False positive PCR detection of Tropheryma whipplei in the saliva of healthy people

<p>Abstract</p> <p>Background</p> <p><it>Tropheryma whipplei</it>, the agent of Whipple's disease (WD), has been recently isolated and the genomes of two isolates have been fully sequenced. Previous diagnosis tools for the diagnosis of the disease used sequence analysis of the 16S rRNA gene. Using this target gene, the high percentage of detection of the bacterium in saliva of healthy people was in contrast to the negative results obtained with specific target genes. The aim of our study was to compare previously published primers targeting the 16S rRNA gene to real-time PCR with Taqman* probes targeting specific repeat genes only found in the genome of <it>T. whipplei </it>in a series of 57 saliva from healthy people.</p> <p>Results</p> <p>Although the specific real-time PCR assays with both primers and probes were negative for all the samples, 13 out of 57 samples were positive with different primers previously reported targeting the 16S rRNA gene. Among the positive samples, 8 yielded a 231-bp sequence that was 99.1% identical to that of <it>Actinomyces odontolyticus</it>, 2 yielded a 226-bp that was 99.6% identical to that of <it>A. turicensis</it>, and 3 yielded a 160-bp sequence that was 98.5% identical to that of <it>Capnocytophaga gingivalis</it>. We found that the <it>C. gingivalis </it>and <it>A. odontolyticus </it>16S rRNA sequences obtained in our study share more than 80% homology with the corresponding 16S rRNA sequences of the <it>T. whipplei </it>genomes especially at 5' and 3' end.</p> <p>Conclusion</p> <p>Asymptomatic carriers of <it>T. whipplei </it>in saliva may exist but their prevalence is much lower than those previously reported. Testing the specificity of designed primers is critical to avoid false positive detection of <it>T. whipplei</it>. In atypical case we recommend to test two different specific target genes before concluding.</p

Tropheryma whipplei in Fecal Samples from Children, Senegal

We tested fecal samples from 150 healthy children 2–10 years of age who lived in rural Senegal and found the prevalence of Tropheryma whipplei was 44%. Unique genotypes were associated with this bacterium. Our findings suggest that T. whipplei is emerging as a highly prevalent pathogen in sub-Saharan Africa

Increased Levels of Circulating IL-16 and Apoptosis Markers Are Related to the Activity of Whipple's Disease

BACKGROUND: Whipple's disease (WD) is an infectious disease caused by Tropheryma whipplei, which replicates in macrophages and induces the release of interleukin (IL)-16, a substrate of caspase 3, and macrophage apoptosis. The disease is characterized by intestinal, cardiac or neurological manifestations; its diagnosis is based on invasive analysis requiring tissue biopsies or cerebrospinal fluid puncture. The disease progression is slow and often complicated by relapses despite empirical antibiotic treatment. METHODOLOGY/PRINCIPAL FINDINGS: We monitored circulating levels of IL-16 and nucleosomes in 36 French patients with WD; among them, some patients were enrolled in a longitudinal follow-up. As compared to control subjects, the circulating levels of both IL-16 and nucleosomes were increased in untreated patients with WD presenting as intestinal, cardiac or neurological manifestations. This finding was specific to WD since the circulating levels of IL-16 and nucleosomes were not increased in patients with unrelated inflammatory diseases such as inflammatory bowel disease or Q fever endocarditis. We also found that increased levels of IL-16 and nucleosomes were related to the activity of the disease. Indeed, successful antibiotic treatment decreased those levels down to those of control subjects. In contrast, patients who suffered from relapses exhibited circulating levels of IL-16 and nucleosomes as high as those of untreated patients. CONCLUSIONS/SIGNIFICANCE: Circulating levels of both IL-16 and nucleosomes were increased in WD. This finding provides simple and non-invasive tools for the diagnosis and the prognosis of WD

Tropheryma whipplei in Children with Gastroenteritis

This bacterium may be an etiologic agent of gastroenteritis

Fatal myocarditis-associated Bartonella quintana endocarditis: a case report

<p>Abstract</p> <p>Introduction</p> <p><it>Bartonella</it> spp. infection is not rare and must be considered with great care in patients with suspected infective endocarditis, particularly if regular blood cultures remain sterile. Management of these infections requires knowledge of the identification and treatment of these bacteria.</p> <p>Case presentation</p> <p>A 50-year-old Senegalese man was admitted to our Department of Cardiac Surgery with a culture-negative endocarditis. Despite valvular surgery and adequate antibiotic treatment, recurrence of the endocarditis was observed on the prosthetic mitral valve. Heart failure required circulatory support. Weaning off the circulatory support could not be attempted owing to the absence of heart recovery. Bacteriological diagnosis of <it>Bartonella quintana</it> endocarditis was performed by molecular methods retrospectively after the death of the patient.</p> <p>Conclusions</p> <p>This case report underlines the severity and difficulty of the diagnosis of <it>Bartonella quintana</it> endocarditis. The clinical picture suggested possible <it>Bartonella quintana</it> associated myocarditis, a feature that should be considered in new cases.</p

Tropheryma whipplei in Patients with Pneumonia

This bacterium may be an etiologic agent of pneumonia

Progressive dementia associated with ataxia or obesity in patients with Tropheryma whipplei encephalitis

<p>Abstract</p> <p>Background</p> <p><it>Tropheryma whipplei</it>, the agent of Whipple's disease, causes localised infections in the absence of histological digestive involvement. Our objective is to describe <it>T. whipplei </it>encephalitis.</p> <p>Methods</p> <p>We first diagnosed a patient presenting dementia and obesity whose brain biopsy and cerebrospinal fluid specimens contained <it>T. whipplei </it>DNA and who responded dramatically to antibiotic treatment. We subsequently tested cerebrospinal fluid specimens and brain biopsies sent to our laboratory using <it>T. whipplei </it>PCR assays. PAS-staining and <it>T. whipplei </it>immunohistochemistry were also performed on brain biopsies. Analysis was conducted for 824 cerebrospinal fluid specimens and 16 brain biopsies.</p> <p>Results</p> <p>We diagnosed seven patients with <it>T. whipplei </it>encephalitis who demonstrated no digestive involvement. Detailed clinical histories were available for 5 of them. Regular PCR that targeted a monocopy sequence, PAS-staining and immunohistochemistry were negative; however, several highly sensitive and specific PCR assays targeting a repeated sequence were positive. Cognitive impairments and ataxia were the most common neurologic manifestations. Weight gain was paradoxically observed for 2 patients. The patients' responses to the antibiotic treatment were dramatic and included weight loss in the obese patients.</p> <p>Conclusions</p> <p>We describe a new clinical condition in patients with dementia and obesity or ataxia linked to <it>T. whipplei </it>that may be cured with antibiotics.</p