TDK conference 2025

The Hungarian waterfowl sector holds considerable importance from a veterinary perspective due to the high prevalence of infectious diseases associated with intensive production systems, which in turn leads to substantial antibiotic usage. This creates an increased risk of antimicrobial resistance (AMR), posing serious consequences not only for animal health but also for food chain safety and public health.

In our study, we investigated the antimicrobial susceptibility patterns of six pathogenic bacterial species isolated from clinical cases in waterfowl: Escherichia coli, Salmonella spp., Pasteurella multocida, Riemerella anatipestifer, Erysipelothrix rhusiopathiae, and Streptococcus gallolyticus. During the laboratory susceptibility testing, we determined the minimum inhibitory concentration (MIC) values for 15 different antimicrobial agents and calculated MIC₅₀ and MIC₉₀ values.

The results showed that Escherichia coli strains exhibited exceptionally high resistance to amoxicillin, doxycycline, enrofloxacin, and potentiated sulfonamides. In contrast, Salmonella spp. isolates demonstrated high overall susceptibility, though resistance to amoxicillin, doxycycline, and colistin were notable. Riemerella anatipestifer strains displayed elevated resistance specifically to enrofloxacin. All Pasteurella multocida strains tested were susceptible to amoxicillin, while Erysipelothrix rhusiopathiae isolates were broadly sensitive to nearly all tested antibiotics, with the exception of increased resistance to oxytetracycline. Streptococcus gallolyticus isolates showed widespread resistance to oxytetracycline, but excellent susceptibility to penicillins.

These findings confirm the growing presence of multidrug-resistant bacterial species in the waterfowl production sector, which not only compromises the effectiveness of therapeutic protocols but also poses significant zoonotic and public health risks. The study highlights the urgent need to strengthen national surveillance systems, particularly to support prudent antimicrobial use, ensure food chain safety, and combat AMR more effectively.