A single upstream mutation of whiB7 underlies amikacin and clarithromycin resistance in Mycobacterium abscessus.

Aims: We aimed to investigate the molecular mechanisms underlying the survival of Mycobacterium abscessus when faced with antibiotic combination therapy. By conducting evolution experiments and whole-genome sequencing (WGS), we sought to identify genetic variants associated with stress response mechanisms, with a particular focus on drug survival and resistance.

Methods And Results: We conducted evolution experiments on M.

Transcriptomic profile of the most successful strain in Aragon, the MtZ strain, during exponential and stationary growth phases.

Aragon Community suffered, during the first years of the beginning of this century, a large outbreak caused by the MtZ strain, producing more than 240 cases to date. MtZ strain and the outbreak have been previously studied from an epidemiological and molecular point of view. In this work, we analyzed the transcriptomic profile of the strain for better understanding of its success among our population.

Targeted Chromosomal Barcoding Establishes Direct Genotype-Phenotype Associations for Antibiotic Resistance in Mycobacterium abscessus.

A bedaquiline-resistant Mycobacterium abscessus isolate was sequenced, and a candidate mutation in the gene was identified as responsible for the antibiotic resistance phenotype. To establish a direct genotype-phenotype relationship of this mutation which results in a Asp-to-Ala change at position 29 (D29A), we developed a recombineering-based method consisting of the specific replacement of the desired mutation in the bacterial chromosome. As surrogate bacteria, we used two M.

A microfluidic-based analysis of 3D macrophage migration after stimulation by Mycobacterium, Salmonella and Escherichia.

Macrophages play an essential role in the process of recognition and containment of microbial infections. These immune cells are recruited to infectious sites to reach and phagocytose pathogens. Specifically, in this article, bacteria from the genus Mycobacterium, Salmonella and Escherichia, were selected to study the directional macrophage movement towards different bacterial fractions.

The MtZ Strain: Molecular Characteristics and Outbreak Investigation of the Most Successful Strain in Aragon Using Whole-Genome Sequencing.

Since 2004, a tuberculosis surveillance protocol has been carried out in Aragon, thereby managing to detect all tuberculosis outbreaks that take place in the community. The largest outbreak was caused by a strain named (MtZ), causing 242 cases as of 2020. The main objective of this work was to analyze this outbreak and the molecular characteristics of this successful strain that could be related to its greater transmission.

The PhoPR virulence system regulates expression of the universal second messenger c-di-AMP and impacts vaccine safety and efficacy.

Cyclic (di)nucleotides act as universal second messengers endogenously produced by several pathogens. Specifically, the roles of c-di-AMP in immunity and virulence have been largely explored, although its contribution to the safety and efficacy of live tuberculosis vaccines is less understood. In this study, we demonstrate that the synthesis of c-di-AMP is negatively regulated by the PhoPR virulence system.

Engineering a new vaccine platform for heterologous antigen delivery in live-attenuated .

Live vaccines are attractive vehicles for antigen delivery as a strategy to immunize against heterologous pathogens. The live vaccine MTBVAC is based on rational attenuation of with the objective of improving BCG protection against pulmonary tuberculosis. However, the development of recombinant mycobacteria as antigen-presenting microorganisms has been hindered due to their fastidious genetic manipulation.

MTBVAC, a live TB vaccine poised to initiate efficacy trials 100 years after BCG.

At its 100th birthday of its first administration to a newborn, BCG has been (and continues being) an inspiration for the construction and development of hundreds of new TB vaccine candidates in the last two and a half decades. Today, 14 candidates are in clinical development inside the global TB vaccine pipeline. MTBVAC is one of these candidates.

BCG vaccination improves DTaP immune responses in mice and is associated with lower pertussis incidence in ecological epidemiological studies.

Background: The Bacillus Calmette-Guérin (BCG), the only vaccine against tuberculosis (TB) currently in use, has shown beneficial effects against unrelated infections and to enhance immune responses to vaccines. However, there is little evidence regarding the influence of BCG vaccination on pertussis.

Methods: Here, we studied the ability of BCG to improve the immune responses to diphtheria, tetanus, and acellular (DTaP) or whole-cell pertussis (DTwP) vaccination in a mouse model.

Microfluidic devices for studying bacterial taxis, drug testing and biofilm formation.

Some bacteria have coevolved to establish symbiotic or pathogenic relationships with plants, animals or humans. With human association, the bacteria can cause a variety of diseases. Thus, understanding bacterial phenotypes at the single-cell level is essential to develop beneficial applications.

Independent genomic polymorphisms in the PknH serine threonine kinase locus during evolution of the Mycobacterium tuberculosis Complex affect virulence and host preference.

Species belonging to the Mycobacterium tuberculosis Complex (MTBC) show more than 99% genetic identity but exhibit distinct host preference and virulence. The molecular genetic changes that underly host specificity and infection phenotype within MTBC members have not been fully elucidated. Here, we analysed RD900 genomic region across MTBC members using whole genome sequences from 60 different MTBC strains so as to determine its role in the context of MTBC evolutionary history.

Live attenuated TB vaccines representing the three modern Mycobacterium tuberculosis lineages reveal that the Euro-American genetic background confers optimal vaccine potential.

