Inhaled nitric oxide (iNO), long used as a selective pulmonary vasodilator, has demonstrated potential antimicrobial and antiviral properties when administered at high concentrations (> 20 parts per million, ppm). While definitive evidence is still lacking, this narrative review synthesizes the emerging clinical and mechanistic properties supporting high-dose iNO as a potential therapeutic strategy for lower respiratory tract infections, including drug-resistant bacterial pneumonias, COVID-19, nontuberculous mycobacteria, and bronchiolitis. We summarize safety data from laboratory studies, Phase I trials, clinical findings from 27 predominantly early-phase studies, and highlight its as both hospital-based and home-based therapy. High-dose iNO acts through multiple pathways, including direct microbial killing, biofilm disruption, immune modulation, and mucociliary enhancement, and holds promise in addressing unmet needs in respiratory infection management. We also propose a roadmap for future research to optimize dosing, delivery, and efficacy endpoints in well-defined patient populations. High-dose inhaled nitric oxide is a potential antimicrobial therapy with broad-spectrum activity against bacteria, viruses, fungi, and parasites, and has been safely administered in diverse clinical contexts from ICU to outpatient care. This review summarizes translational and early clinical data and outlines a roadmap for future trials needed to define safety, efficacy, and optimal use in drug-resistant lung infections and acute respiratory failure.

Purpose Extrapulmonary nontuberculous mycobacterial (EPNTM) infections of bone, joint, and soft tissue are difficult to treat and lack species-specific outcome data. We sought to describe antimicrobial regimens and surgical management by Mycobacterium spp. and to identify predictors of a clinical cure within 12 months in this adult cohort with EPNTM. Methods We conducted a multicentre retrospective cohort study across five tertiary hospitals in Australia and New Zealand 2014–2020. Adults with culture-confirmed EPNTM infection from sterile or intraoperative specimens were included. Primary outcome was clinical cure at 12 months. Secondary outcomes included relapse, drug toxicity and host factors. Results Among 107 patients, six species groups were identified, most commonly M. abscessus complex (n = 26, 25%), Mycobacterium marinum (n = 25, 24%), and M. fortuitum complex (n = 24, 23%). Clinical cure within 12 months differed significantly by species, with high cure proportions for M. abscessus (n = 22, 92%) in surgically accessible infections and lower cure rates for M. chelonae (n = 6, 60%) and mixed slow growing mycobacteria (n = 4, 36%). Younger age (median 47 vs 60 years, p = 0.006) and Mycobacterium spp . was associated with cure whereas antimicrobial class and surgical intervention were not. Of antibiotic classes used, only macrolide duration was associated with cure. Relapse was uncommon (8%) and occurred predominantly in immunosuppressed patients. Conclusions This first multicentre Australasian cohort demonstrates substantial species-specific variation in outcomes of EPNTM osteoarticular and soft-tissue infections. This study highlights the need for species-specific management pathways and prospective studies.

BACKGROUND:Bronchiectasis is a chronic respiratory condition involving a cycle of impaired mucociliary clearance, chronic infections, inflammation, and progressive airway destruction, leading to persistent cough with sputum production, dyspnea, and fatigue. Without appropriate management, patients can experience increased exacerbations, reduced quality of life, declining lung function, and increased mortality risk. Variability exists in clinical practice regarding treatment selection, highlighting the need for evidence-based guidance to optimize patient outcomes and standardize care delivery across health care settings. METHODS:An expert panel developed 8 population, intervention, comparator, and outcome (PICO)-based questions addressing treatment of bronchiectasis in adults and conducted a systematic review. The panel applied the Grading of Recommendations, Assessment, Development, and Evaluations approach to assess the certainty of evidence and to formulate and grade recommendations. A modified Delphi technique was used to reach consensus on the recommendations. RESULTS:Based on 47 studies, the panel developed 13 evidence-based recommendations addressing key management domains, including antibiotic treatment for acute exacerbations, duration and route of antibiotic therapy, long-term suppressive antibiotic and anti-inflammatory therapies, airway clearance strategies, management of hemoptysis and consideration of surgical resection in selected patients. CONCLUSION:All recommendations are conditional, primarily based on low-certainty evidence. Bronchiectasis research should aim to address many of the uncertainties in management, and priorities are identified within each PICO question. Accurate phenotyping and endotyping may help guide therapeutic decision-making and risk stratification. Treatment interventions must consider potential treatment burdens, including cost, and impact on quality of life. Finally, shared decision-making with patients utilizing a multidisciplinary approach is paramount.

