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BACKGROUND: DNA of Tropheryma whipplei, the etiologic agent of Whipple's disease, has recently been detected in the saliva of healthy subjects. In this pilot study we searched for the habitat of T. whipplei within the oral cavity. MATERIALS AND METHODS: Samples from different oral sites were obtained from periodontically healthy volunteers, patients with progressive periodontitis and Chinese subjects with necrotizing ulcerative gingivitis or gingivitis. Quantitative real-time PCR was performed using T. whippleispecific primers, human beta-globin-specific primers to control for tissue DNA extraction and PCR reaction and broad-range eubacterial primers to control for bacterial DNA extraction. T. whipplei specificity of multiple amplicons was confirmed by sequencing. The detection limit of the method was 10 ag of T. whipplei DNA, corresponding to one to five bacteria under reference assay conditions. RESULTS: T. whipplei was found in the oral cavity of four out of ten healthy individuals from hospital staff and in three out of nine periodontitis patients, but in none of the individuals from China. All positive samples derived from subgingival and gingival sulcus plaque containing between 10(3) and 5 x 10(5) cells ml(-1) of plaque suspension, whereas saliva, smooth surface plaque and samples from the tongue or cheeks were negative. CONCLUSION: Our results suggest that T. whipplei colonizes the human body via the oral cavity and that bacterial plaques of the gingival crevice and the gingival sulcus/pocket may serve as a natural primary habitat.

In the study presented here a LightCycler real-time PCR system was used for the diagnosis of fungal infections from clinical tissue samples. Nine specimens were investigated from six patients with suspected or proven invasive fungal infections. Seven of nine samples were positive in a broad-range fungal PCR assay. In four samples, Aspergillus fumigatus was detected both by a species-specific hybridization assay as well as by sequencing of amplification products. In addition, the broad-range fungal PCR assay and PCR sequencing detected and identified, respectively, the following organisms in the specimens noted: Candida albicans in a culture-negative liver biopsy, Histoplasma capsulatum in a bone marrow sample, and Conidiobolus coronatus in a facial soft tissue specimen. Real-time PCR is a promising tool for the diagnosis of invasive fungal infections in human tissue samples and offers some advantages over culture methods, such as rapid analysis and increased sensitivity.