Department of Botany and Microbiology, Faculty of Science, University of Lagos, Akoka, Lagos, Nigeria.
J Food Prot. 2010 May;73(5):870-8. doi: 10.4315/0362-028x-73.5.870.
The diversity of Bacillus species isolated from the fermented soup condiment okpehe in Nigeria was studied using a combination of phenotypic and genotypic methods. Fifty strains presumptively characterized as Bacillus spp. using the API 50 CHB test were further identified by PCR of randomly amplified polymorphic DNA (RAPD) and by amplified ribosomal DNA restriction analysis (ARDRA) genotyping methods. ARDRA fingerprinting with HhaI, HinfI, and Sau3AI restriction enzymes did not allow successful differentiation between the Bacillus species, except for distinguishing B. cereus from other Bacillus species. This problem was overcome with the combination of RAPD PCR and ARDRA genotypic fingerprinting techniques. Sequencing of 16S rRNA genes of selected strains representative of the major clusters revealed that the Bacillus strains associated with this fermentation were B. subtilis, B. amyloliquefaciens, B. cereus, and B. licheniformis (in decreasing order of incidence). The presence of enterotoxin genes in all B. cereus strains was demonstrated by multiplex PCR. The high incidence of detection (20%) of possibly pathogenic B. cereus strains that contained enterotoxin genes indicated that these fermented foods may constitute a potential health risk.
采用表型和基因型方法相结合，研究了尼日利亚发酵汤调味料 okpehe 中分离出的芽孢杆菌属的多样性。使用 API 50 CHB 测试初步鉴定为芽孢杆菌属的 50 株菌，进一步通过随机扩增多态性 DNA（RAPD）和扩增核糖体 DNA 限制分析（ARDRA）的 PCR 基因分型方法进行鉴定。HhaI、HinfI 和 Sau3AI 限制酶的 ARDRA 指纹图谱分析不能成功区分芽孢杆菌属的不同种，除了能将蜡样芽孢杆菌与其他芽孢杆菌属的种区分开。这一问题通过 RAPD PCR 和 ARDRA 基因指纹图谱分析技术的结合得以解决。对主要聚类中具有代表性的选定菌株的 16S rRNA 基因进行测序，结果表明，与该发酵相关的芽孢杆菌菌株为枯草芽孢杆菌、解淀粉芽孢杆菌、蜡样芽孢杆菌和地衣芽孢杆菌（按发生率降序排列）。通过多重 PCR 证明了所有蜡样芽孢杆菌菌株都存在肠毒素基因。可能致病的含有肠毒素基因的蜡样芽孢杆菌菌株的高检出率（20%）表明，这些发酵食品可能构成潜在的健康风险。
