Aspergillus fumigatus is commonly found in the respiratory secretions of patients with cystic fibrosis (CF). Although allergic bronchopulmonary aspergillosis (ABPA) is associated with deterioration of lung function, the effects of A. fumigatus colonization on lung function in the absence of ABPA are not clear. This study was performed in 259 adults and children with CF, without ABPA. A. fumigatus colonization was defined as positivity of >50% of respiratory cultures in a given year. A cross-sectional analysis was performed to study clinical characteristics associated with A. fumigatus colonization. A retrospective cohort analysis was performed to study the effect of A. fumigatus colonization on lung function observed between 2002 and 2007. Longitudinal data were analysed with a linear mixed model. Sixty-one of 259 patients were at least intermittently colonized with A. fumigatus. An association was found between A. fumigatus colonization and increased age and use of inhaled antibiotics. In the longitudinal analysis, 163 patients were grouped according to duration of colonization. After adjustment for confounders, there was no significant difference in lung function between patients colonized for 0 or 1 year and patients with 2-3 or more than 3 years of colonization (p 0.40 and p 0.64) throughout the study. There was no significant difference in lung function decline between groups. Although colonization with A. fumigatus is more commonly found in patients with more severe lung disease and increased treatment burden, it is not independently associated with lower lung function or more severe lung function decline over a 5-year period.
The patient-to-patient transmission of highly prevalent Pseudomonas aeruginosa clones which are associated with enhanced disease progression has led to strict segregation policies for cystic fibrosis (CF) patients in many countries. However, little is known about the population structure of P. aeruginosa among CF patients. The aim of the present cross-sectional study was to determine the prevalence and genetic relatedness of P. aeruginosa isolates from CF patients who visited two major CF centers in The Netherlands in 2007 and 2008. These patients represented 45% of the Dutch CF population. P. aeruginosa carriage in the respiratory tract was determined by standard microbiological culture techniques, and all phenotypically different isolates in the first specimens recovered in 2007 and 2008 were genotyped by multilocus sequence typing. A total of 313 (57%) of 551 patients whose samples were cultured carried P. aeruginosa. Two sequence types (STs), ST406 and ST497, were found in 15% and 5% of the patients, respectively, and 60% of the patients harbored a strain that was also found in at least two other patients. The risk ratios for carrying ST406 and ST497 were 17.8 (95% confidence interval [CI], 7.2 to 43.6) for those aged between 15 and 24 years and 6 (95% CI, 1.4 to 26.1) for those aged >25 years. ST406 and ST497 were not genetically linked to previously described epidemic clones, which were also not found in this CF population. The population structure of P. aeruginosa in Dutch CF patients is characterized by the presence of two prevalent STs that are associated with certain age groups and that are not genetically linked to previously described epidemic clones.Pseudomonas aeruginosa is a ubiquitous, versatile bacterium that can infect humans as well as plants and animals. The species is infamous for causing nosocomial infections in immunocompromised patients and patients in intensive care units and is a major cause of morbidity and mortality in patients with cystic fibrosis (CF) (26).The widely held belief that CF patients acquire P. aeruginosa strains mainly from their inanimate environment, with most patients being colonized by unique strains, has been challenged by reports indicating that P. aeruginosa clones may frequently be transmitted between CF patients (3,6,18,19,23,24). Some of these clones, such as the Liverpool epidemic strain and the Melbourne epidemic strain, have been associated with enhanced disease progression and higher rates of mortality, respectively (1, 13). In The Netherlands, the patient-to-patient transmission of P. aeruginosa was documented during a summer camp (4). These findings have led to strict segregation policies for CF patients in many countries, including The Netherlands. However, despite these studies, there is little information on the population structure of P. aeruginosa within populations of CF patients. We therefore investigated the prevalence and genetic relatedness of P. aeruginosa isolates compared to those of the international known genotypes in an unbiased cohort re...
Background: Serological methods to monitor Pseudomonas aeruginosa colonisation in patients with cystic fibrosis (CF) are advocated but the diagnostic value of a commercially available P aeruginosa antibody test to detect early and chronic P aeruginosa colonisation in a non-research setting has not been assessed. Methods: Colonisation with P aeruginosa was estimated by regular culture of sputum or oropharyngeal swabs during three consecutive years in 220 patients with CF aged 0-65 years. Commercially available ELISA tests with three P aeruginosa antigens (elastase, exotoxin A, alkaline protease) were performed at the end of the study period. In a subgroup of 57 patients (aged 4-14 years) serological tests were performed annually. Results: Using culture as the reference standard, the ELISA tests using the advised cut off values had a sensitivity of 79% and a specificity of 89% for chronic colonisation. Receiver-operator characteristic curves were created to optimise cut off values. Applying these new cut off values resulted in a sensitivity of 96% and a specificity of 79%. All three individual serological tests discriminated well between the absence and presence of chronic P aeruginosa colonisation. The sensitivity of the individual antibody test was 87% for elastase, 79% for exotoxin A, and 76% for alkaline protease. First colonisation was preceded by positive serological results in only five of 13 patients (38%). Conclusion: In patients with CF, serological tests using specific antigens are sensitive for diagnosing chronic P aeruginosa colonisation. However, the failure of serological tests to detect early colonisation in young patients emphasises the need for continued reliance on cultures.
Do physicians apply an early-switch strategy (from intravenous to oral antibiotics) in clinically stable patients hospitalised with community-acquired pneumonia (CAP)? If not, why not?In a multicentre prospective cohort study, adult patients admitted for i.v. CAP treatment were included. On day 3 of antibiotic treatment, clinical stability was assessed and treating resident physicians were interviewed on their switch strategies. Additionally, treating physicians were interviewed to evaluate their knowledge of and adherence to guideline advice.149 (92%) out of 162 patients were included and 97 (91%) out of 107 physicians were interviewed. A switch to oral antibiotics was possible in 68 (46%) out of 149 patients on day 3 of treatment but not performed in 27 (40%) out of 68. Patient factors delaying the switch were high CURB-65 (confusion of new onset, urea .7 mmol?L -1 , respiratory rate of o30 breaths?min -1 , blood pressure ,90 mmHg or diastolic blood pressure f60 mmHg, and age o65 yrs) score (on admission) (p50.04) and oxygen treatment (p50.04), high temperature (p50.00) and high respiration rate (p50.04) (day 3). Physicians' barriers to an early switch in clinically stable patients included misconceptions (26 (55%) out of 47), practical considerations (13 (28%) out of 47) and organisational factors (eight (17%) out of 47). Strikingly, 91 (94%) out of 97 interviewed physicians were not aware of guideline advice. The switch from i.v. to oral antibiotics is often unnecessarily delayed in patients hospitalised with CAP due to different types of barriers.
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