Crystal structure of dihydroneopterin aldolase from Mycobacterium tuberculosis associated with 8-mercaptoguanine, and development of novel S8-functionalized analogues as inhibitors: Synthesis, enzyme inhibition, in vitro toxicity and antitubercular activity.

The crystallographic structure of the FolB enzyme from Mycobacterium tuberculosis (MtFolB), complexed with its inhibitor 8-mercaptoguanine (8-MG), was elucidated at a resolution of 1.95 Å. A novel series of S8-functionalized 8-MG derivatives were synthesised and evaluated as in vitro inhibitors of dihydroneopterin aldolase (DHNA, EC 4.1.2.25) activity of MtFolB. These compounds exhibited IC50 values in the submicromolar range. Evaluation of the activity for five compounds indicated their inhibition mode and inhibition constants. Molecular docking analyses were performed to determine the enzyme-inhibitor intermolecular interactions and ligand conformations upon complex formation. The inhibitory activities of all compounds against the M. tuberculosis H37Rv strain were evaluated. Compound 3e exhibited a minimum inhibitory concentration in the micromolar range. Finally, Compound 3e showed no apparent toxicity in both HepG2 and Vero cells. The findings presented herein will advance the quest for novel, specific inhibitors targeting MtFolB, an attractive molecular target for TB drug development.

Paradoxical Reaction in Intraocular Tuberculosis: Report of Three Cases.

PURPOSE: To present paradoxical reaction (PR) in three cases with ocular tuberculosis (OTB) treated with antitubercular therapy (ATT), highlighting diagnostic challenges and treatment strategies. METHODS: We retrospectively reviewed clinical records of three OTB patients presenting with paradoxical worsening after ATT initiation at two Brazilian university hospitals. RESULTS: The patients (2 males, 1 female) experienced worsening clinical presentation (increased inflammation, vision loss) within two to three weeks after initiating ATT. One patient who was HIV-positive with unilateral multifocal choroiditis developed PR soon after starting antiretroviral therapy. The second patient presented with a choroidal tuberculoma in both eyes. The third patient also had multifocal choroiditis and developed a localized choroidal elevation with a double-layer sign as a manifestation of PR. All patients were maintained on ATT therapy in association with corticosteroids and experienced improvement of inflammatory signs. CONCLUSION: This case series highlights the potential for PR in OTB patients. Close monitoring and prompt therapeutic adjustments are crucial for management success.

Evaluation of concordance of new QuantiFERON-TB Gold Plus platforms for Mycobacterium tuberculosis infection diagnosis in a prospective cohort of household contacts.

Interferon-gamma (IFN-γ) release assays play a pivotal role in tuberculosis infection (TBI) diagnosis, with QuantiFERON-TB Gold Plus-an enzyme-linked immunosorbent assay (ELISA)-among the most widely utilized. Newer QuantiFERON-TB platforms with shorter turnaround times were recently released. We aimed to evaluate these platforms' agreement in the diagnosis of TBI. Blood samples from a prospective cohort of tuberculosis household contacts were collected at baseline and after 12 weeks of follow-up, and tested with LIAISON, an automated chemiluminescence immunoassay (CLIA) system, QIAreach, a lateral flow (QFT-LF) semi-automated immunoassay, and the ELISA QuantiFERON-TB Gold Plus platform. Test concordances were analyzed. ELISA vs CLIA overall agreement was 83.3% for all tested samples (120/144) [Cohen's kappa coefficient (κ): 0.66 (95% CI: 0.54-0.77)]. Samples positive with CLIA provided consistently higher IFN-γ levels than with ELISA (P < 0.001). Twenty-four (16.7%) discordant pairs were obtained, all CLIA-positive/ELISA-negative: 15 (62.5%) had CLIA IFN-γ levels within borderline values (0.35-0.99 IU/mL) and 9 (37.5%) >0.99 IU/mL. QFT-LF showed only 76.4% (68/89) overall agreement with ELISA [κ: 0.53 (95% CI: 0.37-0.68)] with 21 (23.6%) discordant results obtained, all QFT-LF-positive/ELISA-negative. Overall concordance between ELISA and CLIA platforms was substantial, and only moderate between ELISA and QFT-LF. The CLIA platform yielded higher IFN-γ levels than ELISA, leading to an almost 17% higher positivity rate. The techniques do not seem interchangeable, and validation against other gold standards, such as microbiologically-confirmed tuberculosis disease, is required to determine whether these cases represent true new infections or whether CLIA necessitates a higher cutoff. IMPORTANCE: Tuberculosis is an airborne infectious disease caused by Mycobacterium tuberculosis that affects over 10 million people annually, with over 2 billion people carrying an asymptomatic tuberculosis infection (TBI) worldwide. Currently, TBI diagnosis includes tuberculin skin test and the blood-based interferon-gamma (IFN-γ) release assays, with Qiagen QuantiFERON-TB Gold Plus (QFT) being among those most widely utilized. We evaluated Qiagen's newer QFT platforms commercially available in a prospective cohort of tuberculosis contacts. A substantial agreement was obtained between the current QFT-enzyme-linked immunosorbent assay (ELISA) and the new QFT-chemiluminescence immunoassay (CLIA) platform, although QFT-CLIA provided higher concentrations of IFN-γ, leading to a 16.6% higher positivity rate. We highlight that both platforms may not be directly interchangeable and that further validation is required.

