Abstract:

For visual detection of the disinfection effect of disinfectant products, a new method combining propidium monoazide （PMA, a dye） with loop-mediated isothermal amplification （LAMP） was established. Five commercial disinfection products with different ingredients were randomly selected in this research. Glass slides covered with bacteria were freshly prepared before use. After disinfection treatment by the disinfection products, the bacteria solutions were collected and then treated with PMA separately. Bacterial genomic DNA was extracted from the bacterial solutions. Subsequently, gDNA was used as template for LAMP and real-time PCR for amplification of fecA gene of Escherichia coli and 16S rRNA which universally existed in bacteria. Meanwhile, by adding calcein to the reaction system, the disinfection effect could be determined. The color change from fluorescent green to light orange in reaction tube could be observed by naked eyes. Excluding the step of disinfection treatment, the detection procedure could be completed within 45 min. Compared with PMA-qPCR, PMA-LAMP had the advantages of easy to operate, more sensitive, faster in detection, and no need of precise temperature-controlling instruments. For testing the disinfection effects of actual disinfection products, the results of PMA-LAMP were basically consistent with those of the standard method （refer to Technical Standard for Disinfection （2002 edition））, with a deviation within±0.5 between the two methods. The newly established PMA-LAMP method had good application prospect in field experiments. It would provide technical support for performance evaluation of disinfection products and market supervision.

Key words: propidium monoazide, loop-mediated isothermal amplification, visual detection, disinfection product, disinfection effect