The Mycobacterium tuberculosis dihydrodipicolinate synthase (Mtb-dapA) is an essential gene. Mtb-DapA catalyzes the aldol condensation between pyruvate and L-aspartate-beta-semialdehyde (ASA) to yield dihydrodipicolinate. In this work we tested the inhibitory effects of structural analogues of pyruvate on recombinant Mtb-DapA (Mtb-rDapA) using a coupled assay with recombinant dihydrodipicolinat...

Purpose Mycobacterium tuberculosis (Mtb) bacilli have been found in retinal pigment epithelial (RPE) cells from uveitis patients without signs of systemic tuberculosis (TB) infection. RPE cells are important for ocular immune privilege and uveitis development. Methods To address a potential role for Mtb-infected RPE cells in the development of uveitis, we delineated the response to Mtb infect...

Background: To evaluate the performance of Xpert MTB/RIF assay for direct detection of Mycobacterium tuberculosis (Mtb) and rifampin resistance in pulmonary and extrapulmonary tuberculosis (TB) patients in China. Material/Methods: We prospectively enrolled 506 TB patients to evaluate sensitivity and specificity of Xpert MTB/ RIF by comparing with Mtb culture, fluorescent staining smear microsco...

Elicitation of CD4 IFN-gamma T cell responses to Mycobacterium tuberculosis (MTB) is a rational vaccine strategy to prevent clinical tuberculosis. Diagnosis of MTB infection is based on T-cell immune memory to MTB antigens. The MTB proteome contains over four thousand open reading frames (ORFs). We conducted a pilot antigen identification study using 164 MTB proteins and MTB-specific T-cells ex...

OBJECTIVES To assess the performance of Xpert MTB/RIF, an automated molecular test for Mycobacterium tuberculosis (MTB) and resistance to rifampin (RIF), against smear microscopy and culture method for diagnosis of MTB infection. Methods: This is a retrospective analysis of 103 respiratory and 137 non-respiratory patient specimens suspected of tuberculosis at King Khalid University Hospital, Ri...

Among fluoroquinolone-resistant Mycobacterium tuberculosis (FQr-MTB) isolates, mutation at positions 90, 91, and 94 in gyrA gene and at positions 495, 516, and 533 in gyrB gene have been frequently reported. In this study, 35 isolates of FQr-MTB were collected from Siriraj Hospital and Chest Disease Institute. The quinolone-resistance-determining regions (QRDR) of gyrA and gyrB genes in all 35 ...

Modulation of immune cell apoptosis is a key evasion strategy utilized by Mycobacterium tuberculosis (Mtb). To be able to multiply within macrophages, the bacterium delays apoptosis and down-regulates pro-inflammatory activation in these cells, whereas apoptosis is rapidly induced in the potently bactericidal neutrophils. Initial host-pathogen interactions between neutrophils and Mtb, subsequen...

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Mycobacterium tuberculosis (MTB) persists inside macrophages despite vigorous immune responses. MTB and MTB 19-kDa lipoprotein inhibit class II MHC (MHC-II) expression and Ag processing by a Toll-like receptor 2-dependent mechanism that is shown in this study to involve a defect in IFN-gamma induction of class II transactivator (CIITA). Exposure of macrophages to MTB or MTB 19-kDa lipoprotein i...

The intracellular pathogen Mycobacterium tuberculosis (Mtb) lives within phagosomes and also disrupts these organelles to access the cytosol. The host pathways and mechanisms that contribute to maintaining Mtb phagosome integrity have not been investigated. Here, we examined the spatiotemporal dynamics of Mtb-containing phagosomes and identified an interferon-gamma-stimulated and Rab20-dependen...