Background: The Shiga toxin-producing Escherichia coli (STEC) represented a great risk to public health. In this
study, 60 STEC strains recovered from broiler and duck fecal samples, cow’s milk, cattle beef, human urine, and ear
discharge were screened for 12 virulence genes, phenotypic and genotypic antimicrobial resistance, and multiplelocus
variable-number tandem-repeat analysis (MLVA).
Results: The majority of strains harbored Shiga toxin 1 (stx1) and stx1d, stx2 and stx2e, and ehxA genes, while a
minority harbored stx2c subtype and eaeA. We identified 10 stx gene combinations; most of strains 31/60 (51.7%)
exhibited four copies of stx genes, namely the stx1, stx1d, stx2, and stx2e, and the strains exhibited a high range of
multiple antimicrobial resistance indices. The resistance genes blaCTX-M-1 and blaTEM were detected. For the
oxytetracycline resistance genes, most of strains contained tetA, tetB, tetE, and tetG while the tetC was present at
low frequency. MLVA genotyping resolved 26 unique genotypes; genotype 21 was highly prevalent. The six highly
discriminatory loci DI = 0.9138 are suitable for the preliminary genotyping of STEC from animals and humans. |
