Genetic Diversity, Antibiotic Resistance, and Pathogenicity of Species from Food Products in Shanghai, China.

Objective: has recently been recognized as an emerging human pathogen. -associated diarrhea is a phenomenon occurring worldwide. This study was designed to determine the prevalence, genetic diversity, antibiotic resistance, and pathogenicity of strains isolated from food products in Shanghai.

Methods: isolates ( = 79) collected from food samples were analyzed using concatenated - sequencing. The antibiotic resistance of these isolates was determined using antimicrobial susceptibility testing. Pathogenicity was assessed using β-hemolytic, extracellular protease, virulence gene detection, liquid toxicity (LT), and cytotoxicity assays.

Results: Eight different species were identified among the 79 isolates. The most prevalent species were [62 (78.5%)], [6 (7.6%)], [3 (3.8%)], and [3 (3.8%)]. The isolates were divided into 73 sequence types (STs), of which 65 were novel. The isolates were hemolytic (45.6%) and protease-positive (81.0%). The most prevalent virulence genes were (73.4%), (69.6%), (36.7%), and (30.4%). The results of LT and cytotoxicity assays revealed that and were more virulent than , , and . Antibiotic resistance genes [ , , , , , mcr , and ] were detected in the isolates. The multidrug-resistance rate of the isolates was 11.4%, and 93.7% of the isolates were resistant to cefazolin.

Conclusion: The taxonomy, antibiotic resistance, and pathogenicity of different species varied. The isolates and were highly pathogenic, indicating that food-derived isolates are potential risks for public health and food safety. The monitoring of food quality and safety will result in better prevention and treatment strategies to control diarrhea illnesses in China.