In vitro antibiotic testing is important for guiding therapy and drug development. Current methods are focused on growth inhibition in bulk bacterial populations but often fail to accurately predict treatment responses. Here we introduce Antimicrobial Single-Cell Testing (ASCT), a large-scale live-cell imaging approach that quantifies bacterial killing in real time at single-cell resolution. By tracking over 140 million mycobacteria and analysing ~20,000 time–kill curves, we identify key determinants of antibiotic killing and its clinical relevance. For Mycobacterium tuberculosis, we found that drug-specific killing dynamics in starved bacteria, rather than growth inhibition or killing of growing cells, predict regimen efficacy in mice and humans. Extending this approach to Mycobacterium abscessus and comparing 405 bacterial strains, we show that antibiotic killing is also a genetically encoded bacterial trait (drug tolerance). We demonstrate that tolerance patterns cluster by antibiotic targets, identify a phage protein that modulates antibiotic killing, and show that strain-specific killing dynamics are associated with individual patient outcomes independent of drug resistance. Together, these findings establish a framework that reveals how drug properties and bacterial diversity shape treatment responses, offering a path to more effective and personalized therapies. Via high-throughput imaging and tracking over 140 million single mycobacteria, the authors show that drug- and strain-specific killing predict treatment outcomes, with potential to improve drug development and personalized therapy.

Introduction Managing patients with nontuberculous mycobacterial pulmonary disease (NTM-PD) unresponsive to guideline-based therapy remains challenging due to limited treatment options and complex disease progression. This study systematically reviewed existing literature on management strategies and emerging therapeutic approaches for refractory NTM-PD.Methods We systematically reviewed studies on NTM-PD treatment failure published from inception until 31 January 2024, examining associated factors, intensification strategies, and supportive measures. Twenty-five studies met the inclusion criteria, mostly retrospective and observational, focusing on pulmonary disease by Mycobacterium avium complex and Mycobacterium abscessus species. Findings were synthesised qualitatively because of substancial heterogeneity in study design and outcomes.Results Before treatment intensification or de-escalation, the impact of antibiotics on health-related quality of life and microbiological factors, including acquired resistance and pathogen shifts, should be assessed. Severe baseline radiological findings and multiple prior regimen modifications were associated with lower treatment success. Evidence for supportive interventions—such as nutritional counselling, respiratory rehabilitation, and psychosocial support—remains limited. Intermittent intravenous antibiotics may aid symptom control. Depending on NTM species, additional antibiotics have been explored to intensify treatment, though evidence is largely observational. Surgical resection may be considered for localised disease, but recurrence risk remains substantial, particularly with preoperative positive cultures. Novel therapeutic approaches remain under investigation as potential alternatives.Discussion This systematic review underscores the complexity of managing refractory NTM-PD, highlighting the role of treatment intensification, symptom control, supportive measures, and knowledge gaps. While no standardised approach exists, individualised strategies incorporating clinical, microbiological, and radiological factors remain essential for optimising patient outcomes.

Importance:Experiences of marginalization by gender minority people may predispose them to poorer mental health outcomes than their cisgender peers. Understanding mental health conditions in transgender (trans) and nonbinary people is an essential step in addressing potential inequities in outcome for gender minority people. Objective:To synthesize reviews of mental health and neurodevelopmental conditions in trans and nonbinary people to describe epidemiology, key themes, and research gaps. Evidence Review:Three bibliographic databases (Embase, MEDLINE, and PsycINFO) were systematically searched from inception to August 21, 2023, to identify reviews addressing mental health and neurodevelopmental outcomes in trans and nonbinary people. Articles were screened by 2 reviewers and prespecified data were extracted. Quality of included reviews was appraised against AMSTAR2 criteria. Findings:Of 7496 unique records, 41 met inclusion criteria with 24 reviews synthesized after excluding those containing overlapping primary studies. Pooled prevalence estimates from meta-analyses were identified for 5 outcomes: suicidal ideation (50%; 95% CI, 42-57), suicide attempts (29%; 95% CI, 25-34), nonsuicidal self-injury (47%; 95% CI, 40-54), eating disorders (18%; 95% CI, 16-19), and autistic spectrum conditions (11%; 95% CI, 8-16). Meta-analyses comparing trans and cisgender groups reported higher odds of suicidal ideation (odds ratio [OR], 3.48; 95% CI, 2.41-4.91), suicide attempts (OR, 3.45; 95% CI, 2.40-4.64), nonsuicidal self-injury (OR, 3.42; 95% CI, 1.99-5.89), and posttraumatic stress disorder (OR, 2.52; 95% CI, 2.22-2.87). Worse outcomes were reported across all narrative syntheses comparing trans and cisgender or general population groups, except for problem gambling, where the limited evidence base was conflicting. No reviews assessed incidence or mortality, and there was limited disaggregation of nonbinary people or by specific gender subgroups (eg, trans men and trans women). Review quality was generally poor. Reviews highlighted heterogeneity in definitions of gender identity and outcome ascertainment, and unrepresentative sample populations as limitations of primary studies. Conclusions and Relevance:A growing body of evidence suggests trans people experience worse mental health outcomes than cisgender people, but there are substantial gaps and methodological weaknesses in existing literature. Research applying an intersectional lens, using longitudinal data and reflecting diversity and the experience of multiple disadvantages in the gender minority population is required to ensure evidence-informed policy and health service development.

