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

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

Contribution of qPCR in detection of infections of ruminants with Anaplasmataceae: case study in the Basque country and in Corsica

Les Anaplasmataceae sont des bactéries intracellulaires transmises aux animaux et à l’homme, principalement par les tiques. Les Anaplasma spp. (A. marginale, A. phagocytophilum…) et les Ehrlichia spp. (E. canis, E. ruminantium...) en sont les principaux représentants d’importance économique et sanitaire. Les outils de diagnostic disponibles jouent un rôle déterminant dans leur identification. Nous proposons une approche globale par un système permettant d’identifier la plupart des espèces d’Anaplasmataceae. Il est basé sur le gène codant l’ARNr 23S ; il couple une qPCR et une PCR standard avec deux jeux d’amorces suivie d’un séquençage. Il est testé pour en vérifier la spécificité, puis mis en oeuvre à partir de prélèvements de sang de ruminants et de tiques : dans les Pyrénées-Atlantiques, des brebis suspectes d’infection sont porteuses d’A. ovis et leurs tiques Rhipicephalus bursa, d’A. ovis, d’A. phagocytophilum et d’une nouvelle ehrlichia. En Haute-Corse, une forte prévalence d’infections par les Anaplasmataceae est détectée dans des élevages (bovins, ovins, caprins) où la symptomatologie rétrocède lors de traitements à l’oxytétracycline. La spécificité et la sensibilité du système de diagnostic utilisé et sa capacité à identifier de nouvelles espèces offrent des perspectives pour l’étude de l’épidémiologie des Anaplasmataceae et permettront de mettre en évidence de nouveaux réservoirs.The intracelullar bacteria Anaplasmataceae are transmitted by ticks both to animals and to man. The most important species for the economy and for health are Anaplasma spp. (A. marginale, A. phagocytophilum…) and Ehrlichia spp. (E. canis and E. ruminantium...). Whilst current means of diagnosis are indispensible they could be improved. We therefore propose a global approach which will identify most of the species of Anaplasmataceae. It is based on the genetic code ARNr 23S and involves dividing a qPCR into a standard PCR and sequencing. This specificity has been tested, verified and demonstrated in blood samples from ruminants and ticks. Sheep (from Atlantic-Pyrenees) suspected of being infected, were shown to be carriers of A. ovis and their ticks (Rhipicephalus bursa) had A. ovis, A. phagocytophilum and also a new species of ehrlichia. In Corsica, a strong incidence of Anaplasmataceae was detected in the blood of cattle, sheep and goats in which symptoms antedated treatment with oxytetracycline. The specificity and sensibility of this method of diagnosis, as well as its ability to detect new species, are advantageous for further studies of Anaplasmataceae, and facilitate the search for new sources of infection