TDK conference 2024

In recent decades, the widespread emergence of antimicrobial resistance has been observed, closely linked to the overuse and often improper application of antibiotics. Intensive animal farming contributes to the spread of pathogenic microorganisms, and the study of microbial resistance is becoming increasingly important for both animal and public health.

Our aim was to assess the sensitivity of commensal Enterococcus strains isolated from large turkey flocks in Hungary to antibiotic agents that are significant for animal and public health by determining the minimum inhibitory concentration (MIC) values. Following this, we created frequency tables from our results, and we determined MIC50 and MIC90 values for the study population per agents. We compared our findings with international epidemiological cut-off values (ECOFF) and performed an indicative ECOFF determination. Finally, we compared these results with human resistance data.

We conducted susceptibility testing on 470 strains from seven regional administrative units in Hungary. A correlation study between the resistance levels to the different antibiotics revealed a high positive correlation in several cases (e.g., between amoxicillin and amoxicillin-clavulanic acid, and between amoxicillin and vancomycin), suggesting a connection in the resistance patterns of Enterococcus species to these antibiotics. The purpose of use was a significant factor in determining resistance levels for most of the tested antibiotics, showing notable differences. The majority of strains remained sensitive to amoxicillin, showing a resistance rate of only 11.1%. The highest resistance rates were found against tylosin (62.6%) and florfenicol (51.1%). When comparing our results with human resistance data, we found the greatest similarity in resistance levels to aminoglycoside antibiotics.

Our findings underscore the significance of systematic survey studies and the importance of comparing data with human resistance information. Regular repetition of these studies allows monitoring of trends over time. In cases of multi-resistant strains, further investigation of the genetic background of resistance using next-generation sequencing is warranted.