Development of a duplex real-time PCR for the detection of Rickettsia spp. and typhus group rickettsia in clinical samples.

Molecular diagnosis using real-time polymerase chain reaction (PCR) may allow earlier diagnosis of rickettsiosis. We developed a duplex real-time PCR that amplifies (1) DNA of any rickettsial species and (2) DNA of both typhus group rickettsia, that is, Rickettsia prowazekii and Rickettsia typhi. Primers and probes were selected to amplify a segment of the 16S rRNA gene of Rickettsia spp. for the pan-rickettsial PCR and the citrate synthase gene (gltA) for the typhus group rickettsia PCR. Analytical sensitivity was 10 copies of control plasmid DNA per reaction. No cross-amplification was observed when testing human DNA and 22 pathogens or skin commensals. Real-time PCR was applied to 16 clinical samples. Rickettsial DNA was detected in the skin biopsies of three patients. In one patient with severe murine typhus, the typhus group PCR was positive in a skin biopsy from a petechial lesion and seroconversion was later documented. The two other patients with negative typhus group PCR suffered from Mediterranean and African spotted fever, respectively; in both cases, skin biopsy was performed on the eschar. Our duplex real-time PCR showed a good analytical sensitivity and specificity, allowing early diagnosis of rickettsiosis among three patients, and recognition of typhus in one of them

Long-term HIV infection and antiretroviral therapy are associated with bone microstructure alterations in premenopausal women

Summary: We evaluated the influence of long-term HIV infection and its treatment on distal tibia and radius microstructure. Premenopausal eumenorrheic HIV-positive women displayed trabecular and cortical microstructure alterations, which could contribute to increased bone fragility in those patients. Introduction: Bone fragility is an emerging issue in HIV-infected patients. Dual-energy X-ray absorptiometry (DXA) quantified areal bone mineral density (BMD) predicts fracture risk, but a significant proportion of fracture risk results from microstructural alterations. Methods: We studied the influence of long-term HIV infection on bone microstructure as evaluated by high-resolution peripheral quantitative computed tomography (HR-pQCT) in 22 HIV-positive (+ve) premenopausal eumenorrheic women and 44 age- and body mass index (BMI)-matched HIV-negative (−ve) controls. All subjects completed questionnaires regarding calcium/protein intakes and physical activity, and underwent DXA and HR-pQCT examinations for BMD and peripheral skeleton microstructure, respectively. A risk factor analysis of tibia trabecular density using linear mixed models was conducted. Results: In HIV+ve women on successful antiretroviral therapy (undetectable HIV-RNA, median CD4 cell count, 626), infection duration was 16.5 ± 3.5 (mean ± SD) years; median BMI was 22 (IQR, 21-26) kg/m2. More HIV+ve women were smokers (82 versus 50%, p = 0.013). Compared to controls, HIV+ve women had lower lumbar spine (spine T-score −0.70 vs −0.03, p = 0.014), but similar proximal femur BMD. At distal tibia, HIV+ve women had a 14.1% lower trabecular density and a 13.2% reduction in trabecular number compared to HIV−ve women (p = 0.013 and 0.029, respectively). HR-pQCT differences in distal radius were significant for cortical density (−3.0%; p = 0.029). Conclusions: Compared with HIV−ve subjects, premenopausal HIV+ve treated women had trabecular and cortical bone alterations. Adjusted analysis revealed that HIV status was the only determinant of between group tibia trabecular density differences. The latter could contribute to increased bone fragility in HIV+ve patient

Use of Treponema pallidum PCR in Testing of Ulcers for Diagnosis of Primary Syphilis(1.).

Treponema pallidum PCR (Tp-PCR) has been noted as a valid method for diagnosing syphilis. We compared Tp-PCR to a combination of darkfield microscopy (DFM), the reference method, and serologic testing in a cohort of 273 patients from France and Switzerland and found the diagnostic accuracy of Tp-PCR was higher than that for DFM

The "Buruli Score": development of a multivariable prediction model for diagnosis of Mycobacterium ulcerans infection in individuals with ulcerative skin lesions, Akonolinga, Cameroon

Background Access to laboratory diagnosis can be a challenge for individuals suspected of Buruli Ulcer (BU). Our objective was to develop a clinical score to assist clinicians working in resource- limited settings for BU diagnosis. Methododology/Principal Findings Between 2011 and 2013, individuals presenting at Akonolinga District Hospital, Cameroon, were enrolled consecutively. Clinical data were collected prospectively. Based on a latent class model using laboratory test results (ZN, PCR, culture), patients were categorized into high, or low BU likelihood. Variables associated with a high BU likelihood in a multivariate logistic model were included in the Buruli score. Score cut-offs were chosen based on calculated predictive values. Of 325 patients with an ulcerative lesion, 51 (15.7%) had a high BU likelihood. The variables identified for the Buruli score were: characteristic smell (+3 points), yellow color (+2), female gender (+2), undermining (+1), green color (+1), lesion hyposensitivity (+1), pain at rest (-1), size >5cm (-1), locoregional adenopathy (-2), age above 20 up to 40 years (-3), or above 40 (-5). This score had AUC of 0.86 (95% CI 0.82-0.89), indicating good discrimination between infected and non-infected individuals. The cut-off to reasonably exclude BU was set at scores = 4 (PPV 69.0%; 95% CI 49.2-84.7). Patients with intermediate BU probability needed to be tested by PCR. Conclusions/Significance We developed a decisional algorithm based on a clinical score assessing BU probability. The Buruli score still requires further validation before it can be recommended for wide use

