whipplei causes Whipple disease, a rare multisystemic disorder that affects mainly middle-aged white men and is most widely distributedin Europe and North America (1). In the general population of France, T. whipplei DNA was found in 2%–4% of stool samples and T. whipplei– specific antibodies were found in 51 % of serum samples (2). Still, the prevalence of classic Whipple disease, which causes arthralgia, diarrhea, and weight loss, remains extremely low (1). Whipple disease has 4 known manifestations: 1) classic Whipple disease; 2) focused chronic infections, mainly endocarditis; 3) acute infections, such as gastroenteritis, bacteremia, and pneumonia; and 4) asymptomatic T. whipplei carriage in healthy persons (1–5). T. whipplei is thought to be transmitted through oral and oro–fecal routes by human-tohuman contact (2,6). The pathogen was cultivated in 2000, and 2 genomes were sequenced (reference strains Twist and TW08/27) (7,8). These events made possible a genotyping system based on 4 highly variable genetic sequences found by genome comparison (TW133, ProS, SecA, Pro184) (9). Since 2007, we have applied this system to patient samples positive for T. whipplei from central Europe and sub-Saharan Africa (2,3,9,10). The system showed a higher discriminatory power than previous typing methods and improved the genotyping resolution of T. whipplei, promoting better understanding of its epidemiology on the molecular level (9). Since 2003, we have subcultured strain Twist every 3 weeks. In 2007 and 2012, we compared sequences for the subcultured strains with that for the 2003 strain. We found that the spacer sequence remained stable over the ≈10-year period. This finding suggests a high intrastrain genetic stability and highlights the value of the typing system, which is stable. Thus, a change in genotype in a patient with Whipple disease must be interpreted as an infection with a different strain and cannot be attributed to mutation of the original strain. To date, 191 samples positive for T. whipplei collected from patients from central Europe (France, Germany, Switzerland, Austria, and Italy) have been typed, revealing a genetic diversity by identifying 72 differen
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