RATIONALE:Cystic fibrosis (CF) is an inherited multi-organ disorder. People with CF (pwCF) experience recurrent and chronic lung infections and a progressive loss of lung function. PwCF with poor and rapidly declining lung function may be considered for lung transplantation (LTx), which may improve their quality of life and survival. Nontuberculous mycobacteria (NTM) can cause pulmonary disease in pwCF, and NTM infection is a poor prognostic factor in LTx. Guidelines recommend NTM infection should not automatically preclude LTx. It is important to evaluate the evidence base for LTx in pwCF and NTM pulmonary disease. OBJECTIVES:To evaluate clinical outcomes in pwCF and with NTM infection (NTM infection alone or with NTM pulmonary disease) who undergo LTx by comparing: 1. pwCF with current NTM lung infection who undergo LTx versus those with NTM infection who do not undergo LTX; 2. pwCF with current NTM lung infection who undergo LTx versus those without NTM undergoing LTx. SEARCH METHODS:We searched the Cochrane Cystic Fibrosis Trials Register, CENTRAL, MEDLINE, Embase, and PubMed as well as two ongoing trials registries. We checked references. The latest search date was 17 February 2026. ELIGIBILITY CRITERIA:We considered non-randomised studies of pwCF (any age) with or without NTM lung infection or disease being considered for LTx as well as studies of pwCF and NTM who either did or did not undergo LTx. OUTCOMES:Our critical outcomes were mortality, disseminated NTM infection post-LTx, time to chronic lung allograft dysfunction (CLAD), and quality of life at any time points reported. We additionally planned to report lung function, hospitalisations for pulmonary exacerbations, and nutritional parameters in the review. RISK OF BIAS:We assessed the risk of bias in three studies using ROBINS-I and in one study using the Joanna Briggs Institute checklist for case series. SYNTHESIS METHODS:We could only report results narratively. We used GRADE to assess the certainty of the evidence. INCLUDED STUDIES:We included four single-centre retrospective studies (388 adults). Sample sizes ranged from nine to 177 participants. Mycobacteria abscessus was the most common NTM species identified, and all studies reported infection with other pathogens. All studies compared pwCF and NTM infection to pwCF without NTM infection, all undergoing LTx. Each study reported mortality and disseminated NTM infection post-LTx; two studies recorded CLAD. No study reported quality of life, specific lung function measures (although one study commented briefly on lung function in general), hospitalisations for pulmonary exacerbations, or nutritional parameters. SYNTHESIS OF RESULTS:We analysed all NTM infections together for practical reasons and were not able to undertake a planned subgroup analysis by subspecies, but acknowledge that the prognosis and clinical trajectory of pwCF infected with different NTM may not be similar. We downgraded the certainty of the evidence due to non-randomised study design and serious risk of bias across all studies. We assessed all identified evidence as of very low certainty, such that lung transplant may have little to no effect on any of the outcomes listed below, but the evidence is very uncertain. Mortality Two studies (18 participants with NTM) reported similar survival data between NTM-positive LTx recipients and matched controls without NTM. Another study (9 participants) reported that two of five participants NTM-positive at LTx died within a few months post-LTx, whilst one of four NTM-negative participants died three years post-LTx due to chronic rejection. One study (177 participants) found that pwCF who had positive NTM cultures pre-LTx had a longer median survival duration than those who had negative cultures. This study additionally reported on survival of participants with post-LTx NTM infection, finding that the five participants who had post-LTx NTM disease had a longer mean survival duration than the 141 participants without post-LTx NTM disease. Disseminated NTM infection post-LTx In the largest study, of the 18 pwCF with NTM at the time of LTx, seven had at least one positive NTM culture, and four developed NTM disease post-LTx. Conversely, 79 of the 89 pwCF without NTM remained so post-LTx; 10 participants recorded a positive NTM culture, but none developed NTM disease. For the 39 participants without a baseline NTM culture, three participants recorded positive NTM cultures post-LTx, and one developed NTM disease. Of the remaining small studies, one reported that NTM was isolated in four of 13 participants at LTx and in three of these post-LTx. A second study reported that one out of five pwCF had NTM infection post-LTx (all were positive at LTx). The third study reported that five out of nine participants had NTM disease at LTx, and two of these five remained NTM-positive post-LTx. CLAD Two studies assessed CLAD. One study reported that none of the five NTM-positive LTx recipients developed CLAD, stating that the risk of CLAD appeared to be similar between the NTM and the comparator group. The second study stated that three out of nine LTx recipients with NTM disease developed chronic rejection or graft dysfunction. AUTHORS' CONCLUSIONS:There are no randomised trials to guide clinicians and patients or their families when making decisions regarding LTx in pwCF with NTM. The available data come from observational studies and registry data, often with few people with NTM reported. It has not been possible to pool the available data in meta-analysis, and we are very uncertain of the effect of NTM on pwCF undergoing LTx on the risk of developing NTM disease post-LTx, survival after LTx, and the development of CLAD. The studies were small and at times contradictory. In the era of highly effective modulator treatments, as some centres do not offer LTx to people with a history of NTM, there is an urgent need for more data to guide decision-making. FUNDING:This review is part of a suite of reviews on NTM funded jointly by the CF Foundation and the CF Trust. REGISTRATION:Protocol registration (2024): www.crd.york.ac.uk/PROSPERO/view/562682.

