Prevalence and detection of Tropheryma whipplei in the stools of Korean patients with diarrhea using real-time PCRs

BACKGROUND: The prevalence of Tropheryma whipplei varies depending on age, region, and underlying disease. We estimated the prevalence of T. whipplei in the stools of Korean patients with diarrhea using real-time PCR (RT-PCR) and compared three RT-PCR targets, rpoB, hsp65, and Dig15. METHODS: A total of 1404 nucleic acid samples extracted from the stools of Korean patients with diarrhea were tested using an initial RT-PCR targeting T. whipplei-specific regions of 16S–23S rRNA intergenic spacer. Subsequently, the samples positive for the initial RT-PCR were tested using the follow-up RT-PCRs targeting rpoB, hsp65, and Dig15 and analyzed by sequencing to confirm the presence of T. whipplei. We estimated the prevalence of T. whipplei and compared them according to gender and age. We also compared the performance of three targets in the follow-up RT-PCRs. RESULTS: T. whipplei was detected in 1.4% of all samples (20 of 1404), and there were no differences according to gender and age. In pediatric samples (≤ 19 years), T. whipplei was detected higher in children aged 6–19 than in those aged 1–5 (2.7% vs. 0.7%, P = 0.01). Sensitivities of the rpoB, hsp65, and Dig15 RT-PCR were 50.0%, 85.0%, and 95.0%, respectively; specificities were 100.0%, 100.0%, and 84.6%, respectively. CONCLUSIONS: This is the first study that estimated the prevalence of T. whipplei in the stools of Korean patients with diarrhea. This study demonstrated the presence of T. whipplei in stools of Koreans, even though the bacterium was detected low. The RT-PCRs targeting hsp65 and Dig15 showed reliable performance, and a multiplex PCR including these targets is expected to be useful for T. whipplei detection.