Identification and characterization of Escherichia coli strains producing a novel Shiga toxin 2k subtype in goat feces in Lanling county, Shandong province / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the prevalence and molecular characteristics of Escherichia coli ( E. coli) producing a novel Shiga toxin 2k subtype in goat in Lanling county, Shandong province. Methods:In November 2019, 512 goat fecal samples were collected from different households in Lanling county, Shandong province. After enriched with EC broth, stx-positive samples were detected by PCR and inoculated in CHROMagar? ECC agar and CHROMagar? STEC agar. The whole genomes of stx-positive strains were sequenced. Based on the genomic senquences, the stx subtype, serotype, multi-locus sequence type and virulence genes of each strain were analyzed. Results:Eighty-six strains of Shiga toxin-producing E. coli (STEC) were isolated from 512 goat fecal samples. Five stx subtypes were identified and 37 strains were positive for stx2k. The 86 STEC strains belonged to 20 O∶H serotypes and 18 different sequence types (STs). Conclusions:STEC strains circulating in goats in Lanling county, Shandong province were heterogeneous in stx subtypes, serotypes and virulence gene profiles, and a certain proportion of strains producing a novel Shiga toxin 2k subtype were detected.