Erdosteine in children and adults with bronchiectasis (BETTER trial): study protocol for a multicentre, double-blind, randomised controlled trial.

INTRODUCTION: Bronchiectasis is a worldwide chronic lung disorder where exacerbations are common. It affects people of all ages, but especially Indigenous populations in high-income nations. Despite being a major contributor to chronic lung disease, there are no licensed therapies for bronchiectasis and there remain relatively few randomised controlled trials (RCTs) conducted in children and adults. Our RCT will address some of these unmet needs by evaluating whether the novel mucoactive agent, erdosteine, has a therapeutic role in children and adults with bronchiectasis.Our primary aim is to determine in children and adults aged 2-49 years with bronchiectasis whether regular erdosteine over a 12-month period reduces acute respiratory exacerbations compared with placebo. Our primary hypothesis is that people with bronchiectasis who regularly use erdosteine will have fewer exacerbations than those receiving placebo.Our secondary aims are to determine the effect of the trial medications on quality of life (QoL) and other clinical outcomes (exacerbation duration, time-to-next exacerbation, hospitalisations, lung function, adverse events). We will also assess the cost-effectiveness of the intervention. METHODS AND ANALYSIS: We are undertaking an international multicentre, double-blind, placebo-RCT to evaluate whether 12 months of erdosteine is beneficial for children and adults with bronchiectasis. We will recruit 194 children and adults with bronchiectasis to a parallel, superiority RCT at eight sites across Australia, Malaysia and Philippines. Our primary endpoint is the rate of exacerbations over 12 months. Our main secondary outcomes are QoL, exacerbation duration, time-to-next exacerbation, hospitalisations and lung function. ETHICS AND DISSEMINATION: The Human Research Ethics Committees (HREC) of Children's Health Queensland (for all Australian sites), University of Malaya Medical Centre (Malaysia) and St. Luke's Medical Centre (Philippines) approved the study. We will publish the results and share the outcomes with the academic and medical community, funding and relevant patient organisations. TRIAL REGISTRATION NUMBER: ACTRN12621000315819.

Liver and pancreatic-targeted interleukin-22 as a therapeutic for metabolic dysfunction-associated steatohepatitis.

Metabolic dysfunction-associated steatohepatitis (MASH) is the most prevalent cause of liver disease worldwide, with a single approved therapeutic. Previous research has shown that interleukin-22 (IL-22) can suppress ß-cell stress, reduce local islet inflammation, restore appropriate insulin production, reverse hyperglycemia, and ameliorate insulin resistance in preclinical models of diabetes. In clinical trials long-acting forms of IL-22 have led to increased proliferation in the skin and intestine, where the IL-22RA1 receptor is highly expressed. To maximise beneficial effects whilst reducing the risk of epithelial proliferation and cancer, we designed short-acting IL-22-bispecific biologic drugs that successfully targeted the liver and pancreas. Here we show 10-fold lower doses of these bispecific biologics exceed the beneficial effects of native IL-22 in multiple preclinical models of MASH, without off-target effects. Treatment restores glycemic control, markedly reduces hepatic steatosis, inflammation, and fibrogenesis. These short-acting IL-22-bispecific targeted biologics are a promising new therapeutic approach for MASH.

Pancreatic beta-cell IL-22 receptor deficiency induces age-dependent dysregulation of insulin biosynthesis and systemic glucose homeostasis.

The IL-22RA1 receptor is highly expressed in the pancreas, and exogenous IL-22 has been shown to reduce endoplasmic reticulum and oxidative stress in human pancreatic islets and promote secretion of high-quality insulin from beta-cells. However, the endogenous role of IL-22RA1 signaling on these cells remains unclear. Here, we show that antibody neutralisation of IL-22RA1 in cultured human islets leads to impaired insulin quality and increased cellular stress. Through the generation of mice lacking IL-22ra1 specifically on pancreatic alpha- or beta-cells, we demonstrate that ablation of murine beta-cell IL-22ra1 leads to similar decreases in insulin secretion, quality and islet regeneration, whilst increasing islet cellular stress, inflammation and MHC II expression. These changes in insulin secretion led to impaired glucose tolerance, a finding more pronounced in female animals compared to males. Our findings attribute a regulatory role for endogenous pancreatic beta-cell IL-22ra1 in insulin secretion, islet regeneration, inflammation/cellular stress and appropriate systemic metabolic regulation.

