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Pseudomonas aeruginosa is the main cause of chronic airway infection in cystic fibrosis (CF). However, for unclear reasons some patients are never colonized by P. aeruginosa. The objectives of this study were to better define the clinical, genetic, and microbiological characteristics of such a subpopulation and to identify predictive factors of non-colonization with P. aeruginosa. The French CF patient registry 2013-2014 was used to identify CF patients aged ≥ 20 years. The clinical outcomes, CF Transmembrane conductance Regulator (CFTR) genotypes, and microbiological data of patients reported positive at least once for P. aeruginosa ("Pyo" group, n = 1,827) were compared to those of patients with no history of P. aeruginosa isolation ("Never" group, n = 303). Predictive factors of non-colonization by P. aeruginosa were identified by multivariate logistic regression model with backward selection. Absence of aspergillosis (odds ratio (OR) [95% CI] = 1.64 [1.01-2.66]), absence of diabetes (2.25 [1.21-4.18]), pancreatic sufficiency (1.81 [1.30-2.52]), forced expiratory volume 1 (FEV1) ≥ 80% (3.03 [2.28-4.03]), older age at CF diagnosis (1.03 [1.02-1.04]), and absence of F508del/F508del genotype (2.17 [1.48-3.19]) were predictive clinical factors associated with absence of infection ("Never" group). Microbiologically, this same group was associated with more frequent detection of Haemophilus influenzae and lower rates of Stenotrophomonas maltophilia, Achromobacter xylosoxidans and Aspergillus spp. (all p

BackgroundDiagnosis of Mycobacterium tuberculosis (MTB) infection can be confirmed by Xpert assays within hours. However, when sample size does not allow performing both culture and Xpert, or if Xpert is negative, then formal diagnosis of MTB relies on culture and time to detection of growth (TDG) becomes critical for clinical management.ObjectivesTo determine TDG in Xpert negative samples, or in samples in which Xpert could not be performed, in a low-incidence area for MTB.MethodsRetrospective analysis (2015-2020) of a database including all cultures for mycobacteria in a University Hospital covering approximately 500’000 inhabitants. Analysis was restricted to culture positive (C+) samples for MTB for which 1/Xpert was negative or could not be performed because of limited sample volume, and 2/collected from subjects treated less than 24 hours. TDG was analyzed according to microscopy, origin of sample (pulmonary or not) and presence of cavitation.ResultsAmong 837 C+ samples for MTB, 236 samples (80% of respiratory origin) from 147 patients fulfilled study criteria; 78 samples (49 patients, 33%) were acid-fast bacilli (AFB) positive. Median (IQR) TDG was 25 (17; 40) days for all samples. TDG exceeded 28 days in 43% of samples and was significantly shorter in AFB+ vs AFB- samples, and samples from cavitary vs non cavitary or extra-thoracic disease.ConclusionsIn Xpert negative samples, or samples for which Xpert could not be performed, TDG exceeded 4 weeks in 43% of samples. AFB+ and samples from cavitary lung disease had a significantly shorter TDG.

Abstract Allergic mechanisms related to environmental and occupational exposure have been suggested to contribute to the development of chronic obstructive pulmonary disease (COPD). Objectives To investigate the relationships between atopy markers, persistent airflow limitation (PAL) and occupational exposure in dairy farmers. Methods Clinical and biological (total IgE and 21 allergen specific IgE) markers of atopy were assessed in 101 dairy farmers with PAL (DF-PAL), 85 non-farmers with PAL (NF-PAL) (both groups were prospectively included from a screening program performed between 2011 and 2015), and matched controls, i.e. 98 farmers without PAL (DF-controls) and 89 non-farming subjects without PAL (NF-controls). Occupational exposure in farmers was estimated using a validated questionnaire. Results Prevalence of allergy history was significantly higher in DF-PAL and in NF-PAL than in controls. Polysensitization, and sensitization to seasonal and food allergens were more frequent in DF-PAL than in DF-controls, respectively: 13.8% vs 1% (adjusted odds ratio (aOR): 17.5 (2.2–134), 11.9% vs 3.1% (aOR: 4.4 (1.2–7.2) and 16.8% vs 4.1% (aOR: 5.2 (1.7–7.2)). The prevalence of atopy markers was similar between NF-PAL patients and NF-controls. Conclusions PAL in farmers is associated with a high rate of markers of atopy, supporting atopy as a risk indicator. Clinical trial registered with ClinicalTrials.gov (NCT02540408).