Assessment and molecular characterization of Bacillus cereus isolated from edible fungi in China

BMC Microbiology

article

Liu, Chengcheng¹  Wu, Shi¹  Gu, Qihui¹  Zeng, Haiyan¹  Zhang, Youxiong¹  Wei, Xianhu¹  Zhang, Jumei¹  Wu, Qingping¹  Ding, Yu¹  Yu, Pengfei¹  Yu, Shubo¹  Wang, Juan³  Guo, Hui¹  Zhang, Ying¹  Zhang, Junhui¹  Liao, Xiyu¹  Li, Chun² 

[1] Guangdong Institute of Microbiology, Guangdong Academy of Science, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Safety and Health, Guangdong Open Laboratory of Applied Microbiology;Department of Food Science and Technology, Institute of Food Safety and Nutrition, Jinan University;College of Food Science, South China Agricultural University

关键词: Bacillus cereus;    Edible fungi;    Prevalence;    Antibiotic resistance;    Genetic diversity;   

DOI  :  10.1186/s12866-020-01996-0

学科分类：放射科、核医学、医学影像

来源: BioMed Central

【 摘 要 】

Bacillus cereus is a foodborne pathogen commonly found in nature and food and can cause food spoilage and health issues. Although the prevalence of B. cereus in foods has been reported worldwide, the extent of contamination in edible fungi, which has become increasingly popular as traditional or functional food, is largely unknown. Here we investigated the prevalence, toxin genes’ distribution, antibiotic resistance, and genetic diversity of B. cereus isolated from edible fungi in China. Six hundred and ninety-nine edible fungi samples were collected across China, with 198 (28.3%) samples found to be contaminated by B. cereus, with an average contamination level of 55.4 most probable number (MPN)/g. Two hundred and forty-seven B. cereus strains were isolated from the contaminated samples. Seven enterotoxin genes and one cereulide synthetase gene were detected. The detection frequencies of all enterotoxin genes were ≥ 80%, whereas the positive rate of the cesB gene in B. cereus was 3%. Most isolates were resistant to penicillins, β-lactam/β-lactamase inhibitor combinations, cephems, and ansamycins, but were susceptible to penems, aminoglycosides, macrolides, ketolide, glycopeptides, quinolones, phenylpropanol, tetracyclines, lincosamides, streptogramins, and nitrofurans. Meanwhile, 99.6% of all isolates displayed multiple antimicrobial resistance to three or more classes of antimicrobials. Using genetic diversity analysis, all isolates were defined in 171 sequence types (STs), of which 83 isolates were assigned to 78 new STs. This study provides large-scale insight into the prevalence and potential risk of B. cereus in edible fungi in China. Approximately one-third of the samples were contaminated with B. cereus, and almost all isolates showed multiple antimicrobial resistance. Detection frequencies of all seven enterotoxin genes were equal to or more than 80%. These new findings may indicate a need for proper pre-/post-processing of edible fungi to eliminate B. cereus, thereby preventing the potential risk to public health.

【 授权许可】

CC BY|CC0