Division of Microbiology, Defence Food Research Laboratory, Siddhartha Nagar, Mysore, 570 011 India.
Indian J Microbiol. 2009 Sep;49(3):283-9. doi: 10.1007/s12088-009-0032-y. Epub 2009 Jun 5.
Three important foodborne pathogens, Bacillus cereus, Listeria monocytogenes and Staphylococcus aureus are of major concern for food safety in terms of frequency and seriousness of the disease. The occurrence these three important pathogens and their coexistence in food matrices are predominant. Moreover, symptoms associated with B. cereus and S. aureus food poisoning not only closely resembles each other but can also be overlapping with other foodborne infections. In this context, detection of these three pathogens simultaneously in food samples by a single multiplex PCR (mPCR) would have advantages in terms of rapidity and cost saving, when compared with single organism specific PCRs. mPCR has been standardized by targeting three major diarrheal enterotoxin genes hbl A, cyt K and nhe A of B. cereus, virulence associated nuc and Ent B genes of S. aureus and virulence associated hly and iap genes of L. monocytogenes along with internal amplification control (IAC). The results showed that mPCR accurately identified all the three organisms individually or in combination without non-specificity. The mPCR was able to detect as low as 10 to 100 organisms per ml of growth following overnight enrichment of spiked food samples (vegetable biriyani and milk) and their presence in naturally contaminated samples also. The high throughput and cost effective multiplex PCR method developed in this study could provide a powerful tool for simultaneous, rapid and reliable detection of B. cereus, S. aureus and L. monocytogenes in food samples.
三种重要的食源性致病菌，蜡样芽孢杆菌、单增李斯特菌和金黄色葡萄球菌，在疾病的频率和严重程度方面是食品安全的主要关注点。这些三种重要病原体的发生及其在食品基质中的共存是主要的。此外，与蜡样芽孢杆菌和金黄色葡萄球菌食物中毒相关的症状不仅彼此相似，而且还可能与其他食源性感染重叠。在这种情况下，与单一生物体特异性 PCR 相比，通过单个多重 PCR（mPCR）同时检测食品样品中的这三种病原体在快速性和节省成本方面具有优势。mPCR 已通过针对蜡样芽孢杆菌的三个主要腹泻肠毒素基因 hbl A、cyt K 和 nhe A、金黄色葡萄球菌的毒力相关 nuc 和 Ent B 基因以及内部扩增对照（IAC）进行了标准化。结果表明，mPCR 能够准确地单独或组合识别所有三种生物体，而没有非特异性。mPCR 能够在过夜富集添加的食物样品（蔬菜 biriyani 和牛奶）后检测到低至 10 到 100 个生物体/ml 的生长，并且在自然污染的样品中也存在。本研究开发的高通量、成本效益高的多重 PCR 方法可以为同时、快速和可靠地检测食品样品中的蜡样芽孢杆菌、金黄色葡萄球菌和单增李斯特菌提供一种强大的工具。
