Loop-Mediated Isothermal Amplification Assay for Identification of Clinical Enterococcus Species

Background: Enterococci are recognized as a cause of nosocomial infections and a major public health problem. The reliable identification to the species level of enterococci should be considered. Objectives: The study aimed to develop a LAMP assay for the rapid and accurate detection of Enterococcus faecalis and E. faecium. Methods: In total, 57 enterococcal isolates from UTI patients were identified using conventional microbiological methods. Two sets of specific primers were designed for E. faecalis and E. faecium targeting the mtlf and efmC genes, respectively. The LAMP assays were conducted using specific primers, dNTPs, MgSO4, Bst DNA polymerase, and templates. Results: The results of phenotypic testing indicated that of the 57 enterococcal isolates, 49 (85.9%) were identified as E. faecalis and eight (14.1%) as E. faecium. The optimal reaction temperatures in the LAMP assays were 60 and 61ºC for the detection of E. faecalis and E. faecium, respectively. All the 57 enterococcal isolates were identified as E. faecalis by the LAMP assay. Conclusions: The present study highlights the importance of the LAMP assay as a rapid and confirmatory tool for the identification of clinical Enterococcus spp.