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Operational research for effective and integrated tuberculosis control
No full textMonografieën vna de Vakgroep Maatschappelijke Gezondheidkund
Comparative evaluation of freeze-dried and liquid antigens in the direct agglutination test for serodiagnosis of visceral leishmaniasis (ITMA-DAT/VL)
No full textThe definitive version is available at www3.interscience.wiley.comOBJECTIVE: The direct agglutination test (DAT) for visceral leishmaniasis (VL) with liquid (LQ) antigen is known to be only moderately reproducible because of inter-observer and batch-to-batch variability as well as its sensitivity to temperature and shaking during transport. We evaluated a DAT with freeze-dried (FD) antigen and compared it with the LQ antigen version. METHODS: Blood samples of clinical VL suspects and healthy endemic controls were collected in Sudan, Nepal and India. Both test versions were performed in duplicate in the respective countries and in the reference laboratory. Interbatch variability and stability tests were conducted and agreement was examined within and between centres on a dichotomic scale by Cohen's kappa as well as on a continuous scale through Bland-Altman plots. RESULTS: The FD antigen remains fully active even after storage at 45 degrees C for 24 months. Using a cut-off titre of 1:6400, the agreement between the FD and the LQ formats was excellent. CONCLUSION: The major advantages of FD antigen are its better stability at higher temperatures and its longer shelf life, which make it much more suitable than the LQ version for use in the field
Male circumcision and risk of syphilis, chancroid, and genital herpes: a systematic review and meta-analysis [commentary]
No full textNewer diagnostics for tuberculosis and multi-drug resistant tuberculosis
No full textNot the final published versionPURPOSE OF REVIEW: This article will review some of the recent developments for the rapid diagnosis and detection of drug resistance in tuberculosis. RECENT FINDINGS: Tuberculosis remains one of the major causes of death from a single infectious agent worldwide. Of great concern for tuberculosis control is the emergence of drug resistance since there is no cure for some multidrug-resistant strains of M. tuberculosis, and there is concern that they may spread around the world, stressing the need for additional control measures such as new diagnostics and better drugs for treatment. Recent advances in molecular biology and a better understanding of the molecular basis of drug resistance have provided new tools for rapid tuberculosis diagnosis. Other non-conventional diagnostic approaches have also been proposed. Nucleic acid amplification techniques, both commercial and in-house, and non-molecular methods are being evaluated. The overall accuracy of most of these tests is promising and some of them can be easily implemented in clinical mycobacteriology laboratories. SUMMARY: New genotypic and phenotypic methods for rapid diagnosis and detection of drug resistance have been developed and tested both in M. tuberculosis strains as well as in clinical samples. Further controlled evaluations are necessary in high-endemic countries for their eventual implementation in the routine diagnostic systems
Dominant ex vivo cross-stimulation of CD8+ T-cells with whole soluble Gag protein in HIV-infected subjects
No full textNot the final published versionBACKGROUND: Soluble HIV proteins are often used to detect HIV-specific CD4+ T-helper cell responses in vitro. However, exogenous antigens can also indirectly stimulate CD8+ T-cells and thus complicate assessment of CD4+ T-cell responses. OBJECTIVE: To analyze the extent of in vitro HIV-1 Gag p55 protein cross-stimulation to CD8+ T-cells in therapy-naive and highly active antiretroviral therapy (HAART)-treated HIV patients and to correlate this phenomenon with HIV disease progression. METHODS: Gag protein-stimulated T-cell responses were measured in total and CD8-depleted peripheral blood mononuclear cells (PBMCs) by interferon (IFN)-gamma enzyme-linked immunosorbent spot (ELISPOT) assays in 20 therapy-naive and 60 HAART-treated HIV patients. Numbers of spot forming cells (SFCs) relative to CD4+ and CD8+ T-cell subsets were calculated. Gag protein-stimulated responses were correlated with markers of disease progression. RESULTS: Stimulation of PBMC with HIV-1 Gag protein induced higher CD8+ T-cell responses than CD4+ T-cell responses in both therapy-naive and HAART-treated HIV patients (P < 0.001). Gag protein cross-stimulation of CD8+ T-cells was higher in therapy-naive than in HAART-treated HIV patients (P < 0.001). In HAART-treated HIV patients, we detected an inverse correlation between Gag protein cross-stimulation of CD8+ T-cells and the CD4 count (R = -0.311; P = 0.016). Depletion of CD14+ cells abrogated the responses, suggesting that Gag protein cross-stimulation of CD8+ T-cells depends on antigen processing and presentation by antigen-presenting cells (APCs). CONCLUSIONS: HIV protein cross-presentation to CD8+ T-cells should be taken into account when detecting HIV-specific T-cell responses by stimulation of PBMCs with whole exogenous antigens
Evaluation of phage assay for rapid phenotypic detection of rifampicin resistance in Mycobacterium tuberculosis
No full textBACKGROUND: Conventional methods for susceptibility testing require several months before results can be reported. However, rapid methods to determine drug susceptibility have been developed recently. Phage assay have been reported as a rapid useful tools for antimicrobial susceptibility testing. The aim of this study was to apply the Phage assay for rapid detection of resistance on Mycobacterium tuberculosis strains in Cuba. METHODS: Phage D29 assay was performed on 102 M. tuberculosis strains to detect rifampicin resistance. The results were compared with the proportion method (gold standard) to evaluate the sensitivity and specificity of Phage assay. RESULTS: Phage assay results were available in 2 days whereas Proportion Methods results were obtain in 42 days. A total of 44 strains were detected as rifampicin resistant by both methods. However, one strains deemed resistant by Proportion Methods was susceptible by Phage assay. The sensitivity and specificity of Phage assay were 97.8 % and 100% respectively. CONCLUSION: Phage assay provides rapid and reliable results for susceptibility testing; it's easy to perform, requires no specialized equipment and is applicable to drug susceptibility testing in low income countries where tuberculosis is a major public health problem
Comparison of preservation methods of Rhipicephalus appendiculatus (Acari: Ixodidae) for reliable DNA amplification by PCR
No full textFive differently preserved groups of adult Rhipicephalus appendiculatus specimens were compared for quality of DNA extracted. Three methods were used to extract DNA from specimens i.e. two simple mosquito validated DNA extraction methods and a tick validated method. Extraction of DNA from tick legs was attempted. The quality of DNA extracted was evaluated by the success of PCR amplification of the ITS2 gene and the mitochondrial COI gene fragment. Fresh specimens (i.e. killed just before extraction) had the highest success of DNA amplification followed by specimens killed in ethanol and subsequently stored in the refrigerator (4 degrees C). There was no significant difference in amplification success between cryopreserved and 70% ethanol preserved specimens. It was possible to amplify DNA from legs of ticks. Sequenced ITS2 amplicon of template obtained from legs of ticks was as legible as those from whole tick extract. The two mosquito validated DNA extraction methods showed a significantly lower amplification success than the tick validated protocol
