Serovar Distribution,Virulence Gene Profiles,and Antimicrobial Resistance of Salmonella Isolated from Chicken Meat from the Broiler Slaughterhouse and Processing Plant in Central Thailand
Restricted accessResearch articleFirst published online 2026
Serovar Distribution,Virulence Gene Profiles,and Antimicrobial Resistance of Salmonella Isolated from Chicken Meat from the Broiler Slaughterhouse and Processing Plant in Central Thailand
Salmonella species are among the most important foodborne pathogens of public health concern, described by the World Health Organization as high-priority foodborne pathogen causing a wide range of infections. Salmonella harbors numerous virulence genes (VGs) and antimicrobial resistance (AMR) mechanisms that contribute to its pathogenicity and resistance to antimicrobial agents. Therefore, this cross-sectional surveillance study aimed to assess the prevalence, serovar distribution, VGs, and phenotypic AMR profiles of Salmonella isolated from chicken meat collected from broiler slaughterhouses and a processing plant. A total of 859 chicken meat samples (666 from three slaughterhouses and 193 from a processing plant) were collected and analyzed for Salmonella. The pathogen was detected in 188 of 859 samples (21.9%), with multiple serovars identified among the isolates. The prevalence was 10.9% in the processing plant and ranged from 9 to 39% in slaughterhouses. Salmonella Agona (72/188; 38.30%) and Salmonella Molade (18/188; 9.57%) were frequently detected. Among VGs, sitC was the most prevalent, detected in 98.95% of the isolates, while cdtB was the least, found in 12.23% of the isolates. Antimicrobial susceptibility was tested by disk diffusion for most antibiotics and broth microdilution for colistin, following CLSI M100 (2021) guidelines. Most strains were resistant to ampicillin, streptomycin, gentamicin, trimethoprim–sulfamethoxazole, and tetracycline, with resistance rates of 58.4%, 50.0%, 33.5%, 31.9%, and 30.3%, respectively. Colistin showed the lowest resistance rate (7.4%). In contrast, the isolates exhibited high susceptibility to amoxicillin–clavulanic acid (88.8%) and ceftriaxone (86.2%). Overall, multidrug resistance (MDR) was observed in 45.21% of the isolates. MDR was found across several serovars, especially Salmonella Agona. The high prevalence and diversity of Salmonella and its phenotypic AMR in chicken meat indicate widespread contamination in slaughterhouses and processing plants, underscoring the need for stronger control measures and improved regulation of antimicrobial use in poultry production.
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