Advancing Translational Science for Pulmonary Nontuberculous Mycobacterial Infections. A Road Map for Research.
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ABSTRACT:
SUBMITTER: Daniel-Wayman S
PROVIDER: S-EPMC6467310 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Perforin-2 is a highly conserved pore-forming protein encoded by macrophage expressed gene 1 (MPEG1). A number of studies have shown that Perforin-2-deficient mice are unable to survive following a bacterial challenge that is nonlethal in WT mice. There is also recent evidence that Mpeg1+/- heterozygous mice display an intermediate killing ability compared with Mpeg1 WT and Mpeg1-/- mice. Despite these in vivo findings, to date, no perforin-2 deficiencies have been associated with human disease. Here, we report four patients with persistent nontuberculous mycobacterial infection who had heterozygous MPEG1 mutations. In vitro, neutrophils, macrophages, and B cells from these patients were unable to kill Mycobacterium avium as efficiently as normal controls. CRISPR mutagenesis validated the deleterious antibacterial activity of these mutations. These data suggest that perforin-2 haploinsufficiency may contribute to human susceptibility to infections with intracellular bacteria.
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Project description:The diagnosis of pulmonary non-tuberculous mycobacterial disease (pNTM) is dependent on the isolation of NTM in culture, which is prone to overgrowth and contamination and may not capture the diversity of mycobacteria present, including rare or unidentified species. This study aimed to develop a culture independent method of detecting and identifying mycobacteria from sputum samples using partial sequencing of the hsp65 gene. DNA was extracted from sputum samples from subjects with pNTM and disease controls. Multiplexed partial sequencing of the hsp65 gene was performed using the Illumina MiSeq and custom primers. A reference database of hsp65 sequences was created for taxonomy assignment. Sequencing results were obtained from 42 subjects (31 cases, 11 controls). Mycobacterial sequences were identified in all subjects. In 90.5% of samples more than one species was found (median 5.5). The species isolated in culture was detected by sequencing in 81% of subjects and was the most abundant species in 62%. The sequencing of NTM from clinical samples reveals a far greater diversity than conventional culture and suggests NTM are present as communities rather than a single species. NTM were found to be present even in the absence of isolation in culture or clinical disease.
| S-EPMC6289444 | biostudies-literature
Project description:Nontuberculous mycobacteria (NTM) are environmental organisms associated with pulmonary disease without person-to-person transmission. Although genetic causes of disseminated NTM infection are well characterized, genetic causes for most human susceptibility to pulmonary NTM infection have not been determined.Family histories for relevant disease characteristics were obtained as part of an ongoing natural history study. Six families were identified in which at least two blood relatives had pulmonary NTM. A systematic review of medical records extracted data relevant to pulmonary infection and baseline demographics. Data were reconfirmed by telephone interviews.Familial clustering of pulmonary NTM was proven in six families. Four of the families were white, and the majority of affected individuals were women. The average age at diagnosis was 56.4 +/- 10.7 years, the average height was 167.5 +/- 8.7 cm, and the mean BMI was 22.0 +/- 2.98 kg/m(2). Scoliosis was present in 31%. Five of 12 patients had cystic fibrosis transmembrane conductance regulator gene variations, but none had classic cystic fibrosis. Infections were caused by both slow and rapid growing mycobacteria, including Mycobacterium avium, Mycobacterium intracellulare, Mycobacterium kansasii, Mycobacterium abscessus, and Mycobacterium massiliense. Family members were typically infected with different species of NTM.We identified six familial clusters of pulmonary NTM infection, suggesting that there are genetic factors contributing to host susceptibility to pulmonary infection with NTM among some individuals with nodular bronchiectatic disease.
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Project description:Infection secondary to rapidly growing mycobacteria (RGM) is associated with significant morbidity and mortality, especially in individuals with underlying structural lung disease or immune compromise. Such infections, particularly those caused by the Mycobacterium abscessus group, are challenging to treat due to high virulence, antibiotic resistance, and the lack of effective and tolerable therapies. Although novel antimycobacterials are under development, clofazimine-a drug historically administered as part of multidrug therapy regimens for Mycobacterium leprae-holds promise as a chemotherapeutic for the treatment of RGM. The history, pharmacologic properties of clofazimine, as well as in vitro and in vivo studies against RGM are described here and highlight a potential new niche for an old drug.
| S-EPMC6124512 | biostudies-other
Project description:Nontuberculous mycobacterial (NTM) pulmonary infections are a global health concern and a significant contributor to lung disease. Systemic therapies of a cocktail of antibiotics administered over a long period often lead to adverse reactions and/or treatment failure. NTM pathogens, such as Mycobacterium abscessus (Mabs), are notoriously difficult to treat due to resistance to many traditional antibiotics. However, the antibiotic tigecycline has demonstrated efficacy in vitro and in vivo against Mabs strains varying in drug susceptibility. Tigecycline exhibits instability in aqueous medium, posing delivery challenges, and has caused severe adverse gastrointestinal effects following intravenous administration, requiring treatment discontinuation. To mitigate both of these concerns, inhalation therapies using dry powder aerosols are proposed as an alternative administration route and means of delivery. Tigecycline dry powder formulations were prepared, characterized, and optimized to develop a therapeutic aerosol with low moisture, high dispersibility, and a large fraction of particles in the respirable size range (1-5 μm). The addition of lactose, leucine, and phosphate buffer salts was investigated to achieve additional stability, dispersibility, and tolerability. Preliminary delivery of the dry powders to Mabs-infected mice for 30 min per day over 7 d demonstrated a 0.91-log (87.7%) decrease in lung bacterial burden.
