Granulysin Antimicrobial Activity Promotes Dormancy in Mycobacterium tuberculosis.

Human tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) remains a global public health threat. Granulomas constitute a hallmark of TB pathogenesis that can clear, contain, or exacerbate an infection. Containment is exploited by Mtb as a hideout to persist in a dormant, antibiotic-tolerant state, only to resuscitate upon immunosuppression.

Linking genetic and phenotypic bedaquiline resistance in Mycobacterium tuberculosis strains from Georgia.

Introduction: Resistance to bedaquiline - a novel, promising medication against tuberculosis (TB), is already emerging, and uncertainties regarding the role of the different resistance-conferring mutations complicate the development of molecular diagnostic tools for detecting resistance. Mutations in the three genes atpE, pepQ, and Rv0678 have been associated with increased minimum inhibitory concentrations (MICs) to bedaquiline in Mycobacterium tuberculosis (Mtb). Here, we studied the effect of known and novel mutations in these genes on the phenotypic susceptibility to bedaquiline in Mtb isolates from patients with drug-resistant TB in the country of Georgia.

Genome-to-genome analysis reveals associations between human and mycobacterial genetic variation in tuberculosis patients from Tanzania.

The risk and prognosis of tuberculosis (TB) are influenced by a complex interplay between human and bacterial genetic factors. While previous genomic studies have largely examined human and bacterial genomes separately, we adopted an integrated approach to uncover host-pathogen interactions. We leveraged paired human and Mycobacterium tuberculosis (M.

Gene conversion and duplication contribute to genetic variation in an outbreak of .

Repeats are the most diverse and dynamic but also the least well-understood component of microbial genomes. For all we know, repeat-associated mutations such as duplications, deletions, inversions and gene conversion might be as common as point mutations, but because of short-read myopia and methodological bias, they have received much less attention. Long-read DNA sequencing opens the perspective of resolving repeats and systematically investigating the mutations they induce.

Mycobacteria beyond disease.

Mycobacteria have coevolved with humans over millennia, leaving profound imprints on our immune systems. Beyond active disease, their exposure may exert immunomodulatory effects, including allergy modulation and heterologous protection against infections. This forum article explores these potentially mutualistic interactions, highlighting their potential for novel therapies and public health strategies.

Soluble immune mediators orchestrate protective granulomatous responses across complex lineages.

The members of the complex (MTBC) causing human tuberculosis comprise 10 phylogenetic lineages that differ in their geographical distribution. The human consequences of this phylogenetic diversity remain poorly understood. Here, we assessed the phenotypic properties at the host-pathogen interface of 14 clinical strains representing five major MTBC lineages.

Ecology, global diversity and evolutionary mechanisms in the Mycobacterium tuberculosis complex.

With the COVID-19 pandemic receding, tuberculosis (TB) is again the number one cause of human death to a single infectious agent. TB is caused by bacteria that belong to the Mycobacterium tuberculosis complex (MTBC). Recent advances in genome sequencing have provided new insights into the ecology and evolution of the MTBC.

Onset of infectiousness explains differences in transmissibility across Mycobacterium tuberculosis lineages.

Mycobacterium tuberculosis complex (MTBC) lineages show substantial variability in virulence, but the epidemiological consequences of this variability have not been studied in detail. Here, we aimed for a lineage-specific epidemiological characterization by applying phylodynamic models to genomic data from different countries, representing the most abundant MTBC lineages. Our results suggest that all lineages are associated with similar durations and levels of infectiousness, resulting in similar reproductive numbers.

Drug-induced differential culturability in diverse strains of Mycobacterium tuberculosis.

Under stress, bacteria display selective growth propensities on solid and liquid media. For Mycobacterium tuberculosis (Mtb), differentially culturable bacteria have been found in tuberculosis (TB) patient sputa. We hypothesized that antibiotic treatment can induce selective culturability in Mtb.

Diagnostic accuracy of a sequence-specific -DNA hybridization assay in urine: a case-control study including subclinical TB cases.

Unlabelled: Tuberculosis (TB) caused by () remains one of the deadliest infectious diseases globally. Timely diagnosis is a key step in the management of TB patients and in the prevention of further transmission events. Current diagnostic tools are limited in these regards.

HIV co-infection is associated with reduced Mycobacterium tuberculosis transmissibility in sub-Saharan Africa.

Persons living with HIV are known to be at increased risk of developing tuberculosis (TB) disease upon infection with Mycobacterium tuberculosis (Mtb). However, it has remained unclear how HIV co-infection affects subsequent Mtb transmission from these patients. Here, we customized a Bayesian phylodynamic framework to estimate the effects of HIV co-infection on the Mtb transmission dynamics from sequence data.

Bacterial diversity dominates variable macrophage responses of tuberculosis patients in Tanzania.