Chemical composition and antimycobacterial, anti-Malassezia furfur and cytotoxic activities of essential oils from Callistemon viminalis (Sol. ex Gaertn.) G. Don leaves and flowers.

Callistemon viminalis has been widely known due to its therapeutic properties. Tuberculosis is a deadly infectious disease caused predominantly by Mycobacterium tuberculosis. Other respiratory diseases may also be caused by nontuberculous mycobacteria. Malassezia furfur causes dermal inflammation and tissue damage. This study aimed to evaluate in vitro inhibitory effects of essential oils (EOs) from C. viminalis leaves (EO-CL) and flowers (EO-CF) against M. tuberculosis, Mycobacterium kansasii, Mycobacterium avium and M. furfur strains. Their cytotoxic activity was evaluated by the brine shrimp assay. Resulting MIC values of all EOs under study were promising since they ranged from 50 to 100 µg/mL. Both EO-CL and EO-CF showed nontoxicity against Artemia salina by the brine shrimp assay (LC50 > 1000 µg/mL). GC-FID and GC-MS analyses showed that 1,8-cineole was the major component of both EOs. These results revealed the promising potential of EO-CL and EO-CF to develop new antibacterial and antifungal drugs.

Actualización en la detección de la tuberculosis a través de pruebas moleculares / An update on the detection of tuberculosis through molecular testing

La tuberculosis es una enfermedad infecciosa respiratoria que afecta a un tercio de la población mundial y es una amenaza significativa para la salud global. La detección de la tuberculosis de manera temprana es crucial para un tratamiento eficaz y prevenir su propagación. Una solución para mejorar el diagnóstico y abordar la resistencia a los medicamentos antituberculosos es el uso de pruebas moleculares de alto rendimiento para la identificación del Mycobacterium tuberculosis y su susceptibilidad. Este estudio de revisión narrativa busca describir las generalidades, la eficacia, la sensibilidad, las ventajas y las limitaciones de las principales pruebas moleculares; Truenat® MTB, MTB plus y MTB-RIF, Abbott RealTime MTB y MTB RIF/INH en el sistema m2000sp y m2000rt y FluoroType MTBDR, además, de compararlas con GeneXpert MTB/RIF o Xpert Ultra, utilizadas para la detección del patógeno resistente a medicamentos tuberculosos. Estas pruebas utilizan diversas técnicas para la detección del ADN del Mycobacterium tuberculosis y la cuantificación de la carga bacteriana con alta sensibilidad y especificidad, resultados rápidos, reducción de los errores humanos, así como la detección temprana de cepas drogo-resistentes. A pesar de que requieren infraestructura especializada y competencias profesionales para su implementación, representan avances significativos con el potencial de mejorar la atención sanitaria y la gestión de la tuberculosis. Estas pruebas moleculares, comparadas con el GeneXpert, son una alternativa viable, aunque esta última tecnología sigue siendo la preferida en áreas con recursos limitados

Tuberculosis is a respiratory infectious disease that affects one third of the world's population and is a significant threat to global health. Detecting tuberculosis early is crucial for effective treatment and preventing its spread. One solution to improve diagnosis and address antituberculosis drug resistance is the use of high-throughput molecular tests for the identification of Mycobacterium tuberculosis and its susceptibility. This narrative review study seeks to describe the generalities, efficacy, sensitivity, advantages and limitations of the main molecular tests: Truenat® MTB, MTB plus and MTB-RIF, Abbott RealTime MTB and MTB RIF/INH on the m2000sp and m2000rt system and FluoroType MTBDR, and to compare them with GeneXpert MTB/RIF or Xpert Ultra, used for the detection of the tuberculosis drug-resistant pathogen. These tests use various techniques for the detection of Mycobacterium tuberculosis DNA and quantification of bacterial load with high sensitivity and specificity, rapid results, reduction of human error, as well as early detection of drug-resistant strains

Mycobacterium tuberculosis Beijing in the State of Nuevo Leon, Mexico.

