Virulence determinant and antimicrobial resistance traits of Emerging MDR Shiga toxigenic E. coli in diarrheic dogs

Shiga-toxigenic Escherichia coli (STEC) is incriminated in severe hemorrhagic enteritis in dogs, which is considered a veterinary and public health alarm. To investigate the prevalence, antimicrobial resistance patterns, virulence determinants, and distribution of antimicrobial resistance genes in STEC strains isolated from dogs: 80 fecal samples were obtained from diseased dogs suffering from hemorrhagic diarrhea from pet animal clinics in Ismailia governorate, Egypt. The obtained samples were examined bacteriologically. Moreover, the retrieved isolates were tested for serogrouping, Congo-red binding, antimicrobial resistance, and PCR-based determination of virulence and antimicrobial resistance genes. The prevalence of E. coli in the examined diseased dogs was 23.75% (19/80). The serogrouping of the recovered isolates revealed that 84.2% of the tested isolates were distributed into three serogroups: O146 (36.8%), O111 (31.5%), and O26 (15.7%). Meanwhile, three isolates were untypable (15.8%). Moreover, all the tested E. coli serovars were positive for CR-binding. PCR revealed that the prevalence of stx 1, eae A, hly A, and stx 2 virulence genes was 100%, 100%, 100%, and 47.3%, respectively. Our findings revealed that 31.5% of the recovered isolates showed MDR to five antimicrobial classes and harbored bla TEM , bla CTX-M , tet A, tet B, and sul 1 genes. Alarmingly, three isolates were carbapenem-resistant. Two strains harbored the bla KPC gene, while one strain carried the bla NDM-1 gene. Concisely, as far as we know, this is the first study that reported the existence of MDR-STEC in dogs in Egypt. The stx 1 gene is the most predominant Shiga toxin gene that accompanied the STEC isolated from hemorrhagic enteritis in dogs. The emerging MDR-STEC in dogs commonly harbors bla TEM , bla CTX-M , sul 1, tet A, tet B, and qnr A resistance genes. Meropenem, levofloxacin, and tigecycline exhibited talented antimicrobial activity against MDR-STEC isolated from dogs.