Efficacy of biologically-directed daylight therapy on sleep and circadian rhythm in Parkinson's disease: a randomised, double-blind, parallel-group, active-controlled, phase 2 clinical trial.

Background: New non-pharmacological treatments for improving non-motor symptoms in Parkinson's disease (PD) are urgently needed. Previous light therapies for modifying sleep behaviour lacked standardised protocols and were not personalised for an individual patient chronotype. We aimed to assess the efficacy of a biologically-directed light therapy in PD that targets retinal inputs to the circadian system on sleep, as well as other non-motor and motor functions. Methods: In this randomised, double-blind, parallel-group, active-controlled trial at the Queensland University of Technology, Australia, participants with mild to moderate PD were computer randomised (1:1) to receive one of two light therapies that had the same photometric luminance and visual appearance to allow blinding of investigators and participants to the intervention. One of these biologically-directed lights matched natural daylight (Day Mel), which is known to stimulate melanopsin cells. The light therapy of the other treatment arm of the study, specifically supplemented the stimulation of retinal melanopsin cells (Enhanced Mel), targeting deficits to the circadian system. Both lights were administered 30 min per day over 4-weeks and personalised to an individual patient's chronotype, while monitoring environmental light exposure with actigraphy. Co-primary endpoints were a change from baseline in mean sleep macrostructure (polysomnography, PSG) and an endocrine biomarker of circadian phase (dim light melatonin secretion onset, DLMO) at weeks 4 and 6. Participants data were analysed using an intention to treat principle. All endpoints were evaluated by applying a mixed model analysis. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12621000077864. Findings: Between February 4, 2021 and August 8, 2022, 144 participants with PD were consecutively screened, 60 enrolled and randomly assigned to a light intervention. There was no significant difference in co-primary outcomes between randomised groups overall or at any individual timepoint during follow-up. The mean (95% CI) for PSG, N3% was 24.15 (19.82-28.48) for Day Mel (n = 23) and 19.34 (15.20-23.47) for the Enhanced Mel group (n = 25) in week 4 (p = 0.12); and 21.13 (16.99-25.28) for Day Mel (n = 26) and 18.48 (14.34-22.62) for the Enhanced Mel group (n = 25) in week 6, (p = 0.37). The mean (95% CI) DLMO (decimal time) was 19.82 (19.20-20.44) for Day Mel (n = 22) and 19.44 (18.85-20.04) for the Enhanced Mel group (n = 24) in week 4 (p = 0.38); and 19.90 (19.27-20.53) for Day Mel (n = 23) and 19.04 (18.44-19.64) for the Enhanced Mel group (n = 25) in week 6 (p = 0.05). However, both the controlled daylight (Day Mel) and the enhanced melanopsin (Enhanced Mel) interventions demonstrated significant improvement in primary PSG sleep macrostructure. The restorative deep sleep phase (PSG, N3) significantly improved at week 6 in both groups [model-based mean difference to baseline (95% CI): -3.87 (-6.91 to -0.83), p = 0.04]. There was a phase-advance in DLMO in both groups which did not reach statistical significance between groups at any time-point. There were no safety concerns or severe adverse events related to the intervention. Interpretation: Both the controlled daylight and melanopsin booster light showed efficacy in improving measures of restorative deep sleep in people with mild to moderate PD. That there was no significant difference between the two intervention groups may be due to the early disease stage. The findings suggest that controlled indoor daylight that is personalised to the individuals' chronotype could be effective for improving sleep in early to moderate PD, and further studies evaluating controlled daylight interventions are now required utilising this standardised approach, including in advanced PD. Funding: The Michael J Fox Foundation for Parkinson's Research, Shake IT Up Australia, National Health and Medical Research Council, and Australian Research Council.

The role of N-glycosylation in spike antigenicity for the SARS-CoV-2 gamma variant.