| S-EPMC10191180 | biostudies-literature
Project description:Increasing recognition of the complexity of environmental problems and the need to understand social processes and human values is leading environmental management agencies in many nations, including the USA, to integrate more research from the social sciences through the inclusion of social scientists on interdisciplinary teams. For this study we conducted focus groups at three research laboratories within the U.S. Environmental Protection Agency's Office of Research and Development to better understand how inclusion of social sciences influenced the research process and outcomes, and the barriers to and facilitators of integration. The focus groups identified effects on the research process including improved problem framing, the introduction of new methodologies, and greater stakeholder and public inclusion, while research outcomes included the inclusion or refinement of social and environmental perspectives and systems thinking, increased translatability of research, and new partnerships. Barriers identified included lack of familiarity with social sciences which affected perceptions of social sciences and organizational capacity to absorb and apply social science expertise. Facilitators included receptivity of team members, intentional communication strategies, and project structures and organizational commitment that support interdisciplinary work. Finding a key barrier to be lack of clarity about the different roles social sciences play in translational research, we present a conceptual model defining the roles and contributions of social scientists that clarifies the distinction between "integration" of social sciences in research and "application" of skills and knowledge from the social sciences which play distinct but equally important roles in translational research approaches and solutions-driven research. These insights on the ways social sciences contribute to translational research efforts advance integration of social and natural sciences in environmental science research, particularly in applied contexts.
| S-EPMC10031653 | biostudies-literature
Project description: Not available
| S-EPMC4880076 | biostudies-literature
Project description:RationaleThe clinical features of patients infected with pulmonary nontuberculous mycobacteria (PNTM) are well described, but the genetic components of infection susceptibility are not.ObjectivesTo examine genetic variants in patients with PNTM, their unaffected family members, and a control group.MethodsWhole-exome sequencing was done on 69 white patients with PNTM and 18 of their white unaffected family members. We performed a candidate gene analysis using immune, cystic fibrosis transmembrance conductance regulator (CFTR), cilia, and connective tissue gene sets. The numbers of patients, family members, and control subjects with variants in each category were compared, as was the average number of variants per person.Measurements and main resultsA significantly higher number of patients with PNTM than the other subjects had low-frequency, protein-affecting variants in immune, CFTR, cilia, and connective tissue categories (35, 26, 90, and 90%, respectively). Patients with PNTM also had significantly more cilia and connective tissue variants per person than did control subjects (2.47 and 2.55 compared with 1.38 and 1.40, respectively; P = 1.4 × 10(-6) and P = 2.7 × 10(-8), respectively). Patients with PNTM had an average of 5.26 variants across all categories (1.98 in control subjects; P = 2.8 × 10(-17)), and they were more likely than control subjects to have variants in multiple categories. We observed similar results for family members without PNTM infection, with the exception of the immune category.ConclusionsPatients with PNTM have more low-frequency, protein-affecting variants in immune, CFTR, cilia, and connective tissue genes than their unaffected family members and control subjects. We propose that PNTM infection is a multigenic disease in which combinations of variants across gene categories, plus environmental exposures, increase susceptibility to the infection.
| S-EPMC4595692 | biostudies-literature
Project description:The clinical relevance of newly described nontuberculous mycobacteria is often unclear. We report a case of pulmonary infection caused by Mycobacterium hassiacum in an immunocompetent patient in Austria who had chronic obstructive pulmonary disease. Antimicrobial drug susceptibility testing showed low MICs for macrolides, aminoglycosides, fluoroquinolones, tetracyclines, imipenem, and linezolid.
| S-EPMC7588525 | biostudies-literature
Project description:BackgroundOwing to the unsatisfactory results of antibiotic treatment alone, surgical resection is currently considered as adjunctive therapy in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD). However, reports regarding the outcomes of surgery vary considerably by institution. Here, we investigated the surgical outcomes and risk factors associated with unfavorable outcomes after surgery.MethodsWe analyzed patients with NTM-PD who underwent pulmonary resection at Seoul National University Hospital between January 1, 2006, and December 31, 2020, and assessed the types of surgical procedures, complications, and long-term outcomes. Multivariate logistic regression analysis was used to identify the risk factors associated with treatment refractoriness or recurrence after surgery.ResultsAmong 67 patients who underwent surgery during the study period, the most common indication for surgery was persistent culture positivity despite rigorous medical treatment (80.6%), followed by longstanding cavitary lesions or radiographic aggravation (10.4%) and massive hemoptysis (4.5%). Among 53 patients with positive mycobacterial cultures at the time of surgery, 38 (71.7%) achieved initial negative culture conversion, 9 (17.0%) of whom experienced recurrence. Nine (13.4%) patients experienced postoperative complications, which were managed without lasting morbidity and mortality. Female sex (adjusted odds ratio [aOR] 6.63; 95% confidence interval [CI] 1.04-42.4; P = .046), preoperative positive mycobacterial culture (aOR 5.87; 95 %CI 1.04-33.08; P = .045), and residual lesions (aOR 6.86; 95 %CI 1.49-31.56; P = .013) were associated with refractoriness or recurrence.ConclusionsPulmonary resection is a reasonable treatment modality for patients with refractory NTM-PD or major complications such as massive hemoptysis. The potential risk factors associated with unfavorable outcomes included female sex, preoperative positive mycobacterial culture, and residual lesions after surgery.
| S-EPMC8496107 | biostudies-literature