Development and Evaluation of Novel Loop-Mediated Isothermal Amplification for Rapid Detection of blaIMP-1 and blaVIP-2 Genes

Loop-mediated isothermal amplification (LAMP) amplifies a target gene with high specificity and rapidity under isothermal conditions. LAMP assays were developed for the rapid detection of metallo-β-1actamase (MBL) genes such as blaIMP-1 and blaVIM-2. We initially designed specific primers to detect MBL genes for LAMP assays and evaluated the specificity and sensitivity of these assays. LAMP assays amplified MBL genes under a constant temperature of 63°Cwithin 1 hour, and were compared to PCR in MBL-producing strains. The results of MBL genes typing by LAMP assays agree completely with PCR results. The lower detection limits of blaIMP-1-and blaVIM-2-LAMP assays using real-time turbidimeters were 30cfu/test and 3cfu/test, . After amplification, products were directly observed by the naked eye with a fluorescent detection reagent. In conclusion, LAMP assays are convenient, rapid, and fully feasible for detecting MBL genes in ordinary clinical microbiology laboratories without special apparatus.