Antibiotic Resistant and Biofilm-Associated Escherichia coli Isolates from Diarrheic and Healthy Dogs.

Lívia Karahutová,Dobroslava Bujňáková,René Mandelík

doi:10.3390/microorganisms9061334

Abstract

Bacteria isolated from companion animals are attracting concerns in a view of public health including antimicrobial resistance and biofilm development, both contributing to difficult-to-treat infections. The purpose of this study was to evaluate the minimum inhibitory concentrations (MIC) of 18 antibiotics in Escherichia coli isolated from two groups of dogs (healthy and diarrheic). Isolates were classified into phylogroups, examined for the presence of resistance genes and biofilm-formation capacity. In healthy dogs, phylogenetic analysis showed that 47.37% and 34.22% of E. coli isolates belonged to commensal groups (A; B1) in contrast to diarrheic dogs; 42.2% of isolates were identified as the B2 phylogroup, and these E. coli bacteria formed a stronger biofilm. The results of healthy dogs showed higher MIC levels for tetracycline (32 mg/L), ampicillin (64 mg/L), ciprofloxacin (8 mg/L) and trimethoprim-sulphonamide (8 mg/L) compared to clinical breakpoints. The most detected gene encoding plasmid-mediated resistance to quinolones in the healthy group was qnrB, and in dogs with diarrhea, qnrS. The resistance genes were more frequently detected in healthy dogs. The presence of the integron int1 and the transposon tn3 increases the possibility of transfer of many different cassette-associated antibiotic-resistance genes. These results suggest that dogs could be a potential reservoir of resistance genes.

Highlights

Escherichia coli (E. coli) is a highly versatile bacterium that ranges from harmless gut commensal to intra- or extra- intestinal pathogens [1]
A total of 38 E. coli isolates recovered from the fecal samples of healthy non-antimicrobial treated dogs and 45 E. coli isolates from dogs with diarrhea were investigated to phenotypic and genotypic antimicrobial resistance profiles
Resistance gene acquisition is high, and may be due to selection resulting from the resistance gene acquisition is high, and may be due to selection resulting from the frequent frequent of the sulfonamide/trimethoprim combination to its broad-spectrum use of theuse sulfonamide/trimethoprim combination. This may explain the presence of sul1 (n = 1 in the healthy dogs) and sul2 (n = 9 in the healthy dogs and n = 5 in the dogs with diarrhea) genes in our examined isolates. These results indicate a transmission of resistance genes to the normal microflora of healthy dogs

Summary

Introduction

Escherichia coli (E. coli) is a highly versatile bacterium that ranges from harmless gut commensal to intra- or extra- intestinal pathogens [1]. Commensal E. coli colonizes in the gastrointestinal tract within a few hours after birth. These strains are part of the normal microbiota of humans and animals, several clinical reports have implicated. E. coli as the etiological agent of diarrhea in humans and their companion animals [2,3]. Because the contact between humans and pets has increased, the possibility of pathogenic microorganism transmission between these organisms is very high. The fecal shedding of E. coli by companion animals represents an important source of the zoonotic transmission of pathogenic agents [2]

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