BACKGROUND:The terminal ileum (TI) is commonly affected in people with cystic fibrosis (pwCF), but limited quantitative information is available on its appearance and dimensions. This study aimed to use magnetic resonance imaging (MRI) to: 1) measure the diameter of the distal TI in healthy volunteers (HVs) and pwCF; 2) test the hypothesis that the diameter of the TI in pwCF is larger than in HVs. METHODS:Twenty-six adult pwCF (23 on modulators) and 30 HVs participated. A commercial image analysis platform (Entrolytics, Motilent, UK) was used to measure the long and short axes diameters of the TI on cross-sectional images, along the most distal 5 cm before the ileo-caecal valve. The cross-sectional area of the TI was calculated assuming an elliptical shape. RESULTS:(mean±SD) pwCF had a larger TI compared with HVs: the long axis TI diameter (1.6 ± 0.3 cm for HVs versus 2.7 ± 0.7 cm for pwCF, p < 0.0001), the short axis TI diameter (1.2 ± 0.3 cm versus 2.2 ± 0.6 cm respectively, p < 0.0001) and the TI cross-sectional area (1.6 ± 0.7cm2 versus 4.9 ± 2.5cm2 respectively, p < 0.0001). Sixty-five% of pwCF showed heterogeneous, faeces-like chyme presence in the TI. CONCLUSIONS:This study showed that the TI is enlarged and filled with heterogeneous, faeces-like chyme in pwCF compared with HVs. These findings are in keeping with earlier surgical reports. Increased chyme viscosity and/or impaired motility may lead to accumulation of chyme in the TI in pwCF. New treatments correcting these abnormalities such as secretagogues could be evaluated using the new MRI-derived TI diameter and area endpoints.

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.

Background Gastrointestinal symptoms in cystic fibrosis (CF) are common and intrusive to daily life. Relieving gastrointestinal symptoms was identified as an important research priority and previously explored in an international survey in 2018. However, following the widespread introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators in 2019, the landscape of CF treatment has changed. We repeated an online survey to further describe gastrointestinal symptoms and their effect on quality of life (QoL) in the CFTR modulator era. Methods An electronic survey consisting of closed questions and free text responses was distributed via social media and professional networks for a period of one month between March - April 2022. People with CF (pwCF), their family and friends, and healthcare professionals (HCPs) were invited to take part. Results There were 164 respondents: 88 pwCF (54%), 22 (13%) family, and 54 (33%) healthcare professionals (HCPs). A total of 89/110 (81%) pwCF or family members reported CFTR modulator treatment. The most commonly reported symptoms were wind / gas and rumbling stomach noises (borborygmi) in both the modulator and non-modulator groups in addition to loose motions (modulator group) and bloating (no modulator group). Abdominal pain and bloating had the greatest impact on QoL. For those on a CFTR modulator, the proportion of pwCF reporting “no change” or “worse” for all of the symptoms surveyed was greater than the proportion reporting an improvement. For some symptoms such as stomach pains and reduced appetite, improvements were perceived more commonly in HCPs than what was reported by pwCF. Following modulator introduction, dietary changes to manage GI symptoms were recommended by 28/35 (80%) of HCPs and reported by 38/76 (50%) lay respondents. Changes in medication were recommended by 19/35 (54%) HCPs and reported by 44/76 (58%) of patients and family members. Conclusion This survey has shown that gastrointestinal symptoms remain prevalent in pwCF in the CFTR modulator era, though the nature of these symptoms may have changed. A better understanding of the underlying pathophysiology of these symptoms is essential. Future clinical studies should focus on improving symptoms and QoL.

