Description of Tropheryma whipplei gen. nov., sp nov., the Whipple's disease bacillus

A detailed characterization was performed of the Whipple's disease bacillus , strain Twist-Marseille(T), isolated from the cardiac valve of a patient w ith Whipple's disease bacillus endocarditis, This strain was isolated and m aintained on human embryonic lung fibroblast monolayers, but could not be c ultivated in the absence of living eukaryotic cells. Two morphological form s were observed, with differing staining properties; an intracellular form with intact and degenerating bacteria within vacuoles of infected cells and an extracellular form with masses of bacteria embedded in an extracellular matrix. Determination of the DNA G+C content confirmed that it belongs to the high-G+C Gram-positive bacteria, Strain Twist-Marseille(T) (= CNCM I-22 02(T)) is proposed as the type strain of a new species within a new genus, Tropheryma whipplei gen, nov., sp. nov., that was provisionally created sol ely on the basis of 16S rRNA gene sequence data.