Rationale Nontuberculous mycobacterial (NTM) infections are increasing worldwide and among the different species of NTM causing pulmonary infections, Mycobacterium avium complex (MAC) are most commonly isolated worldwide. Guideline based first line treatment includes a macrolide, ethambutol and rifamycin. An important aspect to combination therapy is the avoidance macrolide resistance, for which ethambutol is key companion drug. Optic toxicity is an important adverse effect of ethambutol and occurs in 0.7-6% patients in reported studies. It has been shown to be less common when ethambutol is administered thrice weekly as opposed to daily. There is a lack of consensus and literature around whether a rechallenge should be attempted, however given the imperative of keeping ethambutol in the regimen, it has been proposed. This study aims to establish the characteristics of ethambutol-induced optic toxicity amongst patients treated with ethambutol for MAC-PD, and to document the outcomes of ethambutol rechallenge in such patients. Methods Prescribing data from 2000-2024 was obtained from pharmacies at two major treating hospitals in Brisbane, Australia dispensing for 3 major NTM clinics (Greenslopes Private, Princess Alexandra and The Prince Charles Hospitals). Clinical details of treatment were obtained from chart records. Results Of 209 patients, 168 were treated with a daily regimen of ethambutol (15mg/kg/day) and 41 were treated with a thrice weekly regimen (25mg/kg/day). Seventeen patients (8.13%) developed optic toxicity, most commonly deterioration in visual acuity (n=8), visual fields (n=5) and colour vision (n=4), all of which resolved after cessation of ethambutol. The mean cumulative dose of ethambutol prior to the development of toxicity was 225.3g (±144.2g; 28.0-550.4g) over a mean of 8.6 months (± 5.6; 1.2-22.7). Seven out of eight patients (87.5%) were successfully rechallenged with a thrice weekly regimen, six of them at 25mg/kg/day with no recurrence of previous ethambutol-induced optic toxicity and the remaining one was successful with 15mg/kg/day. One patient failed rechallenge had recurrent optic toxicity characterised by asymmetrical bitemporal visual field loss, which again resolved after cessation of ethambutol. Conclusion This study has shown that rechallenge with a thrice weekly dosage of 15-25mg/kg/day of ethambutol was safe and mostly effective, hence may be attempted with close ophthalmic follow-up as early signs of recurrent ocular toxicity are largely reversible on ethambutol cessation.

INTRODUCTION:Mycobacteroides abscessus (MABS) is within the non-tuberculous mycobacteria family. It inhabits soil and water, exhibits multi-antibiotic resistance and causes opportunistic lung infections, which may progress to symptomatic MABS-pulmonary disease (MABS-PD) associated with substantial morbidity, increased healthcare utilisation, impaired quality of life and increased mortality. Treatment regimens for MABS-PD are highly variable, not evidence-based and involve complex, expensive drug combinations administered for prolonged periods (>12 months) with frequent adverse effects and treatment failure. There is an urgent need for safe, efficacious and cost-effective MABS-PD therapy. Here, we describe the Master Protocol for the Finding the Optimal Regimen for Mycobacteroides abscessus Treatment (FORMaT) trial. FORMaT aims to determine the most effective and best tolerated treatment for MABS-PD as defined by MABS clearance from respiratory samples with good treatment tolerance. METHODS AND ANALYSIS:FORMaT is an international multicentre, adaptive platform trial evaluating treatment combinations for MABS-PD. Participants are randomised multiple times during the trial, with assessment of the primary outcome of clearance of MABS infection with good treatment tolerance. Initially, therapies recommended in international consensus guidelines are being tested. Data obtained will eliminate therapies lacking efficacy or causing unacceptable toxicity. Novel treatments can then be added and tested against previously determined optimal approaches, leading in an iterative fashion to improved microbiological clearance and health outcomes. In parallel, an Observational cohort and several integrated and discovery studies are embedded in FORMaT to identify biomarkers of MABS-PD and MABS clearance, clinical and radiographic treatment response, drug pharmacokinetics and Mycobacteroides genomics and resistome. ETHICS AND DISSEMINATION:The FORMaT Master Protocol and related documents are approved by regulatory authorities in each participating jurisdiction and/or site. Results will be published in peer-reviewed journals and presented at scientific meetings. De-identified, aggregated data will be shared on an approved online platform. TRIAL REGISTRATION NUMBERS:NCT04310930, ANZCTR12618001831279, 2020-000050-10, ISRCTN67303903.

