Abstract：
Pre-cut fresh fruits and vegetables are highly appealing to consumers for their convenience, however, as they are highly susceptible to microbial contamination in processing, the potential risks of foodborne illnesses to public health are not negligible. This study aimed to assess the prevalence, antibiotic susceptibility and molecular characteristics of major foodborne pathogens (Listeria monocytogenes, Escherichia coli, Staphylococcus aureus and Salmonella) isolated from fresh-cut fruits and vegetables in Beijing, China. 86 stains were isolated from 326 samples, with S. aureus being the highest prevalence (15.38 %), followed by E. coli (9.23 %) and L. monocytogenes (1.85 %), while no Salmonella was detected. The prevalence by type of food indicated that fruit trays and mixed vegetables were more susceptible to contamination by pathogens. 98 % of S. aureus were resistant to at least of one antibiotic, and showed a high resistance rate to benzylpenicillin (90 %) and oxacillin (48 %). Among 25 E. coli isolates, 57.67 % of which exhibited multi-drug resistance, with common resist to trimethoprim/sulfamethoxazole (66.67 %) and ampicillin (63.33 %). A total of 9 sequence types (STs) and 8 spa types were identified in 35 S. aureus isolates, with ST398-t34 being the predominant type (42.86 %). Additionally, analysis of 25 E. coli isolates demonstrated significant heterogeneity, characterized by 22 serotypes and 18 STs. Genomic analysis revealed that 5 and 44 distinct antibiotic resistance genes (ARGs) in S. aureus and E. coli, respectively. Seven quinolone resistance-determining regions (QRDRs) mutations were identified in E. coli isolates, of which GyrA (S83L) was the most frequently detected. All the S. aureus and E. coli isolates harbored virulence genes. ARGs in S. aureus and E. coli showed a significant positive correlation with plasmids. Furthermore, one L. monocytogenes isolate, which was ST101 and serogroupIIc from watermelon sample, harbored virulence genes (inlA and inlB) and LIPI-1 pathogenic islands (prfA, plcA, hly and actA), which posed potential risks for consumer\'s health. This study focused on the potential microbial risk of fresh-cut fruits and vegetables associated with foodborne diseases, improving the scientific understanding towards risk assessment related to ready-to-eat foods.
摘要：
预切的新鲜水果和蔬菜因其方便而高度吸引消费者，然而,因为它们在加工过程中极易受到微生物污染，食源性疾病对公众健康的潜在风险不容忽视。这项研究旨在评估患病率，主要食源性病原体的抗生素敏感性和分子特征(单核细胞增生李斯特菌，大肠杆菌,金黄色葡萄球菌和沙门氏菌）从北京鲜切水果和蔬菜中分离，中国。从326个样品中分离出86个污渍，金黄色葡萄球菌患病率最高(15.38%)，其次是大肠杆菌(9.23%)和单核细胞增生李斯特菌(1.85%)，而没有检测到沙门氏菌。食物类型的流行表明，果盘和混合蔬菜更容易受到病原体的污染。98%的金黄色葡萄球菌对至少一种抗生素具有抗性，对青霉素(90%)和苯唑西林(48%)的耐药率较高。在25个大肠杆菌分离物中,其中57.67%呈现多药耐药,与甲氧苄啶/磺胺甲恶唑（66.67%）和氨苄西林（63.33%）共同耐药。在35株金黄色葡萄球菌中鉴定出9种序列类型(STs)和8种spa类型,以ST398-T34为主(42.86%)。此外,对25个大肠杆菌分离株的分析显示出显著的异质性，以22种血清型和18种STs为特征。基因组分析显示，金黄色葡萄球菌和大肠杆菌中存在5个和44个不同的抗生素抗性基因(ARGs)，分别。在大肠杆菌分离株中鉴定出7个喹诺酮耐药决定区（QRDR）突变，其中GyrA（S83L）是最常见的检测。所有金黄色葡萄球菌和大肠杆菌分离物都具有毒力基因。金黄色葡萄球菌和大肠杆菌中的ARGs与质粒呈显著正相关。此外，一种单增李斯特菌分离物，来自西瓜样本的ST101和血清群IIc，携带毒力基因(inlA和inlB)和LIPI-1致病岛(prfA，plcA,hly和acta)，这对消费者的健康构成了潜在的风险。这项研究的重点是与食源性疾病相关的鲜切水果和蔬菜的潜在微生物风险，提高对即食食品风险评估的科学认识。
