Methodology. In March 2014, a total of 66 faecal samples were recovered from independent animals. Antibiotic resistance was determined by the disc diffusion method. Carriage of genes coding for antibiotic-resistant and virulent factors was analysed by PCR.
Results. A total of 66 E. coli and 41 enterococcal isolates were detected, with Enterococcus faecium (61 %) and Enterococcus hirae (24 %) being the most prevalent species. For enterococcal isolates, high percentages of resistance rates to tetracycline (68.3 %), quinupristin/dalfopristin (51.2 %) and ciprofloxacin (48.8 %) were observed. The genes erm(A) and/or erm(B), tet(M) and/or tet(L), vat(D) and/or vat(E) and aph(3′)-IIIa were also found. The most frequent virulence gene detected was gel(E), followed by ace, cpd and hyl. Escherichia coli isolates were highly resistant to streptomycin (78 %), whereas 39 % of them exhibited resistance to aminoglycosides and tetracycline. Genes sul1 and/or sul2 were detected in 66.7 % of trimethoprim/sulfamethoxazole-resistant isolates. The virulence genes detected were fim(A) (46 %) and cnf1 (27 %).
Conclusion.. To the best of our knowledge, this is the first report showing antibiotic resistance among Escherichia coli and Enterococcus spp. isolates from the Miranda donkey in Portugal, indicating possible antibiotic-resistant bacterial reservoirs. However, the detection of these resistances presents a low risk for other animals and human beings in that rural area.
- antimicrobial resistance
- Enterococcus spp
- Equus asinus
- Escherichia coli
- virulence genes