Antimicrobial Susceptibility Profiles of Staphylococcus aureus Isolates from Domestic Pigeons in Hungary in 2022.

Abstract

Background: Antimicrobial resistance (AMR) is a critical global health threat, affecting both human and veterinary medicine. Pigeons are increasingly recognized as potential reservoirs of antibiotic-resistant bacteria due to their widespread presence in urban and rural environments. The aim of this study was to determine the antimicrobial susceptibility profiles of Staphylococcus aureus isolates from pigeons in Hungary. Methods: A total of 73 S. aureus isolates were collected from pigeons across seven regions of Hungary in 2022. Minimum inhibitory concentrations (MICs) were determined using the broth microdilution method according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Statistical analysis included correlation heatmaps, hierarchical clustering, network analysis, decision tree modeling, and Monte Carlo simulations. Results: The multidrug-resistant (MDR) prevalence rate was alarmingly high at 80.8%. Very high resistance rates were observed for doxycycline (97.3%), enrofloxacin (87.7%), and amoxicillin (84.9%). By contrast, low resistance rates were detected for vancomycin (5.5%) and imipenem (8.2%). Decision tree modeling identified tiamulin, enrofloxacin, and amoxicillin-clavulanate resistance as the most significant predictors of MDR status. Monte Carlo simulations predicted a mean MDR prevalence of 78.5%, indicating that the dominance of MDR strains is not merely a random phenomenon but part of a broader epidemiological pattern. Conclusions: These findings confirm that pigeons may serve as critical reservoirs of MDR S. aureus strains, posing a potential risk to public and animal health. Continued monitoring, the genetic characterization of resistant strains, and the development of effective control strategies are urgently needed. This study provides a foundation for future research aimed at understanding the biological, ecological, and epidemiological roles of pigeon-associated MDR strains.