BackgroundThere is a paucity of knowledge on the longer-term effects of CF transmembrane conductance regulator (CFTR) modulator therapies upon the gut microbiome and associated outcomes. In a pilot study, we investigated longitudinal Elexacaftor/Tezacaftor/Ivacaftor (ETI) therapy on the gut microbiota, metabolomic functioning, and clinical outcomes in people with CF (pwCF).Study designFaecal samples from 20 pwCF were acquired before and then following 3, 6, and 17+ months of ETI therapy. Samples were subjected to microbiota sequencing and targeted metabolomics to profile and quantify short-chain fatty acid composition. Ten healthy matched controls were included for comparison. Clinical data, including markers of intestinal function were integrated to investigate relationships.ResultsExtended ETI therapy increased core microbiota diversity and composition, which translated to gradual shifts in whole microbiota composition towards that observed in healthy controls. Despite becoming more similar over time, CF microbiota and functional metabolite compositions remained significantly different to healthy controls. Antibiotic treatment for pulmonary infection significantly explained a relatively large degree of variation within the whole microbiota and rarer satellite taxa. Clinical outcomes were not significantly different following ETI.ConclusionsWhilst differences persisted, a positive trajectory towards the microbiota observed in healthy controls was found. We posit that progression was predominately impeded by pulmonary antibiotics administration. We recommend future studies use integrated omics approaches within a combination of long-term longitudinal patient studies and model experimental systems. This will deepen our understanding of the impacts of CFTR modulator therapy and respiratory antibiotic interventions upon the gut microbiome and gastrointestinal pathophysiology in CF.

This is the third in a series of four papers updating the European Cystic Fibrosis Society (ECFS) standards for the care of people with CF. This paper focuses on recognising and addressing CF health issues. The guidance was produced with wide stakeholder engagement, including people from the CF community, using an evidence-based framework. Authors contributed sections, and summary statements which were reviewed by a Delphi consultation. Monitoring and treating airway infection, inflammation and pulmonary exacerbations remains important, despite the widespread availability of CFTR modulators and their accompanying health improvements. Extrapulmonary CF-specific health issues persist, such as diabetes, liver disease, bone disease, stones and other renal issues, and intestinal obstruction. These health issues require multidisciplinary care with input from the relevant specialists. Cancer is more common in people with CF compared to the general population, and requires regular screening. The CF life journey requires mental and emotional adaptation to psychosocial and physical challenges, with support from the CF team and the CF psychologist. This is particularly important when life gets challenging, with disease progression requiring increased treatments, breathing support and potentially transplantation. Planning for end of life remains a necessary aspect of care and should be discussed openly, honestly, with sensitivity and compassion for the person with CF and their family. CF teams should proactively recognise and address CF-specific health issues, and support mental and emotional wellbeing while accompanying people with CF and their families on their life journey.

