Veterinary session

The importance of antimicrobial resistance in the 21st century in the context of One Health underlines the need for regular antimicrobial testing, particularly in certain areas of the poultry sector. Pigeons are a minor food-producing animal whose role is often underestimated, even though they can make a significant contribution to the spread of resistance by travelling long distances.

The aim of our research was to determine the sensitivity of nationally collected Escherichia coli strains isolated from domestic pigeon flocks to active substances of animal and public health importance by determining their minimum inhibitory concentration (MIC) values. An epidemiological breakpoint (ECOFF) was then determined for those agents where the bimodal distribution of the data allowed.

A total of 134 Escherichia coli strains isolated from pigeons were tested and 2010 MIC values were determined. A resistance rate of 82.8% was observed for amoxicillin, but only 55.2% for the drug amoxicillin-clavulanic acid, confirming the presence of β-lactamase producing strains that are very common in Escherichia coli. ECOFF values of 64 µg/ml and 128 µg/ml were found for the former and the latter respectively. Ceftriaxone also showed a high level of resistance (43.3%), whereas the ECOFF value of 0.125 µg/ml was in line with the breakpoint established by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). For imipenem, only 7.5% of strains were resistant, but an ECOFF of 2 µg/ml was determined. For neomycin, the resistance of 91.8% was very high, with an ECOFF value of 256 µg/ml, which our results support the overuse of aminoglycosides in veterinary medicine for several decades. Resistance was found to be 44.8% for spectinomycin and 65.7% for doxycycline. Among the critically important active substances, 21.6% resistance was detected for enrofloxacin, while the defined ECOFF was very high at 32 µg/ml. For colistin, the observed resistance was 11.2% and our ECOFF was close to the internationally observed value of 4 µg/ml. For potential sulphonamide, however, we observed 100% resistance, which in turn shows a much worse situation compared to other countries.

In conclusion, our results support the justification for regular surveys in pigeons. In many cases, we obtained similar results to those reported in the literature, the differences being explained by different antibiotic use.