쯔쯔가무시병 진단에 있어서 16S ribosomal RNA 유전자를 이용한 실시간 중합효소 연쇄반응 검사의 임상적 유용성

Abstract

Scrub typhus is a major acute febrile disease in Asia-pacific region caused by Orientia tsutsugamushi. Delays in diagnosis can cause fatal complications, so a rapid and early diagnosis is indispensable for successful treatment. For this reason, a polymerase chain reaction (PCR) based method was developed to detect a specific O. tsutsugamushi gene in a patient`s blood. Real-time PCR(Q-PCR) has the advantages of high speed, sensitivity, suggesting the utility of this technique for the early diagnosis of scrub typhus. We evaluated the clinical usefulness of the real-time quantitative polymerase chain reaction (Q-PCR) targeting of 16S ribosomal RNA (16S rRNA) gene. We examined blood specimens from 148 adult patients confirmed to have scrub typhus from September 2008 to December 2009. Among 148 scrub typhus patients, Before admission, 36 patients were treated by antibiotics, and 112 patients were not treated by antibiotics. To evaluate the clinical usefulness of 16S rRNA Q-PCR, we compared its diagnostic accuracy to that of the following methods: nested PCR(N-PCR) targeting the 56-kDa gene, Q-PCR targeting the 47-kDa gene, and conventional PCR(C-PCR) targeting 16S rRNA gene. 16S rRNA Q-PCR detected O. tsutsugamushi infection with a sensitivity of 91.9%, and 56-kDa N-PCR, 47-kDa Q-PCR, 16s rRNA C-PCR showed lower sensitivities of 81.1%, 74.3%, and 87.8% in all 148 patients. And 16S rRNA Q-PCR showed a sensitivity of 99.1% in 112 patients without antibotics treatment before admission. In conclusion, 16S rRNA Q-PCR is clinically useful for rapid diagnosis of scrub typhus and more accurate than 56-kDa N-PCR, 47-kDa Q-PCR, and 16S C-PCR.