쯔쯔가무시병 진단에서 등온증폭법과 중합효소 연쇄반응의 비교분석

Abstract

The causative agent of scrub typhus is Orientia tsutsugamushi, and is transmitted by the bite of an infected chigger. It is the representative acute febrile disease shown up for the autumn season in Korea. It shows good response to antibiotic therapy. However when diagnosis is delayed serious complications such as pneumonia, acute renal failure, encephalitis, upper gastrointestinal bleeding, and death may develop. Rapid and accurate diagnosis for appropriate treatment is required. Loop-mediated Isothermal Amplification Assay (LAMP) and Polymerase Chain Reaction (PCR) were compared to detect against a 47 kDa protein gene of O. tsutsugamushi for the diagnosis of scrub typhus. In this study, we used the specimens of 72 adult patients aged 18 years or older who visited Chosun University Hospital between September 2006 and December 2008 within 4 weeks of fever onset. Scrub typhus was confirmed as a four-fold greater increase in antibody titers or Ig M antibody greater than 1:10 measured by Indirect Immunofluorescence Assay The LAMP assay had a sensitivity of 17.31% (n = 9) and Q-PCR of 73.08% (n = 38) out of 52 positive samples. The LAMP assay performed withhout Loop-primers showed a sensitivity of 61.54%. Both LAMP and PCR assays evaluated were 100% specific for O. tsutsugamushi. In conclusion, the LAMP assays targetting a 47 kDa protein gene of O. tsutsugamushi are not more sensitive than Q-PCR for the diagnosis of scrub typhus, even though it is more simple and easier to achieve.