The emergence of SARS-CoV-2 variants alters the efficacy of existing immunity towards the viral spike protein, whether acquired from infection or vaccination. Mutations that impact N-glycosylation of spike may be particularly important in influencing antigenicity, but their consequences are difficult to predict. Here, we compare the glycosylation profiles and antigenicity of recombinant viral spike of ancestral Wu-1 and the Gamma strain, which has two additional N-glycosylation sites due to amino acid substitutions in the N-terminal domain (NTD). We found that a mutation at residue 20 from threonine to asparagine within the NTD caused the loss of NTD-specific antibody COVA2-17 binding. Glycan site-occupancy analyses revealed that the mutation resulted in N-glycosylation switching to the new sequon at N20 from the native N17 site. Site-specific glycosylation profiles demonstrated distinct glycoform differences between Wu-1, Gamma, and selected NTD variant spike proteins, but these did not affect antibody binding. Finally, we evaluated the specificity of spike proteins against convalescent COVID-19 sera and found reduced cross-reactivity against some mutants, but not Gamma spike compared to Wuhan spike. Our results illustrate the impact of viral divergence on spike glycosylation and SARS-CoV-2 antibody binding profiles.

Pregnancy in women with cystic fibrosis and diabetes: An audit of outcomes at two tertiary obstetric hospitals in Australia in the pre-cystic fibrosis transmembrane conductance regulator modulator era.

Background: Pregnancy in women with cystic fibrosis (CF) is becoming more common. Long-term metabolic issues such as diabetes are also becoming more common and have potentially important impacts on pregnancy outcomes. This study aimed to assess the impact of diabetes on pregnancy outcomes for women with CF. Methods: We undertook a retrospective chart audit of pregnancies to women with CF at the two tertiary obstetric hospitals in Southeast Queensland associated with CF and transplant management clinics between 2006 and 2016. Results: A total of 38 pregnancies among 26 women were identified. Four women (five pregnancies) had cystic fibrosis-related diabetes (CFRD) diagnosed prior to pregnancy, and 12 women (15 pregnancies) developed gestational diabetes (GDM) complicating pregnancy. CFRD and GDM were associated with higher rates of delivery complications, prematurity, and the need for neonatal intensive care unit admission. Conclusion: Diabetes is common during pregnancy in women with CF and impacts pregnancy outcomes.

Genomic analyses of Burkholderia respiratory isolates indicates two evolutionarily distinct B. anthina clades.

Introduction: The Burkholderia cepacia complex (BCC) encompasses a group of at least 22 genetically distinct gram-negatives bacterial species ubiquitous in nature. Recognised as a group of genetically and phenotypically flexible species, the BCC inhabits diverse ecological niches causing both plant and human diseases. Comparative genomic analysis provides an in depth understanding into the population biology, phylogenetic relationship, and genomic architecture of species. Methods: Here, we genomically characterise Burkholderia anthina isolated from patients with chronic lung infections, an understudied pathogen within the Burkholderia cepacia complex. Results: We demonstrate that B. anthina is polyphyletic and constitutes two distinct evolutionary lineages. Core- and pan-genome analyses demonstrated substantial metabolic diversity, with B. anthina Clade I enriched in genes associated with microbial metabolism in diverse environments, including degradation of aromatic compounds and metabolism of xenobiotics, while B. anthina Clade II demonstrated an enhanced capability for siderophore biosynthesis. Discussion: Based on our phylogenetic and comparative genomic analyses, we suggest stratifying B. anthina to recognise a distinct species harbouring increased potential for iron metabolism via siderophore synthesis, for which we propose the name Burkholderia anthinoferum (sp. nov.).

Elevated BMI reduces the humoral response to SARS-CoV-2 infection.