Tuberculosis remains a serious threat to human health as an infectious disease in Mexico. Data about the genotypes of circulating Mycobacterium tuberculosis isolates (MTB) in the State of Nuevo Leon, Mexico are scarce. We aimed to determine the genotypes of circulating MTB belonging to the Beijing lineage recovered from patients in the State of Nuevo Leon, Mexico. A total of 406 MTB isolates from this state were genotyped using the spoligotyping method and 18-locus MIRU-VNTR. Lineage classification and MTB transmission analysis were performed. Based on the spoligotyping analysis, we found 24 strains belonging to the Beijing genotype that were characterized phylogenetically. The MIRUs showed greater discriminatory power than the standard RFLP-IS6110 method; therefore, the greatest allelic diversity among the Beijing strains was observed with MIRU10, MIRU31, MIRU39, MRU40, and MIRU 26. MVLA analysis showed a profile variation between Beijing and non-Beijing strains. The minimum spanning tree (MST) showed that 79% (19) of the strains are related. All Beijing strains exhibited the deletion of region TbD1, which is a characteristic of modern strains. The application of spoligotyping and MIRU-VNTR-18 methods together proved to be more sensitive, discriminatory, and rapid than the standard method for the epidemiological analysis of Mycobacterium Beijing isolates. This study is one of the first to describe the genomic diversity of M. Beijing in the State of Nuevo Leon, Mexico.

Factors Associated With Extrapulmonary Tuberculosis in Southeastern Mexico: A Case-Control Study.

INTRODUCTION: Extrapulmonary tuberculosis (EPTB) is a disease that can affect any organ or tissue. Due to its potential to cause more dangerous sequelae and the barriers to its timely diagnosis, greater clinical awareness of this disease is crucial. This study aimed to identify the factors associated with EPTB in the population of Oaxaca, Mexico. METHODS: This is an unpaired case-control study. The cases were patients with EPTB+ while the controls were patients with pulmonary tuberculosis (PTB+) registered in the Tuberculosis Epidemiological Surveillance System. Sociodemographic, clinical, and microbiological variables were recovered. Bivariate analyses were performed and logistic regression analyses were performed to calculate the odds ratio (OR). RESULTS: A total of 75 EPTB+ cases and 300 PTB+ controls were included. Of the total sample, 57.1% were men and 60.3% indigenous. The most frequent clinical presentations of EPTB+ were nodal (21.3%), miliary (21.3%), and breast (20.0%). According to logistic regression analysis, age <40 years (OR: 2.25 (95% CI: 1.13-4.49), female sex (OR: 1.92 (95% CI: 1.03-3.56)], urban residence (OR: 2.25 (95% CI: 1.11-4.55)), comorbidity with human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) (OR: 3.46 (95% CI: 1.31-9.10)), dyspnea (OR: 2.67 (1.22-5.82)), and adenopathy (OR: 3.38 (95% CI: 1.42-8.06)) were positively associated with EPTB+. CONCLUSION: These results can serve as a basis for screening EPTB+, thus improving the preventive and diagnostic capacity of local health services, taking as a starting point women under 40 years of age and patients with HIV/AIDS in urban areas, as well as the presence of adenopathy and dyspnea as clinical characteristics of the disease.

Coastal natural products: a review applied to antimycobacterial activity.

Despite the many advances in drug research, natural products are still being explored as a promising source for discovering new bioactive compounds to treat global diseases such as tuberculosis. However, there is a lack of studies and information about coastal natural products, which thrive in the transitional environment between two different ecosystems and produce unique secondary metabolites. Mangroves, estuaries, and mudflats make up areas for coastal species and have shown promising results in antituberculosis research, some of them are present in hotspot areas. This review focuses on research conducted in coastal environments and explores the reasons why these natural products tend to outperform non-coastal ones against the causative agent of tuberculosis, Mycobacterium tuberculosis.

