Prevalence, Biofilm Formation, and Antibacterial sensitivity of Yersinia enterocolitica Isolated from different types of milk: A Comprehensive Analysis

Yersinia enterocolitica is an emerging foodborne pathogen of significant public health concern, particularly in dairy products. This study aimed to investigate the prevalence, biofilm formation capacity, and antimicrobial resistance patterns of Y. enterocolitica isolated from various types of milk. A total of 100 milk samples comprising cow milk (n=50), milk powder (n=25), and infant formula (n=25) were examined for Y. enterocolitica contamination using conventional bacteriological methods and PCR confirmation targeting the 16S rRNA gene. Biofilm formation was assessed using the microtiter plate method, and antimicrobial susceptibility testing was performed against eight antibiotics using the disk diffusion method. Statistical analysis was conducted using chi-square test. Y. enterocolitica was isolated from 11% (11/100) of the examined samples, with the highest prevalence in milk powder (16.0%), followed by cow milk (12.0%) and infant formula (4.0%). Chi-square analysis revealed no significant difference in prevalence among different milk types (χ² = 2.31, p > 0.05). All isolated strains demonstrated biofilm formation capacity, with 63.6% showing moderate production and 36.4% weak production. Antimicrobial resistance testing revealed complete resistance to amoxicillin-clavulanic acid (100%), high resistance to cefazolin (72.7%) and ampicillin (54.5%), while trimethoprim/sulfamethoxazole showed the highest sensitivity rate (63.6%). Finally, the presence of Y. enterocolitica in milk products, particularly its biofilm-forming ability and multidrug resistance patterns, poses significant food safety concerns. Enhanced surveillance and control measures are essential to prevent foodborne infections, especially in vulnerable populations consuming infant formula.