Background: The responsiveness of the endurance shuttle walk to functional changes following bronchodilation has recently been reported. The current literature suggests that the 6 min walking test (6MWT) is less responsive to bronchodilation than the endurance shuttle walk. Aim: To compare bronchodilator-induced changes in exercise performance with the 6MWT and the endurance shuttle walk. Methods: In a randomised, double-blind, placebo-controlled, crossover trial, 14 patients with chronic obstructive pulmonary disease (forced expiratory volume in 1 s (FEV 1 ) 50 (8)% predicted) completed two 6MWTs and two endurance shuttle walks, each preceded by nebulised placebo or 500 mg ipratropium bromide. Cardiorespiratory parameters were monitored during each walking test with a portable telemetric gas analyser. Quadriceps twitch force was measured by magnetic stimulation of the femoral nerve before and after each walking test. Results: The 6 min walking distance did not change significantly after bronchodilation despite a significant increase in FEV 1 of 0.18 (0.09) litres (p,0.001). A similar change in FEV 1 (0.18 (0.12) litres, p,0.001) was associated with a significant improvement in the distance walked on the endurance shuttle walk (Ddistance ipratropium bromide -placebo = 144 (219) m, p = 0.03). Quadriceps muscle fatigue was infrequent (,15% of patients) after both walking tests. Conclusion: The endurance shuttle walk is more responsive than the 6MWT for detecting changes in exercise performance following bronchodilation.

The International Pseudomonas aeruginosa Consortium is sequencing over 1000 genomes and building an analysis pipeline for the study of Pseudomonas genome evolution, antibiotic resistance and virulence genes. Metadata, including genomic and phenotypic data for each isolate of the collection, are available through the International Pseudomonas Consortium Database (http://ipcd.ibis.ulaval.ca/). Here, we present our strategy and the results that emerged from the analysis of the first 389 genomes. With as yet unmatched resolution, our results confirm that P. aeruginosa strains can be divided into three major groups that are further divided into subgroups, some not previously reported in the literature. We also provide the first snapshot of P. aeruginosa strain diversity with respect to antibiotic resistance. Our approach will allow us to draw potential links between environmental strains and those implicated in human and animal infections, understand how patients become infected and how the infection evolves over time as well as identify prognostic markers for better evidence-based decisions on patient care.

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