A consensus reverse docking approach for identification of a competitive inhibitor of acetyltransferase enhanced intracellular survival protein from Mycobacterium tuberculosis.

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb), which remains a significant global health challenge. The emergence of multidrug-resistant (MDR) Mtb strains imposes the development of new therapeutic strategies. This study focuses on the identification and evaluation of potential inhibitors against Mtb H37Ra through a comprehensive screening of an in-house chemolibrary. Subsequently, a promising pyrimidine derivative (LQM495) was identified as promising and then further investigated by experimental and in silico approaches. In this context, computational techniques were used to elucidate the potential molecular target underlying the inhibitory action of LQM495. Then, a consensus reverse docking (CRD) protocol was used to investigate the interactions between this compound and several Mtb targets. Out of 98 Mtb targets investigated, the enhanced intracellular survival (Eis) protein emerged as a target for LQM495. To gain insights into the stability of the LQM495-Eis complex, molecular dynamics (MD) simulations were conducted over a 400 ns trajectory. Further insights into its binding modes within the Eis binding site were obtained through a Quantum mechanics (QM) approach, using density functional theory (DFT), with B3LYP/D3 basis set. These calculations shed light on the electronic properties and reactivity of LQM495. Subsequently, inhibition assays and kinetic studies of the Eis activity were used to investigate the activity of LQM495. Then, an IC50 value of 11.0 ± 1.4 µM was found for LQM495 upon Eis protein. Additionally, its Vmax, Km, and Ki parameters indicated that it is a competitive inhibitor. Lastly, this study presents LQM495 as a promising inhibitor of Mtb Eis protein, which could be further explored for developing novel anti-TB drugs in the future.

Genetic Characterization and Population Structure of Drug-Resistant Mycobacterium tuberculosis Isolated from Brazilian Patients Using Whole-Genome Sequencing.

The present study aimed to determine the genetic diversity of isolates of Mycobacterium tuberculosis (Mtb) from presumed drug-resistant tuberculosis patients from several states of Brazil. The isolates had been submitted to conventional drug susceptibility testing for first- and second-line drugs. Multidrug-resistant (MDR-TB) (54.8%) was the most frequent phenotypic resistance profile, in addition to an important high frequency of pre-extensive resistance (p-XDR-TB) (9.2%). Using whole-genome sequencing (WGS), we characterized 298 Mtb isolates from Brazil. Besides the analysis of genotype distribution and possible correlations between molecular and clinical data, we determined the performance of an in-house WGS pipeline with other online pipelines for Mtb lineages and drug resistance profile definitions. Sub-lineage 4.3 (52%) was the most frequent genotype, and the genomic approach revealed a p-XDR-TB level of 22.5%. We detected twenty novel mutations in three resistance genes, and six of these were observed in eight phenotypically resistant isolates. A cluster analysis of 170 isolates showed that 43.5% of the TB patients belonged to 24 genomic clusters, suggesting considerable ongoing transmission of DR-TB, including two interstate transmissions. The in-house WGS pipeline showed the best overall performance in drug resistance prediction, presenting the best accuracy values for five of the nine drugs tested. Significant associations were observed between suffering from fatal disease and genotypic p-XDR-TB (p = 0.03) and either phenotypic (p = 0.006) or genotypic (p = 0.0007) ethambutol resistance. The use of WGS analysis improved our understanding of the population structure of MTBC in Brazil and the genetic and clinical data correlations and demonstrated its utility for surveillance efforts regarding the spread of DR-TB, hopefully helping to avoid the emergence of even more resistant strains and to reduce TB incidence and mortality rates.

Tuberculosis extrapulmonar, la gran simuladora / Extrapulmonary tuberculosis, the great pretender

La tuberculosis es una enfermedad infecciosa considerada un problema de salud pública ya que constituye una de las principales causas de morbimortalidad a nivel mundial; su forma clínica más frecuente es la tuberculosis pulmonar, sin embargo, esta enfermedad también puede afectar estructuras extrapulmonares cuyo diagnóstico generalmente es tardío debido a que los síntomas y signos son inespecíficos. En este artículo se presenta un caso clínico de tuberculosis extrapulmonar (miliar, sistema nervioso central e intestinal) en el Hospital Universitario de Puebla (AU)

