MOST-USDA Joint Research Center for Food Safety, School of Agriculture & Biology, and State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China.
Foodborne Pathog Dis. 2020 Jan;17(1):35-43. doi: 10.1089/fpd.2019.2671. Epub 2019 Sep 18.
This study characterized the prevalence and antimicrobial resistance characteristics of foodborne isolates from March 2016 to February 2017 in Shanghai, China. A total of 147 (14.2%) nonduplicate foodborne isolates were obtained from 1035 food samples. The isolates were most frequently identified in fresh meat samples (28.0%), followed by ready-to-eat foods (9.0%), frozen convenience foods (7.1%), and fresh produce (4.5%). The top 3 serovars were Enteritidis (46.3%; 68/147), Typhimurium (32.7%; 48/147), and Derby (6.8%; 10/147). The majority of isolates were resistant to sulfisoxazole (93.9%; 138/147) and trimethoprim/sulfamethoxazole (61.2%; 90/147). Interestingly, frozen convenience food isolates exhibited an extremely high multidrug resistance rate (86.7%; resistant to ≥3 classes of antimicrobials). Among 81 quinolone-resistant isolates, (100%), AB (84.0%), S1 (23.5%), D87Y (49.4%), and D87N (33.3%) mutations in GyrA, and T57S in ParC (12.3%) were observed. The β-lactamase genes (100%) were present in 63 ampicillin-resistant isolates. Polymerase chain reaction-based plasmid replicon typing revealed that 147 isolates represented 6 plasmid incompatibility groups (IncFIIs, IncHI2, IncI1, IncP, IncFIC, and IncA/C), among which, IncFIIs (59.2%) and IncHI2 (26.5%) were predominant. The genetic relationship of isolates was elucidated using multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). MLST results indicated that ST34 and ST11 were predominate types in Typhimurium (56.3%; 27/48) and Enteritidis (95.6%; 65/68), respectively. Importantly, 96.3% (26/27) of ST34 Typhimurium isolates possessed the ACSSuT resistance pattern (ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline). PFGE analysis of ST34 isolates showed clonal dissemination across all four types of retail foods. Our findings highlight the high prevalence of antimicrobial-resistant isolates in retail foods in Shanghai, especially the clonal expansion of ST34 isolates with MDR-ACSSuT resistance, which might pose a public health threat.
本研究旨在描述 2016 年 3 月至 2017 年 2 月期间中国上海食源性 分离株的流行情况和耐药特征。从 1035 份食品样本中获得了 147 株（14.2%）非重复食源性 分离株。分离株最常从新鲜肉样本中鉴定出来（28.0%），其次是即食食品（9.0%）、冷冻方便食品（7.1%）和新鲜农产品（4.5%）。排名前三的血清型分别是肠炎沙门氏菌（46.3%，68/147）、鼠伤寒沙门氏菌（32.7%，48/147）和德比沙门氏菌（6.8%，10/147）。大多数分离株对磺胺异噁唑（93.9%，138/147）和甲氧苄啶/磺胺甲噁唑（61.2%，90/147）耐药。有趣的是，冷冻方便食品分离株表现出极高的多药耐药率（86.7%，对≥3类抗菌药物耐药）。在 81 株耐喹诺酮类药物的分离株中，gyrA 中的 D87Y（49.4%）和 D87N（33.3%）突变、AB（84.0%）、S1（23.5%）和 parC 中的 T57S（12.3%）均观察到。在 63 株氨苄西林耐药分离株中均存在 blaCTX-M-15 基因（100%）。基于聚合酶链反应的质粒复制子分型显示，147 株分离株代表了 6 种质粒不相容群（IncFIIs、IncHI2、IncI1、IncP、IncFIC 和 IncA/C），其中 IncFIIs（59.2%）和 IncHI2（26.5%）占优势。多位点序列分型（MLST）和脉冲场凝胶电泳（PFGE）结果表明，ST34 和 ST11 分别是鼠伤寒沙门氏菌（56.3%，27/48）和肠炎沙门氏菌（95.6%，65/68）中的主要型别。重要的是，96.3%（26/27）的 ST34 鼠伤寒沙门氏菌分离株具有 ACSSuT 耐药模式（氨苄西林、氯霉素、链霉素、磺胺甲噁唑和四环素）。ST34 分离株的 PFGE 分析显示，所有四种零售食品均存在克隆传播。我们的研究结果强调了上海零售食品中存在高比例的耐药 分离株，特别是具有 MDR-ACSSuT 耐药性的 ST34 分离株的克隆扩张，这可能对公共卫生构成威胁。
