Tropheryma whipplei - direct diagnosis - PCR
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WHIBM
Synonyms
- Whipple - disease
- Whipple's disease
Specialty
Infectious
Clinical significance
Tropheryma whipplei is a Gram-positive bacillus that cannot be cultivated on standard culture media. The source and mode of transmission are currently poorly understood, but it would appear that this bacterium is transmitted via the fecal-oral and oral-oral routes. Asymptomatic carriage in the faeces affects 4% of the population. There are two clinical forms of T. whipplei infection: classic Whipple's disease and localised infections. Whipple's disease is a rare systemic infection that can affect multiple organs. It affects Caucasian men in particular. Immunosuppression is also a risk factor. Whipple's disease is characterised by positive PAS staining and anti-T. whipplei immunohistochemistry of small intestinal biopsies. The most common form of the disease presents with an altered general condition, arthralgias and digestive signs. PCR in saliva and stools is a very good way of detecting Whipple's disease: a negative PCR in saliva and stools rules out Whipple's disease, while a positive PCR in saliva and/or stools should lead to anatomopathological examination of a duodenal biopsy to confirm the diagnosis. Localised infection with T. whipplei is defined by the absence of a pathological lesion in the digestive tract. A negative PCR on stool or saliva does not rule out a localised infection. PCR must be performed on an appropriate sample: - Endocarditis: PCR on valve biopsy or blood. - Encephalitis or neurological disorders: PCR on cerebrospinal fluid or brain biopsies - Uveitis: PCR on aqueous humour - Adenopathies : PCR on puncture fluid or lymph node biopsies - Arthritis: PCR on joint fluid.
Preanalytics
- Plasma or whole blood (EDTA), serum, saliva, stool, biopsy, BAL, puncture fluids, joint fluids, CSF, urine, aqueous humor
- Reftrigerated
- A tube specifically for this analysis : No
Further information
The use of the S14UK transport bag is Mandatory.
Samples (other than swabs) must be sent as they are, in sterile bottles, without transport medium.
Documents to download
Methodology
Real-time PCR
Turnaround time
3 days