Медицинская микробиология и диагностика

Loop-Mediated Isothermal Amplification Assay Targeting the 47-Kda Gene of Orientia tsutsugamushi: A Rapid and Sensitive Alternative to Real-Time PCR

Abstract

Erin Huber, Darder Ji, Lee Howell, Zhiwen Zhang, Hua-Wei Chen, Wei-Mei Ching, Chien-Chung Chao

A sensitive, specific and rapid diagnostic test for the detection of Orientia tsutsugamushi, the causative agent of scrub typhus, is necessary to accurately and promptly diagnose patients and ensure that they receive proper treatment. A Loop-Mediated Isothermal Amplification (LAMP) assay targeting the 47-kDa gene of tsutsugamushi was developed. The LAMP assay was capable of detecting eleven different strains of Orientia at levels comparable to that of the quantitative PCR based method of detection. Ten patient specimens, confirmed to be positive for Orientia by two different PCR methods, were tested and nine out of ten were determined to be positive by LAMP. In terms of specificity, the assay was able to differentiate between Orientia and other phylogenetically similar bacteria as well as mouse and human host DNA. In addition to being sensitive and specific, the LAMP reaction was completed in 1 hour, demonstrating that it is a highly time-efficient method of diagnosing scrub typhus.