Background:Gastrointestinal symptoms in cystic fibrosis (CF) are common and intrusive to daily life. Relieving gastrointestinal symptoms was identified as an important research priority and previously explored in an international survey in 2018. However, following the widespread introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators in 2019, the landscape of CF treatment has changed. We repeated an online survey to further describe gastrointestinal symptoms and their effect on quality of life (QoL) in the CFTR modulator era. Methods:An electronic survey consisting of closed questions and free text responses was distributed via social media and professional networks for a period of one month between March - April 2022. People with CF (pwCF), their family and friends, and healthcare professionals (HCPs) were invited to take part. Results:There were 164 respondents: 88 pwCF (54%), 22 (13%) family, and 54 (33%) healthcare professionals (HCPs). A total of 89/110 (81%) pwCF or family members reported CFTR modulator treatment. The most commonly reported symptoms were wind / gas and rumbling stomach noises (borborygmi) in both the modulator and non-modulator groups in addition to loose motions (modulator group) and bloating (no modulator group). Abdominal pain and bloating had the greatest impact on QoL.For those on a CFTR modulator, the proportion of pwCF reporting "no change" or "worse" for all of the symptoms surveyed was greater than the proportion reporting an improvement. For some symptoms such as stomach pains and reduced appetite, improvements were perceived more commonly in HCPs than what was reported by pwCF. Following modulator introduction, dietary changes to manage GI symptoms were recommended by 28/35 (80%) of HCPs and reported by 38/76 (50%) lay respondents. Changes in medication were recommended by 19/35 (54%) HCPs and reported by 44/76 (58%) of patients and family members. Conclusion:This survey has shown that gastrointestinal symptoms remain prevalent in pwCF in the CFTR modulator era, though the nature of these symptoms may have changed. A better understanding of the underlying pathophysiology of these symptoms is essential. Future clinical studies should focus on improving symptoms and QoL.

The major cause of mortality in people with cystic fibrosis (pwCF) is progressive lung disease characterised by acute and chronic infections, the accumulation of mucus, airway inflammation, structural damage and pulmonary exacerbations. The prevalence of Pseudomonas aeruginosa rises rapidly in the teenage years, and this organism is the most common cause of chronic lung infection in adults with cystic fibrosis (CF). It is associated with an accelerated decline in lung function and premature death. New P. aeruginosa infections are treated with antibiotics to eradicate the organism, while chronic infections require long-term inhaled antibiotic therapy. The prevalence of P. aeruginosa infections has decreased in CF registries since the introduction of CF transmembrane conductance regulator modulators (CFTRm), but clinical observations suggest that chronic P. aeruginosa infections usually persist in patients receiving CFTRm. This indicates that pwCF may still need inhaled antibiotics in the CFTRm era to maintain long-term control of P. aeruginosa infections. Here, we provide an overview of the changing perceptions of P. aeruginosa infection management, including considerations on detection and treatment, the therapy burden associated with inhaled antibiotics and the potential effects of CFTRm on the lung microbiome. We conclude that updated guidance is required on the diagnosis and management of P. aeruginosa infection. In particular, we highlight a need for prospective studies to evaluate the consequences of stopping inhaled antibiotic therapy in pwCF who have chronic P. aeruginosa infection and are receiving CFTRm. This will help inform new guidelines on the use of antibiotics alongside CFTRm.

BackgroundRelieving gastrointestinal symptoms is a research priority in cystic fibrosis. Emerging evidence highlights effects of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on gastrointestinal function, including pancreatic sufficiency. This study explores ivacaftor licensing and treatment on recorded pancreatic enzyme replacement therapy (PERT) prescription in the US and UK CF registries.MethodsRetrospective longitudinal registry study of recorded pancreatic PERT use between 2008 and 2017. Interrupted time series analysis in propensity-matched cohorts estimated annual change and step change according to ivacaftor eligibility before and after licensing year, 2012. Generalised estimating equations assessed adjusted risk of PERT use in individuals treated with ivacaftor after 2012 compared to untreated individuals.ResultsIn the US CF registry, the difference in annual change in prevalence of PERT use post-2012 between eligible cases and ineligible controls was -5.0 per 1000 people/year (95 %CI -7.6; -2.3, p = 0.001). The step change and annual change in prevalence of PERT use in eligible cases was not significantly different to controls in the UK CF registry. Relative to the relationship in 2013, ivacaftor treatment in the US CF registry was associated with a lower adjusted risk ratio of PERT use compared to untreated individuals by 2016 (0.97, 95 %CI 0.96; 0.99), which was not observed in the UK CF registry.ConclusionsLicensing of ivacaftor was followed by a lower prevalence of PERT use in the eligible US population compared to pre-licensing period, as well as lower risk of PERT use in those who received treatment. Inconsistencies in US and UK CF registries were observed.

