Molecular Insights and Antibiotic Resistance of Proteus mirabilis from Retail Meat Sources in Iran.

Proteus mirabilis (P. mirabilis) is an emerging foodborne pathogen that poses a risk to both veterinary and human health because of its virulence factors and multidrug resistance (MDR) capability. This study aimed to investigate the molecular characteristics, virulence genes, antibiotic resistance, and genetic diversity of P. mirabilis isolated from red meat and poultry in Shahrekord, Iran. A total of 480 meat samples (red meat and poultry) were examined for P. mirabilis contamination using biochemical and molecular methods. Biofilm formation was evaluated using the microtiter plate assay. Antibiotic susceptibility was determined by the disk diffusion method. Extended-spectrum β-lactamase (ESBL) production was detected by the combined disk test. Resistance and virulence genes were identified by PCR. Genetic diversity was analyzed using Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR) and Repetitive Extragenic Palindromic-Polymerase Chain Reaction (REP-PCR). Out of 480 samples, 92 (19.16%) were positive for P. mirabilis, with the highest prevalence in veal (25%) and chicken (27.5%). Over 79% of isolates were strong biofilm producers. The highest resistance rates were observed for nitrofurantoin (70.8%) and trimethoprim-sulfamethoxazole (79.5%). ESBL-producing isolates carried blaCTX-M and blaTEM genes, whereas blaSHV was less frequent. The most common resistance genes were qnrA, qnrB, tetA, tetB, and sul1. Virulence genes such as zapA, hpmA, mrpA, and hlyA were detected in most isolates. ERIC-PCR and REP-PCR revealed high genetic diversity among isolates with 75%-100% similarity for red meat isolates and 51%-100% for poultry isolates. P. mirabilis isolates from red meat and poultry in Shahrekord showed high prevalence of MDR and virulence genes, indicating potential risks to food safety and public health. Continuous monitoring and stricter control measures in meat production are necessary to prevent the spread of resistant and virulent strains.