Objective: Class III obesity (body mass index [BMI] ≥ 40 kg m-2) significantly impairs the immune response to SARS-CoV-2 vaccination. However, the effect of an elevated BMI (≥ 25 kg m-2) on humoral immunity to SARS-CoV-2 infection and COVID-19 vaccination remains unclear. Methods: We collected blood samples from people who recovered from SARS-CoV-2 infection approximately 3 and 13 months of post-infection (noting that these individuals were not exposed to SARS-CoV-2 or vaccinated in the interim). We also collected blood samples from people approximately 5 months of post-second dose COVID-19 vaccination (the majority of whom did not have a prior SARS-CoV-2 infection). We measured their humoral responses to SARS-CoV-2, grouping individuals based on a BMI greater or less than 25 kg m-2. Results: Here, we show that an increased BMI (≥ 25 kg m-2), when accounting for age and sex differences, is associated with reduced antibody responses after SARS-CoV-2 infection. At 3 months of post-infection, an elevated BMI was associated with reduced antibody titres. At 13 months of post-infection, an elevated BMI was associated with reduced antibody avidity and a reduced percentage of spike-positive B cells. In contrast, no significant association was noted between a BMI ≥ 25 kg m-2 and humoral immunity to SARS-CoV-2 at 5 months of post-secondary vaccination. Conclusions: Taken together, these data showed that elevated BMI is associated with an impaired humoral immune response to SARS-CoV-2 infection. The impairment of infection-induced immunity in individuals with a BMI ≥ 25 kg m-2 suggests an added impetus for vaccination rather than relying on infection-induced immunity.

Interleukin-22 suppresses major histocompatibility complex II in mucosal epithelial cells.

Major histocompatibility complex (MHC) II is dynamically expressed on mucosal epithelial cells and is induced in response to inflammation and parasitic infections, upon exposure to microbiota, and is increased in chronic inflammatory diseases. However, the regulation of epithelial cell-specific MHC II during homeostasis is yet to be explored. We discovered a novel role for IL-22 in suppressing epithelial cell MHC II partially via the regulation of endoplasmic reticulum (ER) stress, using animals lacking the interleukin-22-receptor (IL-22RA1), primary human and murine intestinal and respiratory organoids, and murine models of respiratory virus infection or with intestinal epithelial cell defects. IL-22 directly downregulated interferon-γ-induced MHC II on primary epithelial cells by modulating the expression of MHC II antigen A α (H2-Aα) and Class II transactivator (Ciita), a master regulator of MHC II gene expression. IL-22RA1-knockouts have significantly higher MHC II expression on mucosal epithelial cells. Thus, while IL-22-based therapeutics improve pathology in chronic disease, their use may increase susceptibility to viral infections.

The Impact of Long-Term Macrolide Exposure on the Gut Microbiome and Its Implications for Metabolic Control.

Long-term low-dose macrolide therapy is now widely used in the treatment of chronic respiratory diseases for its immune-modulating effects, although the antimicrobial properties of macrolides can also have collateral impacts on the gut microbiome. We investigated whether such treatment altered intestinal commensal microbiology and whether any such changes affected systemic immune and metabolic regulation. In healthy adults exposed to 4 weeks of low-dose erythromycin or azithromycin, as used clinically, we observed consistent shifts in gut microbiome composition, with a reduction in microbial capacity related to carbohydrate metabolism and short-chain fatty acid biosynthesis. These changes were accompanied by alterations in systemic biomarkers relating to immune (interleukin 5 [IL-5], IL-10, monocyte chemoattractant protein 1 [MCP-1]) and metabolic (serotonin [5-HT], C-peptide) homeostasis. Transplantation of erythromycin-exposed murine microbiota into germ-free mice demonstrated that changes in metabolic homeostasis and gastrointestinal motility, but not systemic immune regulation, resulted from changes in intestinal microbiology caused by macrolide treatment. Our findings highlight the potential for long-term low-dose macrolide therapy to influence host physiology via alteration of the gut microbiome. IMPORTANCE Long-term macrolide therapy is widely used in chronic respiratory diseases although its antibacterial activity can also affect the gut microbiota, a key regulator of host physiology. Macrolide-associated studies on the gut microbiota have been limited to short antibiotic courses and have not examined its consequences for host immune and metabolic regulation. This study revealed that long-term macrolides depleted keystone bacteria and impacted host regulation, mediated directly by macrolide activity or indirectly by alterations to the gut microbiota. Understanding these macrolide-associated mechanisms will contribute to identifying the risk of long-term exposure and highlights the importance of targeted therapy for maintenance of the gut microbiota.

