中文摘要：

建立一种将荧光染料叠氮溴化丙锭（propidium monoazide,PMA）与环介导等温扩增（loop-mediated isothermal amplification,LAMP）技术相结合的方法,用于快速高效检测金黄色葡萄球菌（Staphylococcus aureus）。同时,采用人工污染金黄色葡萄球菌的速冻水饺和奶粉作为食品样品,研究PMA-LAMP方法的检测灵敏度。结果表明,PMA溶液质量浓度3μg/mL,650 W卤素灯下曝光5 min,PMA能够完全抑制1.2×10^7 copies/mL金黄色葡萄球菌死菌核酸扩增。PMA-LAMP方法能够在恒温65℃、60 min内完成对亚致死型金黄色葡萄球菌特异性nuc基因的特异性检测,其对亚致死状态金黄色葡萄球菌的检出限为34 CFU/mL,对食物样品速冻水饺和奶粉的检出限分别为17 CFU/m L和1.70×10^2 CFU/mL。建立的PMA-LAMP方法可以有效检测亚致死态金黄色葡萄球菌,提供了一种新的检测技术和解决方案。

英文摘要：

In this study,a loop-mediated isothermal amplification（LAMP） assay combined with propidium monoazide（PMA） treatment was developed for the rapid and efficient detection of Staphylococcus aureus with sublethal injury.The sensitivity of PMA-LAMP was investigated by artificially contaminating food samples including frozen dumplings and milk powder with S.aureus.The results showed that a concentration of 3 μg/mL PMA was optimal for completely restraining the amplification of 1.2 ×10^7 copies/mL of DNA from dead S.aureus which was exposed to a 650 W halogen lamp for 5 min.PMA-LAMP could achieve the specific detection of the unique nuc gene of S.aureus with sublethal injury at a constant temperature of 65 ℃ within 60 min with a sensitivity of 34 CFU/mL.In addition,the PMA-LAMP assay was proved efficient by using it to detect the viable cells in artificially contaminated samples,with a sensitivity of 17 CFU/mL for artificially contaminated milk powder and 1.70 × 10^2 CFU/mL in artificially contaminated frozen dumplings.It can be concluded that the PMA-LAMP assay can efficiently detect S.aureus with sublethal injury and provide a new technique for detecting S.aureus in food samples.