Table_3_Prevalence, Virulence Feature, Antibiotic Resistance and MLST Typing of Bacillus cereus Isolated From Retail Aquatic Products in China.docx

Bacillus cereus is one of the most important foodborne pathogenic microorganisms, which can lead to gastrointestinal and non-gastrointestinal diseases. However, the potential risk of B. cereus in aquatic products in China has not been comprehensively evaluated yet. In this study, a total of 860 aquatic samples from three types of retail aquatic products were collected from 39 major cities in China from 2011 to 2016. The contamination, distribution of virulence genes, antibiotic resistance and genetic diversity of B. cereus isolates were measured and analyzed. Of all the samples, 219 (25.47%) were positive for B. cereus and 1.83% (4/219) of the samples had contamination levels of more than 1,100 most probable number (MPN)/g. Different isolates had virulence potential, within which 59.6% (164/275) contained all three kinds of enterotoxin genes (nhe, hbl, and cytK-2) and 5.1% (14/275) possessed cereulide encoding gene cesB. The antimicrobial resistance profiles revealed the universal antibiotic resistance to rifampin and most β-lactams, suggesting the necessity to continuously monitor the antibiotic resistance of B. cereus in aquatic products and to control drug use in aquaculture. In sum, our study indicates the potential hazards of B. cereus isolated from aquatic products to customers and may provide a reference for clinical treatment caused by B. cereus.

蜡样芽孢杆菌（Bacillus cereus）是最重要的食源性致病微生物之一，可引发胃肠道与非胃肠道疾病。然而，当前中国水产品中蜡样芽孢杆菌的潜在风险尚未得到全面评估。本研究于2011至2016年间，从中国39个主要城市采集了涵盖3类零售水产品的860份水生样本，对分离得到的蜡样芽孢杆菌的污染情况、毒力基因分布、抗生素耐药性及遗传多样性进行了检测与分析。全部样本中219份（25.47%）蜡样芽孢杆菌检测呈阳性，其中1.83%（4/219）的样本污染水平超过1100最大可能数（most probable number, MPN）/克。各分离株均具备毒力潜力，其中59.6%（164/275）携带全部3种肠毒素基因（nhe、hbl及cytK-2），5.1%（14/275）含有蜡样毒素（cereulide）编码基因cesB。抗菌药物耐药性谱分析结果显示，分离株普遍对利福平（rifampin）及多数β-内酰胺类抗生素存在耐药性，提示需持续监测水产品中蜡样芽孢杆菌的耐药性，并管控水产养殖中的药物使用。综上，本研究证实了从水产品中分离得到的蜡样芽孢杆菌对消费者存在潜在危害，可为蜡样芽孢杆菌引发的临床诊疗提供参考依据。