Antimicrobial Resistance in Commensal Bacteria from Large-Scale Chicken Flocks in the Dél-Alföld Region of Hungary

<b>Background</b>: Antimicrobial resistance (AMR) is increasingly acknowledged as a critical global challenge, posing serious risks to human and animal health and potentially disrupting poultry production systems. Commensal bacteria such as <i>Staphylococcus</i> spp., <i>Enterococcus</i> spp., and <i>Escherichia coli</i> may serve as important reservoirs and vectors of resistance genes. <b>Objectives</b>: This study aimed to assess the AMR profiles of bacterial strains isolated from industrial chicken farms in the Dél-Alföld region of Hungary, providing region-specific insights into resistance dynamics. <b>Methods</b>: A total of 145 isolates, including <i>Staphylococcus</i> spp., <i>Enterococcus</i> spp., and <i>E. coli</i> isolates, were subjected to minimum inhibitory concentration (MIC) testing against 15 antimicrobial agents, following Clinical and Laboratory Standards Institute (CLSI) guidelines. Advanced multivariate statistics, machine learning algorithms, and network-based approaches were employed to analyze resistance patterns and co-resistance associations. <b>Results</b> Multidrug resistance (MDR) was identified in 43.9% of <i>Staphylococcus</i> spp. isolates, 28.8% of <i>Enterococcus</i> spp. isolates, and 75.6% of <i>E. coli</i> isolates. High levels of resistance to florfenicol, enrofloxacin, and potentiated sulfonamides were observed, whereas susceptibility to critical antimicrobials such as imipenem and vancomycin remained largely preserved. <b>Discussion</b>: Our findings underscore the necessity of implementing region-specific AMR monitoring programs and strengthening multidisciplinary collaboration within the "One Health" framework with proper animal hygiene and biosecurity measures to limit the spread of antimicrobial resistance and protect both animal and human health.