Background People with cystic fibrosis (CF) can experience recurrent chest infections, pancreatic exocrine insufficiency and gastrointestinal symptoms. New cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs improve lung function but gastrointestinal effects are unclear. We aimed to see if a CFTR modulator (tezacaftor-ivacaftor,TEZ/IVA) improves gastrointestinal outcomes in CF. Methods We conducted a randomised, double-blind, placebo-controlled, two-period crossover trial (2019-2020) at Nottingham University Hospitals. The effects of TEZ/IVA on gut physiology were measured using MRI. Participants were randomly assigned to treatment sequences AB or BA (A:TEZ/IVA, B:placebo, each 28 days), with a 28-day washout period. Participants had serial MRI scans at baseline and after 19-23 days of each treatment. Due to the COVID-19 pandemic, a protocol amendment allowed for observer-blind comparisons prior to and during TEZ/IVA. In such cases, participants were not blind to the treatment but researchers remained blind. The primary outcome was oro-caecal transit time (OCTT). Secondary outcomes included MRI metrics, symptoms and stool biomarkers. Results We randomised 13 participants. Before the COVID-19 pandemic 8 participants completed the full protocol and 1 dropped out. The remaining 4 participants followed the amended protocol. There were no significant differences between placebo and TEZ/IVA for OCTT (TEZ/IVA >360minutes [225,>360] vs. placebo 330minutes [285,>360], p=0.8) or secondary outcomes. There were no adverse events. Conclusions Our data contribute to a research gap in the extra-pulmonary effects of CFTR modulators. We found no effect after TEZ/IVA on MRI metrics of gut function, GI symptoms or stool calprotectin. Effects might be detectable with larger studies, longer treatment or more effective CFTR modulators. ClinicalTrials.gov registration NCT04006873 (02/07/2019)

This is the final of four papers updating standards for the care of people with CF. That this paper “Planning a longer life” was considered necessary, highlights how much CF care has progressed over the past decade. Several factors underpin this progress, notably increased numbers of people with CF with access to CFTR modulator therapy.As the landscape for CF changes, so do the hopes and aspirations of people with CF and their families. This paper reflects the need to consider people with CF not as a “problem” to be solved, but as a success, a potential and a voice to be heard. People with CF and the wider CF community have driven this approach, reflecting many of the topics in this paper. This exercise involved wide stakeholder engagement. People with CF are keen to contribute to research priorities and be involved in all stages of research. People with CF want healthcare professionals to respect them as individuals and consider the impact of our actions on the world around us.Navigating life presents challenges to all, but for people with CF these challenges are heightened and complex. In this paper we highlight the concerns and life moments that impact people with CF, and events that the CF team should aim to support, including the challenges around having a family.People with CF and their care teams must embrace the updated standards outlined in these four papers to enjoy the full potential for a healthier life.

Background: Gastrointestinal (GI) symptoms in cystic fibrosis (CF) are common and disruptive. The effect of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on the GI tract is not fully understood. The aim was to use magnetic resonance imaging (MRI) to determine if elexacaftor/tezacaftor/ivacaftor (ETI) changed GI function and transit. Methods: This was an 18 month prospective, longitudinal, observational study. We enrolled 24 people with CF aged 12 years or older to undergo MRI scans before starting ETI and 3, 6, and 18 months after starting ETI. The primary outcome measure was change in oro-caecal transit time (OCTT) at 6 and 18 months. Secondary outcome measures included change in small bowel water content (SBWC), change in the reduction in small bowel water content following a meal (DeltaSBWC) and change in total colonic volume (TCV). Results: A total of 21 participants completed MRI scans at 6 months and 11 completed at 18 months. After 18 months of ETI, median OCTT significantly reduced, from >360 min [IQR 240->360] to 240 min [IQR 180-300] (p = 0.02, Wilcoxon signed-rank). Both SBWC and DeltaSBWC increased after starting ETI. TCV reduced significantly after 18 months (p = 0.005, Friedman). Conclusions: Our findings suggest an improvement in small bowel transit, small bowel response to food and a reduction in colonic volume after starting ETI. These effects may relate to CFTR activation in the small bowel. To our knowledge this is the first study to show a physiological change in GI transit and function in response to CFTR modulator use through imaging studies.