Rationale. Guideline based therapy (GBT) for Mycobacterium avium complex (MAC) infections consists of a three-drug regimen (macrolide + ethambutol + rifamycin).1 Patients who fail to culture convert their sputum to negative after six-months of (GBT) are deemed refractory. Guidelines recommend the addition of amikacin liposomal inhalation suspension (ALIS). ALIS was FDA approved in 2018 for this indication but is currently only available in Australia under a compassionate use programme. Methods. Identification of refractory patients treated with ALIS was undertaken at three speciality mycobacterial clinics in Brisbane, Australia. Baseline demographics, duration of GBT and ALIS therapy were recorded. Patients were asked to submit monthly sputum cultures. Successful therapy was defined as the achievement of 12-months of negative sputum cultures whilst on therapy. Results. From 2015 – 2024, 43 patients receiving ALIS were identified. Mean age at commencement of ALIS was 63 years (SD ±10); 77% were female. The most common NTM infection was M. i ntracellulare (58%), followed by M. a vium (21%) and M. a bscessus (9%). Radiology revealed nodular bronchiectasis (NB) in 38, NB with cavities and fibrocavitary changes in three patients each. The most common background regimens were macrolide and ethambutol based with; clofazimine (37%) or a rifamycin (30%). Twelve patients (28%) were on a four-drug oral regimen at the time of commencing ALIS. Two patients (5%) were on an alternate three-drug combination due to tolerability issues. Mean duration of GBT prior to ALIS was 2.8 years (SD± 2.3 yr). No serious TEAE were reported. The most prevalent TEAE were dysphonia (56%) and cough (47%). Temporary interruption was required in 20 patients (47%) however an intermittent dosing regimen (e.g., second daily administration) led to better tolerability and sustained compliance in all but three (7%) patients, who ceased therapy. Haemoptysis was infrequently reported and self-limiting (14%). Bilateral upper lobe ground glass infiltrates on CT imaging were noted in five (12%) patients during treatment with ALIS. ALIS was continued and radiological changes resolved on post-treatment imaging. Sputum culture conversion was achieved in 21 patients (62%) within six months of commencement of ALIS, increasing to 26 patients (76%) at 12 months with continued treatment. Culture conversion in M. abscessus patients at six months was 80% (n = 4). Conclusions. Our real-world experience of ALIS shows that it is a well-tolerated and efficacious add-on therapy in patients with NTM-PD. TEAE reported in our study were non-serious and did not result in substantial treatment discontinuation.

Antibiotic development and treatment focus on bacterial growth inhibition, often with limited success. Here, we introduce Antimicrobial Single-Cell Testing (ASCT), an advanced imaging strategy to assess bacterial killing in real-time. By tracking 140 million bacteria and generating over 20,000 in vitro time-kill curves, we can predict Mycobacterium tuberculosis treatment outcomes in mice and humans and link strain-specific survival (drug tolerance) in Mycobacterium abscessus to clinical responses. Using ASCT, we reveal drug tolerance as a distinct genetically encoded bacterial trait conserved across drugs with similar targets and, via genome-wide associations, uncover molecular mechanisms that govern bacterial killing. This study establishes the technical framework and in vivo validation for large-scale bacterial killing assessments to advance our understanding of bacterial survival and enhance antibiotic development and clinical decision-making. ### Competing Interest Statement The authors have declared no competing interest.