Subjective and objective sleep quality does not predict behavioural episodic foresight in younger or older adults.

Episodic foresight refers to one's capacity to use imagined scenarios to guide future-directed behaviors. It is important in facilitating complex activities of daily living, such as managing finances. Broader literature shows that older adults perform more poorly on tests of episodic foresight relative to their younger counterparts. At the same time, age-related changes in sleep often contribute to age-related decline in other cognitive abilities known to support episodic foresight, such as memory. No study to date has tested whether sleep quality is associated with episodic foresight when it is measured behaviorally; or whether this relationship is moderated by age. To address this, in the present study healthy younger (n = 39) and older (n = 41) adults were asked to wear an actigraphy watch and self-report their sleep quality for seven nights. Participants then completed the virtual-week foresight task-a behavioral assessment of episodic foresight. Neither objective or subjective sleep quality predicted episodic foresight outcomes, and this was not moderated by age group. Bayesian analyses provided evidence in favour of the null hypotheses. These results suggest that sleep quality (at least in healthy adult populations) may not be linked to episodic foresight.

GPR183 antagonism reduces macrophage infiltration in influenza and SARS-CoV-2 infection.

RATIONALE: Severe viral respiratory infections are often characterised by extensive myeloid cell infiltration and activation and persistent lung tissue injury. However, the immunological mechanisms driving excessive inflammation in the lung remain poorly understood. OBJECTIVES: To identify the mechanisms that drive immune cell recruitment in the lung during viral respiratory infections and identify novel drug targets to reduce inflammation and disease severity. METHODS: Preclinical murine models of influenza A virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. RESULTS: Oxidised cholesterols and the oxysterol-sensing receptor GPR183 were identified as drivers of monocyte/macrophage infiltration to the lung during influenza A virus (IAV) and SARS-CoV-2 infection. Both IAV and SARS-CoV-2 infection upregulated the enzymes cholesterol 25-hydroxylase (CH25H) and cytochrome P450 family 7 subfamily member B1 (CYP7B1) in the lung, resulting in local production of the oxidised cholesterols 25-hydroxycholesterol (25-OHC) and 7α,25-dihydroxycholesterol (7α,25-OHC). Loss-of-function mutation of Gpr183 or treatment with a GPR183 antagonist reduced macrophage infiltration and inflammatory cytokine production in the lungs of IAV- or SARS-CoV-2-infected mice. The GPR183 antagonist significantly attenuated the severity of SARS-CoV-2 infection and viral loads. Analysis of single-cell RNA-sequencing data on bronchoalveolar lavage samples from healthy controls and COVID-19 patients with moderate and severe disease revealed that CH25H, CYP7B1 and GPR183 are significantly upregulated in macrophages during COVID-19. CONCLUSION: This study demonstrates that oxysterols drive inflammation in the lung via GPR183 and provides the first preclinical evidence for the therapeutic benefit of targeting GPR183 during severe viral respiratory infections.

'Teach me how to look after myself': What people with bronchiectasis want from education in a pulmonary rehabilitation setting.

INTRODUCTION: Pulmonary rehabilitation is recommended for people with bronchiectasis. Various education topics are included in these programmes, but the content is largely guided by the needs of people with other respiratory conditions. OBJECTIVES: With the education topics applicable to people with bronchiectasis unclear, we aimed to explore the perspective of adults with this condition on relevant educational topics in a pulmonary rehabilitation context. METHODS: Participants from the Australian Bronchiectasis Registry were invited to undertake a semi-structured interview. Interview transcripts were coded independently, with themes established by consensus (two researchers). RESULTS: Twenty-one people participated. The major themes were greater clarity on the underlying cause of bronchiectasis and prognosis. Most sought knowledge about self-management strategies and treatments to address extra-pulmonary symptoms. Participants requested more information on physiotherapy options and the role of exercise and physical activity outside of pulmonary rehabilitation. Preferences were mixed for the education delivery model. CONCLUSIONS: We have identified unmet educational topics of interest for people with bronchiectasis. Our study provides a framework for education topics desired by adults with bronchiectasis within a pulmonary rehabilitation setting. The topics identified will guide development of an education curriculum for pulmonary rehabilitation that is more fit-for-purpose for people with bronchiectasis.