Chronic inflammation dominates disease pathogenesis in Cystic Fibrosis (CF) and there is a need to characterise CF immunity. Whole blood cultures offer a cost-effective and non-invasive approach to investigate immune responses within the host environment. Here we used whole blood cultures to investigate the differentiation potential of monocytes (CD45+CD14+ cells) in CF (N=10) and controls (N=8) in the presence and absence of exogenous macrophage-colony stimulatory factor (M-CSF) or granulocyte-macrophage (GM)-CSF with and without interleukin (IL)-4. In CF and control cultures, CD45+CD14+ cells upregulated HLA-DR expression in all instances, and increased CD206 in the presence of GM-CSF with and without IL-4, and CD209 in the presence of GM-CSF and IL-4. In CF, we consistently observed reduced upregulation of CD206 in response to GM-CSF and a positive correlation between CD206 expression and lung function (FEV 1 ). This was unique to cultured monocytes, and not seen with any other marker. These results highlight the potential of whole blood cultures to reveal cellular characteristics in differentiating monocytes related to clinical parameters that could guide the identification of novel biomarkers in CF.

BackgroundRespiratory tract infection with Pseudomonas aeruginosa occurs inmost people with cystic fibrosis. Once chronic infection is established, Pseudomonas aeruginosa is virtually impossible to eradicate and is associated with increased mortality and morbidity. Early infection may be easier to eradicate. This is an update of a Cochrane review first published in 2003, and previously updated in 2006, 2009 and 2014.ObjectivesTo determine whether antibiotic treatment of early Pseudomonas aeruginosa infection in children and adults with cystic fibrosis eradicates the organism, delays the onset of chronic infection, and results in clinical improvement. To evaluate whether there is evidence that a particular antibiotic strategy is superior to or more cost- effective than other strategies and to compare the adverse effects of different antibiotic strategies (including respiratory infection with other micro- organisms).Search methodsWe searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Most recent search: 10 October 2016.Selection criteriaWe included randomised controlled trials of people with cystic fibrosis, in whom Pseudomonas aeruginosa had recently been isolated from respiratory secretions. We compared combinations of inhaled, oral or intravenous antibiotics with placebo, usual treatment or other combinations of inhaled, oral or intravenous antibiotics. We excluded non- randomised trials, cross- over trials, and those utilising historical controls.Data collection and analysisBoth authors independently selected trials, assessed risk of bias and extracted data.Main resultsThe search identified 60 trials; seven trials (744 participants) with a duration between 28 days and 27months were eligible for inclusion. Three of the trials are over 10 years old and their results may be less applicable today given the changes in standard treatment. Some of the trials had low numbers of participants and most had relatively short follow-up periods; however, there was generally a low risk of bias from missing data. In most trials it was difficult to blind participants and clinicians to treatment given the interventions and comparators used. Two trials were supported by the manufacturers of the antibiotic used.Evidence from two trials (38 participants) at the two-month time-point showed treatment of early Pseudomonas aeruginosa infection with inhaled tobramycin results in microbiological eradication of the organism from respiratory secretions more often than placebo, odds ratio 0.15 (95% confidence interval (CI) 0.03 to 0.65) and data from one of these trials, with longer follow up, suggested that this effect may persist for up to 12 months.One randomised controlled trial (26 participants) compared oral ciprofloxacin and nebulised colistin versus usual treatment. Results after two years suggested treatment of early infection results in microbiological eradication of Pseudomonas aeruginosa more often than no anti-pseudomonal treatment, odds ratio 0.12 (95% CI 0.02 to 0.79).One trial comparing 28 days to 56 days treatment with nebulised tobramycin solution for inhalation in 88 participants showed that both treatments were effective and well-tolerated, with no notable additional improvement with longer over shorter duration of therapy. However, this trial was not powered to detect non-inferiority or equivalence.A trial of oral ciprofloxacin with inhaled colistin versus nebulised tobramycin solution for inhalation alone (223 participants) failed to show a difference between the two strategies, although it was underpowered to show this. A further trial of inhaled colistin with oral ciprofloxacin versus nebulised tobramycin solution for inhalation with oral ciprofloxacin also showed no superiority of the former, with increased isolation of Stenotrophomonas maltophilia in both groups.A recent, large trial in 306 children aged between one and 12 years compared cycled nebulised tobramycin solution for inhalation to culture-based therapy and also ciprofloxacin to placebo. The primary analysis showed no difference in time to pulmonary exacerbation or proportion of Pseudomonas aeruginosa positive cultures. An analysis performed in this review (not adjusted for age) showed fewer participants in the cycled therapy group with one or more isolates of Pseudomonas aeruginosa, odds ratio 0.51 (95% CI 0.31 to 0.28).Using GRADE, the quality of evidence for outcomes was downgraded tomoderate to very low. Downgrading decisions for Pseudomonas aeruginosa eradication and lung function were based on applicability (participants mostly children) and limitations in study design, with imprecision an additional limitation for lung function, growth parameters and adverse effects.Authors' conclusionsWe found that nebulised antibiotics, alone or in combination with oral antibiotics, were better than no treatment for early infection with Pseudomonas aeruginosa. Eradication may be sustained for up to two years. There is insufficient evidence to determine whether antibiotic strategies for the eradication of early Pseudomonas aeruginosa decrease mortality or morbidity, improve quality of life, or are associated with adverse effects compared to placebo or standard treatment. Four trials comparing two active treatments have failed to show differences in rates of eradication of Pseudomonas aeruginosa. There have been no published randomised controlled trials that investigate the efficacy of intravenous antibiotics to eradicate Pseudomonas aeruginosa in cystic fibrosis. Overall, there is still insufficient evidence from this review to state which antibiotic strategy should be used for the eradication of early Pseudomonas aeruginosa infection in cystic fibrosis.