The Mycobacterium tuberculosis complex (MTBC) comprises nine human-adapted lineages that differ in their geographical distribution. Local adaptation of specific MTBC genotypes to the respective human host population has been invoked in this context. We aimed to assess if bacterial genetics governs MTBC pathogenesis or if local co-adaptation translates into differential susceptibility of human macrophages to infection by different MTBC genotypes.

Key Contributions by the Swiss Tropical and Public Health Institute Towards New and Better Drugs for Tropical Diseases.

Thanks to its expertise in clinical research, epidemiology, infectious diseases, microbiology, parasitology, public health, translational research and tropical medicine, coupled with deeply rooted partnerships with institutions in low- and middle-income countries (LMICs), the Swiss Tropical and Public Health Institute (Swiss TPH) has been a key contributor in many drug research and development consortia involving academia, pharma and product development partnerships. Our know-how of the maintenance of parasites and their life-cycles in the laboratory, plus our strong ties to research centres and disease control programme managers in LMICs with access to field sites and laboratories, have enabled systems for drug efficacy testing in vitro and in vivo, clinical research, and modelling to support the experimental approaches. Thus, Swiss TPH has made fundamental contributions towards the development of new drugs - and the better use of old drugs - for neglected tropical diseases and infectious diseases of poverty, such as Buruli ulcer, Chagas disease, food-borne trematodiasis (e.

Bedaquiline resistance in patients with drug-resistant tuberculosis in Cape Town, South Africa: a retrospective longitudinal cohort study.

Background: Bedaquiline is a life-saving tuberculosis drug undergoing global scale-up. People at risk of weak tuberculosis drug regimens are a priority for novel drug access despite the potential source of Mycobacterium tuberculosis-resistant strains. We aimed to characterise bedaquiline resistance in individuals who had sustained culture positivity during bedaquiline-based treatment.

Macrophage susceptibility to infection by Ghanaian complex lineages 4 and 5 varies with self-reported ethnicity.

Background: The epidemiology of complex (MTBC) lineage 5 (L5) infections in Ghana revealed a significantly increased prevalence in Ewes compared to other self-reported ethnic groups. In that context, we sought to investigate the early phase of tuberculosis (TB) infection using infection of macrophages derived from the blood of Ewe and Akan ethnic group volunteers with MTBC L4 and L5 strains.

Methods: The study participants consisted of 16 controls, among which self-reported Akan and Ewe ethnicity was equally represented, as well as 20 cured TB cases consisting of 11 Akans and 9 Ewes.

Lack of methoxy-mycolates characterizes the geographically restricted lineage 7 of complex.

Lineage 7 (L7) emerged in the phylogeny of the complex (MTBC) subsequent to the branching of 'ancient' lineage 1 and prior to the Eurasian dispersal of 'modern' lineages 2, 3 and 4. In contrast to the major MTBC lineages, the current epidemiology suggests that prevalence of L7 is highly confined to the Ethiopian population, or when identified outside of Ethiopia, it has mainly been in patients of Ethiopian origin. To search for microbiological factors that may contribute to its restricted distribution, we compared the genome of L7 to the genomes of globally dispersed MTBC lineages.

The relative transmission fitness of multidrug-resistant Mycobacterium tuberculosis in a drug resistance hotspot.

Multidrug-resistant tuberculosis (MDR-TB) is among the most frequent causes of death due to antimicrobial resistance. Although only 3% of global TB cases are MDR, geographical hotspots with up to 40% of MDR-TB have been observed in countries of the former Soviet Union. While the quality of TB control and patient-related factors are known contributors to such hotspots, the role of the pathogen remains unclear.

Back-to-Africa introductions of Mycobacterium tuberculosis as the main cause of tuberculosis in Dar es Salaam, Tanzania.

In settings with high tuberculosis (TB) endemicity, distinct genotypes of the Mycobacterium tuberculosis complex (MTBC) often differ in prevalence. However, the factors leading to these differences remain poorly understood. Here we studied the MTBC population in Dar es Salaam, Tanzania over a six-year period, using 1,082 unique patient-derived MTBC whole-genome sequences (WGS) and associated clinical data.

Clinical implications of molecular drug resistance testing for Mycobacterium tuberculosis: a 2023 TBnet/RESIST-TB consensus statement.

Drug-resistant tuberculosis is a substantial health-care concern worldwide. Despite culture-based methods being considered the gold standard for drug susceptibility testing, molecular methods provide rapid information about the Mycobacterium tuberculosis mutations associated with resistance to anti-tuberculosis drugs. This consensus document was developed on the basis of a comprehensive literature search, by the TBnet and RESIST-TB networks, about reporting standards for the clinical use of molecular drug susceptibility testing.