Emotion regulation mediates the effects of sleep on stress and aggression.

It is well established that poor sleep directly increases stress and aggression, but potential mediators of this relationship remain poorly understood. The present study provided the first direct test of whether capacity for emotion regulation mediated the relationship between sleep with stress. It also aimed to extend current understanding of whether emotion regulation might mediate the association between sleep and aggression, by assessing four distinct subcomponents of aggression (anger, hostility, verbal aggression, and physical aggression). In service of these goals, 740 participants completed validated measures of sleep, stress, aggression, and emotion regulation. Results showed that emotion regulation partially mediated the relationship between sleep quality with stress, anger, hostility, and verbal aggression, and fully mediated the relationship between sleep with physical aggression. These data provide novel evidence that emotion regulation abilities may serve as a protective factor against the negative consequences of sleep disturbances.

Care for adults with COVID-19: living guidelines from the National COVID-19 Clinical Evidence Taskforce.

INTRODUCTION: The Australian National COVID-19 Clinical Evidence Taskforce was established in March 2020 to maintain up-to-date recommendations for the treatment of people with coronavirus disease 2019 (COVID-19). The original guideline (April 2020) has been continuously updated and expanded from nine to 176 recommendations, facilitated by the rapid identification, appraisal, and analysis of clinical trial findings and subsequent review by expert panels. MAIN RECOMMENDATIONS: In this article, we describe the recommendations for treating non-pregnant adults with COVID-19, as current on 1 August 2022 (version 61.0). The Taskforce has made specific recommendations for adults with severe/critical or mild disease, including definitions of disease severity, recommendations for therapy, COVID-19 prophylaxis, respiratory support, and supportive care. CHANGES IN MANAGEMENT AS A RESULT OF THE GUIDELINE: The Taskforce currently recommends eight drug treatments for people with COVID-19 who do not require supplemental oxygen (inhaled corticosteroids, casirivimab/imdevimab, molnupiravir, nirmatrelvir/ritonavir, regdanvimab, remdesivir, sotrovimab, tixagevimab/cilgavimab) and six for those who require supplemental oxygen (systemic corticosteroids, remdesivir, tocilizumab, sarilumab, baricitinib, casirivimab/imdevimab). Based on evidence of their achieving no or only limited benefit, ten drug treatments or treatment combinations are not recommended; an additional 42 drug treatments should only be used in the context of randomised trials. Additional recommendations include support for the use of continuous positive airway pressure, prone positioning, and endotracheal intubation in patients whose condition is deteriorating, and prophylactic anticoagulation for preventing venous thromboembolism. The latest updates and full recommendations are available at www.covid19evidence.net.au.

Assessment of Long-Term Macrolide Exposure on the Oropharyngeal Microbiome and Macrolide Resistance in Healthy Adults and Consequences for Onward Transmission of Resistance.

While the use of long-term macrolide therapy to prevent exacerbations in chronic respiratory diseases is widespread, its impact on the oropharyngeal microbiota and macrolide resistance, and the potential for onward transmission of resistance to close contacts are poorly understood. We determined the effects of long-term exposure to azithromycin or erythromycin on phenotypic and genotypic macrolide resistance within the oropharyngeal microbiome of healthy adults and their close contacts in a randomized, single-blinded, parallel-group trial of 4 weeks of twice-daily oral 400 mg erythromycin ethylsuccinate or twice-daily oral 125 mg azithromycin. Using oropharyngeal swabs collected from 20 index healthy adults and 20 paired close contacts, the oropharyngeal microbial composition and macrolide resistance in streptococci were assessed by 16S rRNA sequencing and antibiotic susceptibility testing of oropharyngeal cultures, respectively, at baseline and weeks 4 and 8 (washout). Targeted quantitative PCR of antibiotic resistance genes was performed to evaluate paired changes in resistance gene levels in index patients and close contacts and to relate the potential transmission of antibiotic resistance. Neither azithromycin nor erythromycin altered oropharyngeal microbiota characteristics significantly. Proportional macrolide resistance in oropharyngeal streptococci increased with both erythromycin and azithromycin, remaining above baseline levels for the azithromycin group at washout. Levels of resistance genes increased significantly with azithromycin[erm(B) and mef] and erythromycin (mef), returning to baseline levels at washout only for the erythromycin group. We found no evidence of onward transmission of resistance to close contacts, as indicated by the lack of concomitant changes in resistance gene levels detected in close contacts. (This study has been registered with the Australian and New Zealand Clinical Trials Registry under identifier ACTRN12617000278336.).