Tuberculosis is an infectious disease considered a public health problem since it is one of the main causes of morbidity and mortality worldwide; the most common clinical form is pulmonary tuberculosis; however, this disease can also affect extrapulmonary structures whose diagnosis is generally late because the symptoms and signs are nonspecific. This article presents a clinical case of extrapulmonary tuberculosis (miliary, central nervous system and intestinal) at the University Hospital of Puebla (AU)

Síndrome medular completo secundario a mielitis infecciosa causada por Mycobacterium tuberculosis. Informe de caso / Central spinal cord syndrome secondary to infectious myelitis caused by Mycobacterium Tuberculosis

Introducción: La tuberculosis, un problema de salud pública a nivel mundial que afecta a la población. Causada por Mycobacterium tuberculosis, se transmite a través de gotas de saliva y la presentación extrapulmonar afecta 5­45% de la población infectada. La tuberculosis de columna vertebral es una enfermedad crónica y progresiva, secundaria a la diseminación de un foco primario, que puede pasar desapercibido. Descripción del caso: Paciente masculino con fiebre de 4 días de evolución, nocturna, con diaforesis, debilidad de fuerza de miembros superiores e inferiores bilateral; miembros inferiores con (0) fuerza y miembros superiores (1), ausencia de reflejos osteotendinosos en ambas extremidades, nivel sensitivo C4, con ausencia de control de esfínteres. El diagnóstico se estableció mediante toracocentesis diagnóstica, realizando GeneXpert y cultivo de líquido pleural, positivo para tuberculosis y negativo para micobacteria resistente; resonancia magnética con gadolinio identifica área hiperintensa cervical medular de C2 hasta C4, produciendo aumento en el diámetro de la médula espinal. Se inició tratamiento tetraconjugado: isoniazida, rifampicina, pirazinamida y etambutol. Cuatro semanas posteriores al comienzo de tratamiento paciente presenta (2) fuerza en miembros inferiores y (3) en miembros superiores, continuando con terapia física. Conclusión: la tuberculosis se presenta de maneras muy diversas y se debe tener presente en pacientes jóvenes sin antecedentes personales patológicos que presenten cuadros de fiebre como uno de los primeros síntomas. Pruebas diagnósticas serológicas, GeneXpert y de imagen como la resonancia magnética ayudan en establecer un diagnóstico. La tuberculosis debe considerarse siempre en un proceso infeccioso que se desconoce etiología...(AU)

Immunohistochemistry and real-time Polymerase Chain Reaction: importance in the diagnosis of intestinal tuberculosis in a Peruvian population.

INTRODUCTION: The diagnosis of intestinal tuberculosis is challenging even nowadays. This study aims to report the positivity rates of new diagnostic methods such as immunohistochemistry and Real-Time Polymerase Chain Reaction in patients with intestinal tuberculosis, as well as describe the pathological and endoscopic features of intestinal tuberculosis in our population. METHODS: This was a retrospective observational study conducted in patients diagnosed with intestinal tuberculosis, between 2010 to 2023 from the Hospital Nacional Daniel Alcides Carrion and a Private Pathology Center, both located in Peru. Clinical data was obtained, histologic features were independently re-evaluated by three pathologists; and immunohistochemistry and real-time Polymerase Chain Reaction evaluation were performed. The 33 patients with intestinal tuberculosis who fulfilled the inclusion criteria were recruited. RESULTS: Immunohistochemistry was positive in 90.9% of cases, while real-time Polymerase Chain Reaction was positive in 38.7%. The ileocecal region was the most affected area (33.3%), and the most frequent endoscopic appearance was an ulcer (63.6%). Most of the granulomas were composed solely of epithelioid histiocytes (75.8%). Crypt architectural disarray was the second most frequent histologic finding (78.8%) after granulomas, but most of them were mild. CONCLUSION: Since immunohistochemistry does not require an intact cell wall, it demonstrates higher sensitivity compared to Ziehl-Neelsen staining. Therefore, it could be helpful for the diagnosis of paucibacillary tuberculosis.

Breaking barriers: The potential of nanosystems in antituberculosis therapy.

Tuberculosis (TB), caused by Mycobacterium tuberculosis, continues to pose a significant threat to global health. The resilience of TB is amplified by a myriad of physical, biological, and biopharmaceutical barriers that challenge conventional therapeutic approaches. This review navigates the intricate landscape of TB treatment, from the stealth of latent infections and the strength of granuloma formations to the daunting specters of drug resistance and altered gene expression. Amidst these challenges, traditional therapies often fail, contending with inconsistent bioavailability, prolonged treatment regimens, and socioeconomic burdens. Nanoscale Drug Delivery Systems (NDDSs) emerge as a promising beacon, ready to overcome these barriers, offering better drug targeting and improved patient adherence. Through a critical approach, we evaluate a spectrum of nanosystems and their efficacy against MTB both in vitro and in vivo. This review advocates for the intensification of research in NDDSs, heralding their potential to reshape the contours of global TB treatment strategies.

