Protocol for the selection of Mycobacterium tuberculosis spontaneous resistant mutants to d-cycloserine.

Mycobacterium tuberculosis (MTB) is known for its adaptive capability in developing resistance to antibiotics, through the selection of spontaneous mutations that arise during treatment. Generating spontaneous antibiotic-resistant mutants in vitro is challenging but necessary for studying this phenomenon. A protocol was designed and tested to select stable, MTB spontaneous, d-cycloserine (DCS) resistant mutants. Twenty-four colonies resistant to DCS were selected, demonstrating an increase between 1 and 4 times the Minimum Inhibitory Concentration (MIC) set for Mycobacterium tuberculosis H37Rv ATCC 27294 reference strain.

Alteración en la expresión de proteínas transportadoras de colesterol y moléculas inmunomoduladoras en pacientes con VIH-1 / Altered expression of cholesterol transport proteins and immunomodulators molecules in HIV-1 infected patients

Debido a que la terapia antirretroviral no logra controlar la activación inmune asociada a la infección por VIH-1, el estudio de moléculas inmunomoduladoras puede proporcionar alternativas para su control. En este sentido, el propósito de este estudio fue evaluar la expresión transcripcional de moléculas asociadas con el metabolismo del colesterol-HDL (C-HDL) y con la respuesta inflamatoria mediada por el inflamasoma NLRP3 en pacientes infectados con VIH-1. En este estudio transversal, se incluyeron 23 pacientes VIH-1 sin tratamiento antirretroviral, con diferentes estadios de progresión, 7 de los cuales son controladores (Carga viral <2000 copias/mL) y 16 progresores (Carga viral >2000 copias/mL), además de 7 controles sanos. En células mononucleares de sangre periférica, se cuantificaron los niveles de la expresión transcripcional de ABCA-1, ABCA-3, Caspasa-5 y TXNIP mediante RT-PCR. Se evaluó la asociación de estos parámetros con variables demográficas y de laboratorio, y se encontró que los individuos VIH-1 progresores mostraron niveles significativamente menores de TXNIP y ABCA-3, sugiriendo que durante la infección por VIH-1 se produce una alteración en la expresión de estas moléculas. Dada la complejidad de las interacciones inmuno-metabólicas durante la infección por VIH-1, se necesitan estudios adicionales para establecer los mecanismos precisos involucrados en estas alteraciones

Because antiretroviral therapy fails to control the immune activation that occurs during HIV-1 infection, the study of immunomodulatory molecules may provide alternative strategies for their control. In this sense, the aim of the research was to evaluate the transcriptional expression of molecules associated with the metabolism of high-density lipoproteins and with the inflammatory response mediated by the NLRP3 inflammasome in patients infected with HIV-1. This is a cross-sectional study, which included 23 HIV-1 patients without antiretroviral treatment, with different stages of progression, 7 of which are controllers (Viral load <2000 copies/mL) and 16 progressors (Viral load >2000 copies/mL), in addition to 7 healthy controls. In peripheral blood mononuclear cells, the levels of transcriptional expression of ABCA-1, ABCA-3, Caspase-5 and TXNIP were quantified by RT-PCR. The association of these parameters with laboratory and demographic variables was evaluated and it was found that HIV-1 progressing individuals showed significantly lower levels of TXNIP and ABCA-3, suggesting that during HIV-1 infection there is an alteration in the expression of these molecules. Given the complexity of the immuno-metabolic interactions during HIV-1 infection, additional studies are needed to establish the precise mechanisms involved in these alterations

Some Synonymous and Nonsynonymous gyrA Mutations in Mycobacterium tuberculosis Lead to Systematic False-Positive Fluoroquinolone Resistance Results with the Hain GenoType MTBDRsl Assays.

In this study, using the Hain GenoType MTBDRsl assays (versions 1 and 2), we found that some nonsynonymous and synonymous mutations in gyrA in Mycobacterium tuberculosis result in systematic false-resistance results to fluoroquinolones by preventing the binding of wild-type probes. Moreover, such mutations can prevent the binding of mutant probes designed for the identification of specific resistance mutations. Although these mutations are likely rare globally, they occur in approximately 7% of multidrug-resistant tuberculosis strains in some settings.

Systematic interpretation of molecular beacon polymerase chain reaction for identifying rpoB mutations in Mycobacterium tuberculosis isolates with mixed resistant and susceptible bacteria.

Detection of multidrug-resistant tuberculosis (MDR-TB), a frequent cause of treatment failure, takes 2 or more weeks to identify by culture. Rifampicin (RIF) resistance is a hallmark of MDR-TB, and detection of mutations in the rpoB gene of Mycobacterium tuberculosis using molecular beacon probes with real-time quantitative polymerase chain reaction (qPCR) is a novel approach that takes