RESUMEN
INTRODUCTION: There is a constant search for more sensitive and specific laboratory markers for tuberculosis (TB) infection. The early detection of TB in HIV co infected individuals is a diagnostic challenge. This is further compounded in those harbouring extrapulmonary disease. AIM: To evaluate the use of multiple Enzyme Linked Immunosorbent Assays (ELISA) quantifying antibody responses to 38kDa, LAM and ESAT-6 M.tb antigens in detection of TB in patients with TB and HIV-TB co-infection. MATERIALS AND METHODS: This is a cross-sectional study carried out in Hyderabad, India. Patient groups included 124 HIV-TB {62 with pulmonary TB (PTB) and 62 with extrapulmonary TB (ETB)}, 39 TB, 56 HIV and 57 healthy subjects (HS). A combination of anti 38kDa and LAM ELISAs measuring IgG, IgM and IgA levels and another ELISA measuring anti ESAT-6 combined antibody levels of IgG, IgM and IgA were evaluated. One-way ANOVA was performed to compare antibody responses among groups. To assess the efficacy of multiple ELISAs in detecting TB, concomitant seropositivity of an individual for all four ELISAs were evaluated for sensitivity and specificity. RESULTS: A single ELISA carried out to detect TB in HIV patients showed a sensitivity ranging from 39% to 72%. The sensitivities of concomitant evaluation of multiple ELISAs were 92% for any single, 72% for any two, 44% for any three and 14% for any four. Based on the specificities, a simple algorithm for TB detection can be deduced. When four ELISAs are positive (specificity 100%) in a patient-confirmed TB; when three ELISAs are positive (specificity 98%) - probably TB; when two ELISAs are positive (specificity 95%) - possibly TB; and when one ELISA is positive (specificity 70%) - suspicion of TB. CONCLUSION: The present study establishes the value of combining two or more M.tb antigen based ELISAs to enhance the sensitivity and specificity of TB detection in patients with tuberculosis as well as in those co-infected with HIV.
RESUMEN
With the heightened interest in Bacillus anthracis as a potential biological threat agent, novel drug targets identification is of great importance in drug discovery. This study considered a genome-wide approach to identify 270 non-redundant, non-human homologous genes and 103 essential genes of the bacteria as putative drug targets. Sub-cellular localisation of each drug target was annotated using PSORTb 3.0 and confirmation by a hybrid support vector machine analysis identified 16 membrane-bound genes with reliability index ≥4. SPAAN analysis predicted 3 adhesion-like proteins and BLAST against the MEROPS database identified 7 peptidases with inhibitors. As a case study, a homology model was built for the ptsG gene using Modeller 9v8. The work reported here identified a small subset of potential drug targets involved in vital aspects of the metabolism of pathogen, persistence, virulence and cell wall biosynthesis. Thus, this manifold workflow can speed up the process of drug target discovery.