Genetic Diversity of Mycobacterium tuberculosis Strains Isolated from HIV-Infected Patients in Mexico.

There has been very limited investigation regarding the genetic diversity of Mycobacterium tuberculosis (MTb) strains isolated from human immunodeficiency virus (HIV)-infected patients in Mexico. In this study, we isolated 93 MTb strains from pulmonary and extrapulmonary samples of HIV-infected patients treated in a public hospital in Mexico City to evaluate the genetic diversity using spoligotyping and mycobacterial interspersed repetitive unit-variable-number tandem-repeat (MIRU-VNTR) typing (based on 24 loci). The cohort comprised 80 male and 13 female individuals. There was a positive correlation between a high HIV viral load (>100,000 copies) and extrapulmonary tuberculosis (TB) (r = 0.306, p = 0.008). Lineage 4 was the most frequent lineage (79 strains). In this lineage, we found the H clade (n = 24), including the Haarlem, H3, and H1 families; the T clade (n = 22), including T1 and T2; the X clade (n = 15), including X1 and X3; the LAM clade (n = 14), including LAM1, LAM2, LAM3, LAM6, and LAM9; the S clade (n = 2); Uganda (n = 1); and Ghana (n = 1). We also found 12 strains in the EAI clade belonging to lineage 1, including the EAI2-Manila and EAI5 families. Interestingly, we identified one strain belonging to the Beijing family, which is part of lineage 2. One strain could not be identified. This study reports high genetic diversity among MTb strains, highlighting the need for a molecular epidemiological surveillance system that can help to monitor the spread of these strains, leading to more appropriate measures for TB control in HIV-infected patients.

Prevalence, drug resistance, and genotypic diversity of the RDRio subfamily of Mycobacterium tuberculosis in Ecuador: a retrospective analysis for years 2012-2016.

Introduction: A major sublineage within the Mycobacterium tuberculosis (MTB) LAM family characterized by a new in-frame fusion gene Rv3346c/55c was discovered in Rio de Janeiro (Brazil) in 2007, called RDRio, associated to drug resistance. The few studies about prevalence of MTB RDRio strains in Latin America reported values ranging from 3% in Chile to 69.8% in Venezuela, although no information is available for countries like Ecuador. Methods: A total of 814 MTB isolates from years 2012 to 2016 were screened by multiplex PCR for RDRio identification, followed by 24-loci MIRU-VNTR and spoligotyping. Results: A total number of 17 MTB RDRio strains were identified, representing an overall prevalence of 2.09% among MTB strains in Ecuador. While 10.9% of the MTB isolates included in the study were multidrug resistance (MDR), 29.4% (5/17) of the RDRio strains were MDR. Discussion: This is the first report of the prevalence of MTB RDRio in Ecuador, where a strong association with MDR was found, but also a very low prevalence compared to other countries in Latin America. It is important to improve molecular epidemiology tools as a part of MTB surveillance programs in Latin America to track the transmission of potentially dangerous MTB stains associated to MDR TB like MTB RDRio.

Utilidad de GeneXpert MTB/RIF en el diagnóstico de tuberculosis frente a la baciloscopia / Utility of GeneXpert MTB/RIF in the Diagnosis of Tuberculosis Compared to Sputum Smear Microscopy

Introducción: La implementación de un método diagnóstico adecuado y eficiente es crucial para la detección temprana de la tuberculosis. Esto no solo permite un control efectivo de la enfermedad para evitar su transmisión y progresión hacia estadios más graves, además previene el desarrollo de resistencia a los fármacos en los pacientes.Objetivo: Evaluar la utilidad de la prueba molecular GeneXpert MTB/RIF en el diag-nóstico de Mycobacterium tuberculosis complex, en comparación con la bacilos-copia, utilizando el cultivo como referencia.Material y Métodos: Se realizó un estudio descriptivo, observacional y no expe-rimental de corte transversal, se incluyeron 253 muestras de pacientes de ambos sexos y de variados rangos de edad, que fueron evaluadas mediante baciloscopia, GeneXpert MTB/RIF y cultivo. El estudio se centró en muestras procesadas en un Hospital público de la ciudad de Quito durante el período de enero de 2021 a mayo de 2022Resultados: La prueba molecular GeneXpert MTB/RIF mostró una sensibilidad del 94,7% y una especificidad del 93,9% para el diagnóstico de Mycobacterium tu-berculosis complex. Además, se identificó un caso de resistencia a la rifampicina.Conclusión: Este estudio confirma la eficacia de la prueba molecular GeneXpert MTB/RIF sobre la baciloscopia para el diagnóstico oportuno de Mycobacterium tu-berculosis complex. Sin embargo, es esencial considerar las diversas condiciones de las muestras y pacientes para optimizar la precisión diagnóstica

