Short Report: Detection of Orientia Tsutsugamushi in Clinical Samples by Quantitative Real-Time Polymerase Chain Reaction

摘要

Orientia tsutsugamushi infection causes scrub typhus, a common zoonosis of rural Asia. Orientia tsutsugamushi was recently detected by a real- time quantitative polymerase chain reaction (qPCR) assay in animal specimens. We evaluated the same qPCR assay in specimens obtained from patients with serologically proven scrub typhus infections. The 47-kDa qPCR assay was more sensitive than was mouse inoculation; it was reactive in whole blood specimens from all 10 isolate-positive patients and in 7 of 17 isolate-negative individuals (P= 0.003, Fisher's two-tailed exact test). As few as 1,076 O. tsutsugamushi copies/microLiter were detected in whole blood. Four of 7 sera from isolate-proven scrub typhus infections were also reactive by qPCR. The assay was unreactive in all 12 individuals without scrub typhus infection. This is the first demonstration of a sensitive and specific real-time qPCR assay for human scrub typhus infection.