Integrated Surveillance of Listeria monocytogenes in Food Products of Dakahlia, Egypt: Prevalence, Risk Factors, and One-Health Implications

Listeria monocytogenes (L. monocytogenes) represents a critical foodborne pathogen with extraordinary environmental resilience and severe clinical impact, particularly affecting immunocompromised individuals, pregnant women, neonates, and the elderly person. This study aimed to elucidate the prevalence, molecular characteristics, and antimicrobial resistance profiles of L. monocytogenes across diverse food supply products in Dakahlia Governorate, Egypt, while evaluating the efficacy of advanced cold enrichment protocols for pathogen recovery. This study was conducted with 500 samples systematically collected from retail markets (n=150), supermarkets (n=150), slaughterhouses (n=100), and dairy farms (n=100). Isolation and identification, incorporating dual enrichment and advanced cold enrichment protocol were performed. Biochemical, phenotypic, and molecular (PCR-based) assays targeted key virulence genes (prfA, hlyA) were conducted. Antimicrobial susceptibility was assessed using CLSI M45 guidelines, and statistical analyses explored contamination dynamics and risk factors. L. monocytogenes was isolated from 4.20% of samples (95% CI: 2.76-6.34%), with the highest prevalence in dairy farms (7.00%) and high-risk food categories including minced meat (7.94%), cream (7.89%), yogurt (7.69%), and milk (7.00%). The cold enrichment protocol enhanced detection sensitivity significantly. All isolates harbored both prfA and hlyA virulence genes, confirming high pathogenic potential. Alarmingly, isolates exhibited near-universal resistance to β-lactams and high multidrug resistance rates (85.7-90.5%), while maintaining complete susceptibility to gentamicin, imipenem, and linezolid. This study highlights the urgent public health threat posed by multidrug-resistant L. monocytogenes in Egyptian food supply products. The findings underscore the necessity for advanced molecular surveillance, stringent antimicrobial stewardship, and integrated One Health interventions to safeguard food safety and public health.