia coli, identification, virulence, antimicrobial resistance, diarrheal lamb