People with cystic fibrosis (pwCF) experience a range of persistent gastrointestinal symptoms throughout life. There is evidence indicating interaction between the microbiota and gut pathophysiology in CF. However, there is a paucity of knowledge on the potential effects of CF transmembrane conductance regulator (CFTR) modulator therapies on the gut microbiome. In a pilot study, we investigated the impact of Tezacaftor/Ivacaftor dual combination CFTR modulator therapy on the gut microbiota and metabolomic functioning in pwCF. Fecal samples from 12 pwCF taken at baseline and following placebo or Tezacaftor/Ivacaftor administration were subjected to microbiota sequencing and to targeted metabolomics to assess the short-chain fatty acid (SCFA) composition. Ten healthy matched controls were included as a comparison. Inflammatory calprotectin levels and patient symptoms were also investigated. No significant differences were observed in overall gut microbiota characteristics between any of the study stages, extended also across intestinal inflammation, gut symptoms, and SCFA-targeted metabolomics. However, microbiota and SCFA metabolomic compositions, in pwCF, were significantly different from controls in all study treatment stages. CFTR modulator therapy with Tezacaftor/Ivacaftor had negligible effects on both the gut microbiota and SCFA composition across the course of the study and did not alter toward compositions observed in healthy controls. Future longitudinal CFTR modulator studies will investigate more effective CFTR modulators and should use prolonged sampling periods, to determine whether longer-term changes occur in the CF gut microbiome. IMPORTANCE People with cystic fibrosis (pwCF) experience persistent gastrointestinal (GI) symptoms throughout life. The research question "how can we relieve gastrointestinal symptoms, such as stomach pain, bloating, and nausea?" remains a top priority for clinical research in CF. While CF transmembrane conductance regulator (CFTR) modulator therapies are understood to correct underlying issues of CF disease and increasing the numbers of pwCF are now receiving some form of CFTR modulator treatment. It is not known how these therapies affect the gut microbiome or GI system. In this pilot study, we investigated, for the first time, effects of the dual combination CFTR modulator medicine, Tezacaftor/Ivacaftor. We found it had negligible effects on patient GI symptoms, intestinal inflammation, or gut microbiome composition and functioning. Our findings are important as they fill important knowledge gaps on the relative effectiveness of these widely used treatments. We are now investigating triple combination CFTR modulators with prolonged sampling periods.