Predominant pathogen competition and core microbiota divergence in chronic airway infection

© 2015 International Society for Microbial Ecology All rights reserved. Chronic bacterial lung infections associated with non-cystic fibrosis bronchiectasis represent a substantial and growing health-care burden. Where Pseudomonas aeruginosa is the numerically dominant species within these infections, prognosis is significantly worse. However, in many individuals, Haemophilus influenzae predominates, a scenario associated with less severe disease. The mechanisms that determine which pathogen is most abundant are not known. We hypothesised that the distribution of H. influenzae and P. aeruginosa would be consistent with strong interspecific competition effects. Further, we hypothesised that where P. aeruginosa is predominant, it is associated with a distinct 'accessory microbiota' that reflects a significant interaction between this pathogen and the wider bacterial community. To test these hypotheses, we analysed 16S rRNA gene pyrosequencing data generated previously from 60 adult bronchiectasis patients, whose airway microbiota was dominated by either P. aeruginosa or H. influenzae. The relative abundances of the two dominant species in their respective groups were not significantly different, and when present in the opposite pathogen group the two species were found to be in very low abundance, if at all. These findings are consistent with strong competition effects, moving towards competitive exclusion. Ordination analysis indicated that the distribution of the core microbiota associated with each pathogen, readjusted after removal of the dominant species, was significantly divergent (analysis of similarity (ANOSIM), R=0.07, P=0.019). Taken together, these findings suggest that both interspecific competition and also direct and/or indirect interactions between the predominant species and the wider bacterial community may contribute to the predominance of P. aeruginosa in a subset of bronchiectasis lung infections

Bronchiectasis insanity:Doing the same thing over and over again and expecting different results?

Bronchiectasis is an increasingly common disease with a significant impact on quality of life and morbidity of affected patients. It is also a very heterogeneous disease with numerous different underlying etiologies and presentations. Most treatments for bronchiectasis are based on low-quality evidence; consequently, no treatments have been approved by the US Food and Drug Administration or the European Medicines Agency for the treatment of bronchiectasis. The last several years have seen numerous clinical trials in which the investigational agent, thought to hold great promise, did not demonstrate a clinically or statistically significant benefit. This commentary will review the likely reasons for these disappointing results and a potential approach that may have a greater likelihood of defining evidence-based treatment for bronchiectasis

Multidimensional severity assessment in bronchiectasis:An analysis of 7 European cohorts.

INTRODUCTION: Bronchiectasis is a multidimensional disease associated with substantial morbidity and mortality. Two disease-specific clinical prediction tools have been developed, the Bronchiectasis Severity Index (BSI) and the FACED score, both of which stratify patients into severity risk categories to predict the probability of mortality. METHODS: We aimed to compare the predictive utility of BSI and FACED in assessing clinically relevant disease outcomes across seven European cohorts independent of their original validation studies. RESULTS: The combined cohorts totalled 1612. Pooled analysis showed that both scores had a good discriminatory predictive value for mortality (pooled area under the curve (AUC) 0.76, 95% CI 0.74 to 0.78 for both scores) with the BSI demonstrating a higher sensitivity (65% vs 28%) but lower specificity (70% vs 93%) compared with the FACED score. Calibration analysis suggested that the BSI performed consistently well across all cohorts, while FACED consistently overestimated mortality in 'severe' patients (pooled OR 0.33 (0.23 to 0.48), p<0.0001). The BSI accurately predicted hospitalisations (pooled AUC 0.82, 95% CI 0.78 to 0.84), exacerbations, quality of life (QoL) and respiratory symptoms across all risk categories. FACED had poor discrimination for hospital admissions (pooled AUC 0.65, 95% CI 0.63 to 0.67) with low sensitivity at 16% and did not consistently predict future risk of exacerbations, QoL or respiratory symptoms. No association was observed with FACED and 6 min walk distance (6MWD) or lung function decline. CONCLUSION: The BSI accurately predicts mortality, hospital admissions, exacerbations, QoL, respiratory symptoms, 6MWD and lung function decline in bronchiectasis, providing a clinically relevant evaluation of disease severity

Enzyme replacement therapy for mucopolysaccharidosis VI: evaluation of long-term pulmonary function in patients treated with recombinant human N-acetylgalactosamine 4-sulfatase

Pulmonary function is impaired in untreated mucopolysaccharidosis type VI (MPS VI). Pulmonary function was studied in patients during long-term enzyme replacement therapy (ERT) with recombinant human arylsulfatase B (rhASB; rhN-acetylgalactosamine 4-sulfatase). Pulmonary function tests prior to and for up to 240 weeks of weekly infusions of rhASB at 1 mg/kg were completed in 56 patients during Phase 1/2, Phase 2, Phase 3 and Phase 3 Extension trials of rhASB and the Survey Study. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and, in a subset of patients, maximum voluntary ventilation (MVV), were analyzed as absolute volume in liters. FEV1 and FVC showed little change from baseline during the first 24 weeks of ERT, but after 96 weeks, these parameters increased over baseline by 11% and 17%, respectively. This positive trend compared with baseline continued beyond 96 weeks of treatment. Improvements from baseline in pulmonary function occurred along with gains in height in the younger group (5.5% change) and in the older patient group (2.4% change) at 96 weeks. Changes in MVV occurred earlier within 24 weeks of treatment to approximately 15% over baseline. Model results based on data from all trials showed significant improvements in the rate of change in pulmonary function during 96 weeks on ERT, whereas little or no improvement was observed for the same time period prior to ERT. Thus, analysis of mean percent change data and longitudinal modeling both indicate that long-term ERT resulted in improvement in pulmonary function in MPS VI patients

Digitized narratives of sexual violence: Making sexual violence felt and known through digital disclosures

In this article, we argue that social media platforms like Tumblr and Twitter have facilitated an emergence of “digitized narratives” of sexual violence. These narratives are rooted in historical ways in which feminists have discursively articulated sexual violence, yet are shaped by distinctive “platform vernacular” or the conventions, affordances, and restrictions of the platforms in which they appear. Drawing on a qualitative content and critical discourse analysis of 450 texts from the Tumblr site Who Needs Feminism? and the hashtag #BeenRapedNeverReported, we argue that digital platforms such as Tumblr and Twitter produce new vernacular practices which shape how “digitized narratives” of sexual violence are not only disclosed and known, but felt and experienced across digital networks

Inhaled antibiotics for lower respiratory tract infections: focus on ciprofloxacin

The administration of antibiotics by the inhaled route offers an appealing and logical approach to treating infectious respiratory conditions. Studies in the cystic fibrosis (CF) population have established the efficacy of this therapeutic concept and inhaled antibiotic therapy is now one of the pillars of management in CF. There are now a number of new inhaled antibiotic formulations that have shown impressive preliminary evidence for efficacy in CF and are commencing phase III efficacy studies. Translation of this paradigm into the non-CF bronchiectasis population has proven difficult thus far, apparently due to problems with tolerability of inhaled formulations. Inhaled versions of ciprofloxacin have shown good tolerability and microbiological efficacy in preliminary studies, suggesting that effective inhaled antibiotics are finally on the horizon for this previously neglected patient population. The increased use of long-term inhaled antibiotics for a wider range of non-CF indications presents risks to the broader community of greater antimicrobial resistance development that must be carefully weighed against any demonstrated benefits