扩增内标在沙门氏菌PCR检测方法中的应用

Application of Internal Amplification Control in the PCR Detection Method for Food-borne Salmonella

在PCR反应体系中添加了一条人工构建的扩增内标片段,以指示沙门氏菌PCR快速检测中出现的假阴性。对9株沙门氏菌和15株非沙门氏菌进行PCR检测,结果显示所有沙门氏菌都能扩增到一条invA基因中的374bp特异性片段,而模板来源于非沙门氏菌时则只能扩增到一条513bp扩增内标片段。灵敏度试验显示,该PCR检测体系对猪霍乱沙门氏菌纯DNA模板的检测灵敏度为12·8fg/μL,如果将增菌时间确定为8h,则该检测体系对人工染菌牛乳中沙门氏菌的检测灵敏度可以达到起始浓度为8cfu/25mL。采用上述方法检测了80份污染严重的样品,证实此方法可以有效地排除假阴性,提高检测准确率。

An intermal amplification control, which could be co-amplified with the invA target gene of Salmonella in the PCR system, was constructed in order to indicate possible PCR inhibitors derived from food samples. Specificity of this PCR system was tested with 9 Salmonella strains and 15 non-Salmonella strains, and the results showed that there was a 374 bp amplicon resulted from all Salmonella strains, while only a 513 bp IAC amplicon appeared after the amplification for all non-Salmonella strains. The detection sensitivity of this PCR system was 12.8 fg/μL for purified target DNA, and the detection limit for artificially inoculated milks was 8 cfu/25g if they wene enriched for 8h in buffered peptone water. Salmonella in 80 samples of seriously contaminated milks was detected by the PCR method developed in this study, and the experiments demonstrated that it could successfully eliminate false-negative nesults.