Human herpes virus 8 replication during disseminated tuberculosis in a man with human immunodeficiency virus: a case report

INTRODUCTION: Human herpes virus 8 (HHV-8) is mainly responsible for the development of Kaposi's sarcoma and multicentric Castleman's disease in immunocompromised patients with untreated human immunodeficiency virus. Positive viral loads have been described in cases of Kaposi's sarcoma and multicentric Castleman's disease, with higher values found in the latter. We describe the case of a patient with HIV in whom a high level of HHV-8 replication was detected and who contracted an opportunistic disease other than multicentric Castleman's disease or Kaposi's sarcoma. CASE PRESENTATION: A 25-year-old man of West African origin with HIV complained of asthenia, weight loss, fever, and abdominal pain. Physical examination revealed that the patient had adenopathies and hepatosplenomegaly, but no skin or mucosal lesions were seen. Our first presumptive diagnosis was disseminated tuberculosis. However, since the cultures (sputum, bronchoalveolar lavage, blood, urine and lymph node biopsies) for mycobacteria were negative, the diagnosis was expanded to include multicentric Castleman's disease which was supported by high HHV-8 viral loads in the patient's blood: 196,000 copies/ml in whole blood, 39,400 copies/ml in plasma and 260 copies/10E5 in peripheral blood mononuclear cells. However, the histology and positive polymerase chain reaction assay for Mycobacterium tuberculosis complex of a second lymph node biopsy enabled us to conclude that the patient had disseminated tuberculosis and we started the patient on antituberculosis treatment. We analyzed the HHV-8 deoxyribonucleic acid in two other plasma samples (one from six months earlier and the other was 10 days after the positive test) and both yielded negative results. A search for latent and lytic HHV-8 antibodies confirmed that the patient was seropositive for HHV-8 before this episode. CONCLUSION: We describe the case of a patient with HIV who tested positive for asymptomatic HHV-8 replication during an opportunistic disease suggestive of multicentric Castleman's disease. The initial analysis was nullified by the diagnosis of a disease that was unrelated to HHV-8. This case report underlines the need to clarify the full clinical meaning and implication of a positive HHV-8 viral load in patients with AIDS. The diagnosis of multicentric Castleman's disease needs to be studied further to determine its sensitivity and specificity. Finally, when faced with the dilemma of urgently starting chemotherapy on a patient whose condition is deteriorating and whose clinical presentation suggests multicentric Castleman's disease, high HHV-8 viral loads should be interpreted with caution and histological analysis of lymph nodes or liver biopsies should be obtained first

Laboratory diagnosis of Buruli ulcer : challenges and future perspectives

Current options to control Buruli ulcer (BU) are limited, as no effective vaccine is available and knowledge on transmission mechanisms of the causative agent, Mycobacterium ulcerans, is incomplete. Early case detection and rapid initiation of treatment are key elements to prevent the development of large, disfiguring ulcers often associated with permanent physical disability and stigma. BU has been reported from 34 countries, with the greatest disease burden in West Africa and steadily increasing case numbers in south-eastern Australia. The disease can present in a variety of clinical manifestations, including relatively unspecific, painless nodules, plaques, and edema, which may eventually progress to chronic, ulcerative lesions. The clinical diagnosis of BU is therefore complicated by a broad differential diagnosis, particularly in tropical areas, where the prevalence of other skin conditions with a similar appearance is high. With the introduction of combination antibiotic therapy, replacing excision surgery as the standard treatment for BU, pre-treatment confirmation of the clinical diagnosis has further gained in importance to avoid the redundant use of anti-mycobacterial drugs. At present, available confirmatory diagnostic tests either lack sufficient sensitivity/specificity or are centralized and thus often not accessible to patients living in remote, rural areas of Africa. In recognition of this disparity, WHO and other stakeholders have called for new diagnostic tools for BU that can be applied at district hospitals or primary healthcare facilities. This chapter highlights challenges, advances and future prospects for the necessary decentralization of the diagnosis of BU

Hand osteoarthritis: clinical phenotypes, molecular mechanisms and disease management

Osteoarthritis (OA) is a highly prevalent condition and the hand is the most commonly affected site. Patients with hand OA frequently report symptoms of pain, functional limitations, and frustration in undertaking everyday activities. The condition presents clinically with changes to the bone, ligaments, cartilage and synovial tissue, which can be observed using radiography, ultrasonography or MRI. Hand OA is a heterogeneous disorder and is considered to be multifactorial in aetiology. This review provides an overview of the epidemiology, presentation and burden of hand OA, including an update on hand OA imaging (including the development of novel techniques), disease mechanisms and management. In particular, areas for which new evidence has substantially changed the way we understand, consider and treat hand OA are highlighted. For example, genetic studies, clinical trials and careful prospective imaging studies from the past 5 years are beginning to provide insights into the pathogenesis of hand OA that might uncover new therapeutic targets in disease