Carriage and Transmission of Macrolide Resistance Genes in Patients With Chronic Respiratory Conditions and Their Close Contacts.

BACKGROUND: Long-term macrolide therapy has been shown to provide benefit to those with a range of chronic respiratory conditions. However, concerns remain about the impact of macrolide exposure on the carriage and abundance of antibiotic resistance genes within the oropharynx. The potential for onward transmission of resistance from macrolide recipients to their close contacts also is poorly understood. RESEARCH QUESTION: Does long-term macrolide use impact carriage of resistance within the oropharyngeal microbiota in people with chronic respiratory conditions and risk of onward transmission to their close contacts? STUDY DESIGN AND METHODS: Oropharyngeal swabs were collected from 93 individuals with chronic respiratory conditions, 53 of whom were receiving long-term macrolide therapy. An oropharyngeal swab also was collected from a close cohabiting contact of each patient. Detection and abundance of 10 macrolide-associated resistance genes with the potential to disseminate via horizontal gene transfer were assessed by quantitative polymerase chain reaction analysis. RESULTS: Detection of resistance genes in macrolide recipients was comparable with that in nonrecipients. However, the normalized gene abundance of erm(B) was significantly higher in the macrolide recipient group (P = .045). Among the close contacts, no between-group differences in resistance gene detection or abundance were identified. Within-group analysis showed that the detection of erm(F) and mef in macrolide recipients, but not nonrecipients, was associated significantly with detection in close contacts (P = .003 and P = .004, respectively). However, between-group analysis showed that treatment group did not predict cocarriage between patients and their close contacts (P > .05 for each gene). INTERPRETATION: Although levels of erm(B) were higher in those receiving long-term macrolide therapy and evidence of gene cocarriage with close contacts was found, no evidence was found that macrolide use increased the onward transmission risk to their close contacts. This study therefore addresses concerns that long-term macrolide therapy could promote the dissemination of transmissible macrolide resistance.

R othia mucilaginosa is an anti-inflammatory bacterium in the respiratory tract of patients with chronic lung disease.

BACKGROUND: Chronic airway inflammation is the main driver of pathogenesis in respiratory diseases such as severe asthma, chronic obstructive pulmonary disease, cystic fibrosis (CF) and bronchiectasis. While the role of common pathogens in airway inflammation is widely recognised, the influence of other microbiota members is still poorly understood. METHODS: We hypothesised that the lung microbiota contains bacteria with immunomodulatory activity which modulate net levels of immune activation by key respiratory pathogens. Therefore, we assessed the immunomodulatory effect of several members of the lung microbiota frequently reported as present in CF lower respiratory tract samples. RESULTS: We show that Rothia mucilaginosa, a common resident of the oral cavity that is also often detectable in the lower airways in chronic disease, has an inhibitory effect on pathogen- or lipopolysaccharide-induced pro-inflammatory responses, in vitro (three-dimensional cell culture model) and in vivo (mouse model). Furthermore, in a cohort of adults with bronchiectasis, the abundance of Rothia species was negatively correlated with pro-inflammatory markers (interleukin (IL)-8 and IL-1ß) and matrix metalloproteinase (MMP)-1, MMP-8 and MMP-9 in sputum. Mechanistic studies revealed that R. mucilaginosa inhibits NF-κB pathway activation by reducing the phosphorylation of IκBα and consequently the expression of NF-κB target genes. CONCLUSIONS: These findings indicate that the presence of R. mucilaginosa in the lower airways potentially mitigates inflammation, which could in turn influence the severity and progression of chronic respiratory disorders.