Introduction: Implementing an appropriate and efficient diagnostic method is cru-cial for the early detection of tuberculosis. This not only allows for effective control of the disease to prevent its transmission and progression to more severe stages but also prevents the development of drug resistance in patients.Objective: To evaluate the utility of the GeneXpert MTB/RIF molecular test in diag-nosing Mycobacterium tuberculosis complex, compared to sputum smear micros-copy, using culture as the reference. Material and Methods: A descriptive, observational, and non-experimental cross-sectional study was conducted, including 253 samples from patients of both sexes and various age ranges, which were assessed using sputum smear micros-copy, GeneXpert MTB/RIF, and culture. The study focused on samples processed at a Quito ́s Public Hospital during the period from January 2021 to May 2022.Results: The GeneXpert MTB/RIF molecular test showed a sensitivity of 94.7% and a specificity of 93.9% for the diagnosis of Mycobacterium tuberculosis com-plex. Additionally, a case of resistance to rifampicin was identified.Conclusion: This study confirms the effectiveness of the GeneXpert MTB/RIF mo-lecular test over sputum smear microscopy for the timely diagnosis of tuberculosis. However, it is essential to consider the diverse conditions of the samples and pa-tients to optimize diagnostic accuracy

Rapid and accurate identification and differentiation of Mycobacterium tuberculosis and non-tuberculous mycobacteria using PCR kits available in a high-burden setting.

Infections caused by mycobacteria, including Mycobacterium tuberculosis complex (MTBC) and non-tuberculous mycobacteria (NTM), are a major public health issue worldwide. An accurate diagnosis of mycobacterial species is a challenge for surveillance and treatment, particularly in high-burden settings usually associated with low- and middle-income countries. In this study, we analyzed the clinical performance of two commercial PCR kits designed for the identification and differentiation of MTBC and NTM, available in a high-burden setting such as Ecuador. A total of 109 mycobacteria isolates were included in the study, 59 of which were previously characterized as M. tuberculosis and the other 59 as NTM. Both kits displayed great clinical performance for the identification of M. tuberculosis, with 100% sensitivity. On the other hand, for NTM, one of the kits displayed a good clinical performance with a sensitivity of 94.9% (CI 95%: 89-100%), while the second kit had a reduced sensitivity of 77.1% (CI 95%: 65-89%). In conclusion, one of the kits is a fast and reliable tool for the identification and discrimination of MTBC and NTM from clinical isolates.

Bactericidal Permeability-Increasing Protein (BPI) Inhibits Mycobacterium tuberculosis Growth.

Bactericidal permeability-increasing protein (BPI) is a multifunctional cationic protein produced by neutrophils, eosinophils, fibroblasts, and macrophages with antibacterial anti-inflammatory properties. In the context of Gram-negative infection, BPI kills bacteria, neutralizes the endotoxic activity of lipopolysaccharides (LPSs), and, thus, avoids immune hyperactivation. Interestingly, BPI increases in patients with Gram-positive meningitis, interacts with lipopeptides and lipoteichoic acids of Gram-positive bacteria, and significantly enhances the immune response in peripheral blood mononuclear cells. We evaluated the antimycobacterial and immunoregulatory properties of BPI in human macrophages infected with Mycobacterium tuberculosis. Our results showed that recombinant BPI entered macrophages, significantly reduced the intracellular growth of M. tuberculosis, and inhibited the production of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-α). Furthermore, BPI decreased bacterial growth directly in vitro. These data suggest that BPI has direct and indirect bactericidal effects inhibiting bacterial growth and potentiating the immune response in human macrophages and support that this new protein's broad-spectrum antibacterial activity has the potential for fighting tuberculosis.