Zoonotic threat of Proteus mirabilis in Xinjiang swine: antimicrobial resistance and virulence risks

Proteus mirabilis ( P. mirabilis ) is an opportunistic pathogen causing zoonotic diseases like diarrhea, keratitis, and urinary tract infections, sometimes leading to animal miscarriages. This study examined P. mirabilis prevalence in Xinjiang’s pig farms and pork, analyzing its drug resistance and pathogenicity to address food safety concerns. From 216 samples, 42 P. mirabilis strains were isolated (19.44%, 42/216), mostly from pig farms (95.24%, 40/42) rather than pork (4.76%, 2/42). All strains were multidrug-resistant, showing over 90.00% resistance to sulfonamides, tetracyclines, chloramphenicol, macrolides, polypeptides, and glycopeptides. Among them, 54.76% (23/42) produced extended-spectrum β-lactamases (ESBLs), enhancing resistance. The strains carried 19 resistance genes (7 categories), with CTX and OXA type ESBL related resistance genes exceeding 30.00% detection rate. Additionally, 95.24% (40/42) of the isolated strains carried class I integron genes. Nine virulence genes ( ureC , zapA , atfA , ucaA , pmfA , mrpA , r sbA , fliL , and hpmA ) were identified, and most strains (80.95%, 34/42) had strong biofilm-forming ability. These findings indicate that multidrug-resistant P. mirabilis in pigs, carrying diverse resistance and virulence genes, may spread via the food chain, posing health risks to consumers.