Background Although airway clearance techniques (ACTs) and physical exercise are recommended for adults with bronchiectasis, there is little data on current practice and limited guidance predicting clinical approach. Objective This study aimed to describe current ACT and exercise practice recorded by patients, and identify predictors of regular ACTs, ACT modalities and exercise. Methods Physiotherapy-specific interventions, quality of life (Quality-of-Life Bronchiectasis questionnaire, QOL-B), demographics and disease severity were extracted from the Australian Bronchiectasis Registry. Multivariate analyses were undertaken to identify predictors of undertaking ACTs or exercise. Results We included 461 patients; median age of 72 years (interquartile range 64-78 years). Regular ACT use was recorded by 266 (58%) patients; the active cycle of breathing technique (n=175, 74%) was the most common technique. Regular exercise use was recorded by 213 (46%) patients, with walking the most common form of exercise. A pulmonary rehabilitation referral was made for 90 (19.5%) of patients. Regular ACT use was associated with a higher treatment burden on QOL-B (Odds ratio (OR)=0.97, 95% confidence interval (CI) 0.96 to 0.99). Regular exercise was more likely amongst patients with severe bronchiectasis compared to those with mild disease (OR=9.46, 95% CI 1.94 to 67.83) and in those with greater physical function on the QOL-B (OR=1.02, 95% CI 1.01 to 1.04). Conclusion Approximately half the adults in the registry report regular ACT or exercise; QOL and disease severity predict this engagement. This knowledge may guide the tailoring of ACTs and exercise prescription to optimise physiotherapy management in adults with bronchiectasis.

BACKGROUND:Population mental health in the United Kingdom (UK) has deteriorated, alongside worsening socioeconomic conditions, over the last decade. Policies such as Universal Basic Income (UBI) have been suggested as an alternative economic approach to improve population mental health and reduce health inequalities. UBI may improve mental health (MH), but to our knowledge, no studies have trialled or modelled UBI in whole populations. We aimed to estimate the short-term effects of introducing UBI on mental health in the UK working-age population. METHODS AND FINDINGS:Adults aged 25 to 64 years were simulated across a 4-year period from 2022 to 2026 with the SimPaths microsimulation model, which models the effects of UK tax/benefit policies on mental health via income, poverty, and employment transitions. Data from the nationally representative UK Household Longitudinal Study were used to generate the simulated population (n = 25,000) and causal effect estimates. Three counterfactual UBI scenarios were modelled from 2023: "Partial" (value equivalent to existing benefits), "Full" (equivalent to the UK Minimum Income Standard), and "Full+" (retaining means-tested benefits for disability, housing, and childcare). Likely common mental disorder (CMD) was measured using the General Health Questionnaire (GHQ-12, score ≥4). Relative and slope indices of inequality were calculated, and outcomes stratified by gender, age, education, and household structure. Simulations were run 1,000 times to generate 95% uncertainty intervals (UIs). Sensitivity analyses relaxed SimPaths assumptions about reduced employment resulting from Full/Full+ UBI. Partial UBI had little impact on poverty, employment, or mental health. Full UBI scenarios practically eradicated poverty but decreased employment (for Full+ from 78.9% [95% UI 77.9, 79.9] to 74.1% [95% UI 72.6, 75.4]). Full+ UBI increased absolute CMD prevalence by 0.38% (percentage points; 95% UI 0.13, 0.69) in 2023, equivalent to 157,951 additional CMD cases (95% UI 54,036, 286,805); effects were largest for men (0.63% [95% UI 0.31, 1.01]) and those with children (0.64% [95% UI 0.18, 1.14]). In our sensitivity analysis assuming minimal UBI-related employment impacts, CMD prevalence instead fell by 0.27% (95% UI -0.49, -0.05), a reduction of 112,228 cases (95% UI 20,783, 203,673); effects were largest for women (-0.32% [95% UI -0.65, 0.00]), those without children (-0.40% [95% UI -0.68, -0.15]), and those with least education (-0.42% [95% UI -0.97, 0.15]). There was no effect on educational mental health inequalities in any scenario, and effects waned by 2026. The main limitations of our methods are the model's short time horizon and focus on pathways from UBI to mental health solely via income, poverty, and employment, as well as the inability to integrate macroeconomic consequences of UBI; future iterations of the model will address these limitations. CONCLUSIONS:UBI has potential to improve short-term population mental health by reducing poverty, particularly for women, but impacts are highly dependent on whether individuals choose to remain in employment following its introduction. Future research modelling additional causal pathways between UBI and mental health would be beneficial.