Background: Human tuberculosis (TB) is caused by a plethora of Mycobacterium tuberculosis complex (MTBC) strains belonging to seven phylogenetic branches. Lineages 2, 3 and 4 are considered "modern" branches of the MTBC responsible for the majority of worldwide TB. Since the current BCG vaccine confers variable protection against pulmonary TB, new candidates are investigated.

Live-attenuated Mycobacterium tuberculosis vaccine MTBVAC versus BCG in adults and neonates: a randomised controlled, double-blind dose-escalation trial.

Background: Infants are a key target population for new tuberculosis vaccines. We assessed the safety and immunogenicity of the live-attenuated Mycobacterium tuberculosis vaccine candidate MTBVAC in adults and infants in a region where transmission of tuberculosis is very high.

Methods: We did a randomised, double-blind, BCG-controlled, dose-escalation trial at the South African Tuberculosis Vaccine Initiative site near Cape Town, South Africa.

Comparative Metabolomics between and the MTBVAC Vaccine Candidate.

MTBVAC is a live attenuated vaccine constructed by genetic deletions in the and virulence genes. The MTBVAC vaccine is currently in phase 2 clinical trials with newborns and adults in South Africa, one of the countries with the highest incidence. Although MTBVAC has been extensively characterized by genomics, transcriptomics, lipidomics, and proteomics, its metabolomic profile is yet unknown.

MTBVAC-Based TB-HIV Vaccine Is Safe, Elicits HIV-T Cell Responses, and Protects against in Mice.

The tuberculosis (TB) vaccine MTBVAC is the only live-attenuated ()-based vaccine in clinical development, and it confers superior protection in different animal models compared to the current vaccine, BCG ( bacillus Calmette-Guérin). With the aim of using MTBVAC as a vector for a dual TB-HIV vaccine, we constructed the recombinant MTBVAC.HIVA strain.

New insights into the transposition mechanisms of IS6110 and its dynamic distribution between Mycobacterium tuberculosis Complex lineages.

The insertion Sequence IS6110, only present in the pathogens of the Mycobacterium tuberculosis Complex (MTBC), has been the gold-standard epidemiological marker for TB for more than 25 years, but biological implications of IS6110 transposition during MTBC adaptation to humans remain elusive. By studying 2,236 clinical isolates typed by IS6110-RFLP and covering the MTBC, we remarked a lineage-specific content of IS6110 being higher in modern globally distributed strains. Once observed the IS6110 distribution in the MTBC, we selected representative isolates and found a correlation between the normalized expression of IS6110 and its abundance in MTBC chromosomes.

Vaccination against tuberculosis.

BCG (Bacille Calmette-Guérin) vaccination is included in the immunization schedule for tuberculosis endemic countries with a global coverage at birth close to 90% worldwide. BCG was attenuated from Mycobacterium bovis almost a century ago, and provides a strong protection against disseminated forms of the disease, though very limited against pulmonary forms of tuberculosis, responsible for transmission. Novel prophylactic tuberculosis vaccines are in clinical development either to replace BCG or to improve its protection against respiratory forms of the disease.

MTBVAC: Attenuating the Human Pathogen of Tuberculosis (TB) Toward a Promising Vaccine against the TB Epidemic.

Bacille Calmette-Guérin (BCG) is a live-attenuated strain of developed a century ago by repeated subculture. It remains the only vaccine against tuberculosis (TB) in use today, and it offers variable protection against the respiratory forms of TB responsible for transmission. The principal genetic basis for BCG attenuation is the loss of the region of difference 1 (RD1) that includes the genes codifying for production and export of the major virulence factor ESAT6.

Breaking Transmission with Vaccines: The Case of Tuberculosis.

Members of the complex (MTBC) have evolved causing tuberculosis (TB) in different mammalian hosts. MTBC ecotypes have adapted to diverse animal species, with being the most common cause of TB in livestock. Cattle-to-human transmission of through ingestion of raw milk was common before introduction of the pasteurization process.

Reactogenicity to major tuberculosis antigens absent in BCG is linked to improved protection against Mycobacterium tuberculosis.

MTBVAC is a live-attenuated Mycobacterium tuberculosis vaccine, currently under clinical development, that contains the major antigens ESAT6 and CFP10. These antigens are absent from the current tuberculosis vaccine, BCG. Here we compare the protection induced by BCG and MTBVAC in several mouse strains that naturally express different MHC haplotypes differentially recognizing ESAT6 and CFP10.

MTBVAC from discovery to clinical trials in tuberculosis-endemic countries.

BCG remains the only vaccine against tuberculosis (TB) in use today and despite its impressive global coverage, the nature of BCG protection against the pulmonary forms of TB remains subject to ongoing debate. Because of the limitations of BCG, novel TB vaccine candidates have been developed and several have reached the clinical pipeline. One of these candidates is MTBVAC, the first and only TB vaccine in the clinical pipeline to date based on live-attenuated Mycobacterium tuberculosis that has successfully entered clinical evaluation, a historic milestone in human vaccinology.

Mycobacterium tuberculosis Complex Exhibits Lineage-Specific Variations Affecting Protein Ductility and Epitope Recognition.

The advent of whole-genome sequencing has provided an unprecedented detail about the evolution and genetic significance of species-specific variations across the whole Mycobacterium tuberculosis Complex. However, little attention has been focused on understanding the functional roles of these variations in the protein coding sequences. In this work, we compare the coding sequences from 74 sequenced mycobacterial species including M.