Targeting the P2Y13 Receptor Suppresses IL-33 and HMGB1 Release and Ameliorates Experimental Asthma.

Rationale: The alarmins IL-33 and HMGB1 (high mobility group box 1) contribute to type 2 inflammation and asthma pathogenesis. Objectives: To determine whether P2Y13-R (P2Y13 receptor), a purinergic GPCR (G protein-coupled receptor) and risk allele for asthma, regulates the release of IL-33 and HMGB1. Methods: Bronchial biopsy specimens were obtained from healthy subjects and subjects with asthma. Primary human airway epithelial cells (AECs), primary mouse AECs, or C57Bl/6 mice were inoculated with various aeroallergens or respiratory viruses, and the nuclear-to-cytoplasmic translocation and release of alarmins was measured by using immunohistochemistry and an ELISA. The role of P2Y13-R in AEC function and in the onset, progression, and exacerbation of experimental asthma was assessed by using pharmacological antagonists and mice with P2Y13-R gene deletion. Measurements and Main Results: Aeroallergen exposure induced the extracellular release of ADP and ATP, nucleotides that activate P2Y13-R. ATP, ADP, and aeroallergen (house dust mite, cockroach, or Alternaria antigen) or virus exposure induced the nuclear-to-cytoplasmic translocation and subsequent release of IL-33 and HMGB1, and this response was ablated by genetic deletion or pharmacological antagonism of P2Y13. In mice, prophylactic or therapeutic P2Y13-R blockade attenuated asthma onset and, critically, ablated the severity of a rhinovirus-associated exacerbation in a high-fidelity experimental model of chronic asthma. Moreover, P2Y13-R antagonism derepressed antiviral immunity, increasing IFN-λ production and decreasing viral copies in the lung. Conclusions: We identify P2Y13-R as a novel gatekeeper of the nuclear alarmins IL-33 and HMGB1 and demonstrate that the targeting of this GPCR via genetic deletion or treatment with a small-molecule antagonist protects against the onset and exacerbations of experimental asthma.

The cystic fibrosis gut as a potential source of multidrug resistant pathogens.

BACKGROUND: The emergence of multidrug resistant (MDR) pathogens represents a profound threat to global health. Individuals with CF have amongst the highest cumulative antibiotic exposure of any patient group, including to critically-important last-line agents. While there is little evidence that antibiotic resistance in airway pathogens results in worse clinical outcomes for CF patients, the potential emergence of MDR pathogens in non-respiratory systems, as a consequence of CF care, represents a potential health threat to the wider population, including family and carers. METHODS: Stool from 19 adults with CF and 16 healthy adult controls was subjected to metagenomic sequencing, to assess faecal resistome, and culture-based analysis. Resistant isolates were identified phenotypically, and genetic determinants of resistance characterised by whole genome sequencing. RESULTS: CF and control faecal resistomes differed significantly (P = 0.0003). The proportion of reads that mapped to mobile genetic elements was significantly higher in CF (P = 0.014) and the composition was significantly different (P = 0.0001). Notably, CF patients displayed higher carriage of plasmid-mediated aminoglycoside-modifying genes ant(6)-Ib, aac(6')-Ip, and aph(3')-IIIa (P < 0.01). Culture-based analysis supported higher aminoglycoside resistance, with a higher proportion of aminoglycoside-resistant, Gram-negative bacteria (P < 0.0001). Isolated extended spectrum beta lactamase (ESBL)-positive Escherichia coli from CF stool exhibited phenotypic resistance to tobramycin and gentamicin. Genomic analysis showed co-localisation of both aminoglycoside resistance and ESBL genes, consistent with MDR emergence through horizontal gene transfer. CONCLUSIONS: The carriage of potentially transmissible resistance within the adult CF gut microbiome is considerably greater than in healthy individuals and could contribute to the emergence and dissemination of MDR pathogens.