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Background: Nutritional therapy is one of the cornerstones in cystic fibrosis (CF) therapy. There is a strong association between nutritional status and pulmonary function and thus longevity. Therefore nutritional therapy should be continuously adapted to preserve or improve the nutritional status. This narrative review was written to reconsider nutritional therapy in CF based on the latest evidence available since the publication of the ESPEN - ESPGHAN - ECFS guidelines on nutrition care for infants, children and adults with CF., Methods: A literature search in Pubmed, Scopus and Web of Science was conducted to identify new research focusing on the use of growth charts, body composition, protein intake and pancreatic enzyme therapy (PERT) in CF between June 2014 and June 2017., Results: The search strategy resulted in a total of 1810 hits across the databases. After reviewing title and abstract only 17 studies were included of which 2 animal studies. The use of growth charts was discussed in 3 studies, body composition in 6, protein intake and digestion in 4 and PERT in 4., Conclusion: According to the current guidelines and the available evidence of the discussed topics, it is important that the nutritional therapy in CF is redefined according to age, pancreatic function and disease stage. Macronutrients balances are of importance and change over lifetime. As a consequence an accurate PERT intake is required and thus further research on timing and dosage is necessary. To improve the nutritional assessment a proper use of the growth charts and a consensus on body composition measurements, references and thresholds is advised., (Copyright © 2018 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.)

After antibiotic eradication treatment for a first ever Pseudomonas aeruginosa isolation, the European consensus criteria (ECC) are widely used to assess colonization status with P. aeruginosa in CF-patients. We evaluated to what extent genotyping (GT) of subsequent P. aeruginosa isolates could predict/assess chronic colonization (CC), in comparison with the ECC., Methods: Over a 14-year period, sputa were cultured from 80 CF-patients (age range: 2-51 years), from a first ever isolation of P. aeruginosa onwards. Patients with a positive culture for P. aeruginosa received antibiotic eradication treatment. For the 40 patients for whom three or more P. aeruginosa isolates were available, these isolates were genotyped., Results: According to the ECC, 27 out of the 40 patients (67.5%) became CC during the study period (ECC-positive patients). Genotyping confirmed persistence of the same genotype for 25 of these ECC-positive patients. Genotyping indicated persistence of the same genotype for at least two subsequent isolates for 5 out of 13 ECC-negative patients. Culture-positivity characteristics of the 27 ECC-positive patients corresponded well to those of the 30 GT-positive patients, with an overall higher number of positive cultures as well as a shorter interval in between first and second isolate compared to ECC-negative and GT-negative patients. Genotyping indicated persistence of the same genotype on average 9.3 months earlier than CC according to the ECC (P < 0.01)., Conclusions: Genotyping of P. aeruginosa isolates confirmed CC for 25 out of 27 ECC-positive patients (92.6% specificity) and predicted CC 9.3 months earlier than the ECC., (Copyright © 2018 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Background: Allergic bronchopulmonary aspergillosis (ABPA) is a major complication in cystic fibrosis (CF) patients. Risk factors for ABPA and clinical deterioration in CF patients, negative for Pseudomonas aeruginosa (Pa), were explored., Methods: We performed a retrospective case-control study in 73 Pa-negative patients. Each patient was matched with 2 controls for age, gender, pancreas sufficiency, DeltaF508 mutation (homozygous or heterozygous), and Pa colonization., Results: Median FEV 1 at the year of diagnosis (index year) was significantly lower in patients with ABPA. The median of cumulative values of FEV 1 and FVC before the index year was not significantly different. After the index year, the median of cumulative data for FEV 1 and FVC was significantly lower; there were significantly more hospitalization days and more IV antibiotic days compared to controls. Comparing pre- and post-index year data in patients with ABPA, significantly more hospitalization days and more IV antibiotic days were observed after the index year. During the period preceding the index year, significantly more ABPA patients were treated with rhDNase and inhaled corticosteroids., Conclusions: Bronchial damage cannot be considered as a facilitating factor for ABPA. ABPA causes a significant increase in bronchial damage. In patients with ABPA, further bronchial damage can be controlled by an increase in hospitalization days and use of IV antibiotics. rhDNase and inhaled corticosteroids were associated with the development of ABPA., (© 2018 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: Long-term effect of enteral tube feeding (ETF) in cystic fibrosis (CF) remains equivocal., Methods: A Belgian CF registry based, retrospective, longitudinal study, evaluated the pre- and post- ETF (n = 113) clinical evolution and compared each patient with 2 age, gender, pancreatic status and genotype class-matched controls., Results: At baseline ETF had a worse BMI z-score (p < 0.0001) and FEV1% (p < 0.0001) compared to controls. Patients eventually receiving ETF, had already a significant worse nutritional status and pulmonary function at first entry in the registry. Both parameters displayed a significant decline before ETF-introduction. ETF had more hospitalization and intravenous antibiotic (IVAB) treatment days (p < 0.0001). After ETF introduction hospitalizations and IVAB decreased significantly. After ETF-introduction BMI z-score recuperated towards the original curve before the decline, but remained below the controls. Starting ETF had no effect on rate of height gain in children. The pre-index FEV1 decline (-1.52%/year (p = 0.002)) stabilized to +0.39%/year afterwards. Controls displayed decline of -0.48%/year (p < 0.0001)., Conclusion: ETF introduction improved BMI z-score and stabilized FEV1, associated with less hospitalizations and IVAB treatments. Higher mortality and transplantation in the ETF cases, leading to drop-outs, made determination of the effect size difficult., (Copyright © 2018 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

This study evaluates the impact of antibiotic treatments and hospitalization on exercise performance and health-related quality of life (QOL) in children with mild cystic fibrosis (CF) lung disease. Forty-seven children between 7 and 17 years with mild CF underwent a maximal exercise test including spiro-ergometry and filled out a QOL-questionnaire (PedsQL™). Amount of antibiotic treatments (AB) and hospitalization days in the last 3 years were reviewed. FEV1% was mildly decreased (91.7 ± 17.9 L/min, p = 0.02). Maximal oxygen consumption (VO 2 max), test duration and anaerobic threshold were lower compared to a control population (VO 2 max% 94 ± 15 vs 103 ± 13, p = 0.009). FEV1% correlated with AB and hospitalization episodes in the last year and 3 years before testing, VO 2 max% only correlated with AB in the last 3 years. Domains of school functioning and emotional functioning were low. Children with higher VO 2 max% and less AB in the last 3 years had better physical health. Physical health and school functioning were negatively correlated with hospitalization days in the last year., Conclusion: Patients with mild CF lung disease have good exercise performance although still lower than the normal population. VO2max% is affected by number of antibiotic treatments over a longer period. There is an impact of hospitalization days on quality of life. What is Known: • Children with CF have lower exercise performance; there is an association between hospitalization frequency and exercise performance • Quality of life is diminished in children with CF and influenced by respiratory infections What is New: • Even patients with mild CF lung disease have lower maximal exercise performance (VO 2 max) and a lower anaerobic threshold; VO 2 max is lower in children who had more antibiotic treatments in the last 3 years • School and emotional functioning are diminished in children with mild CF lung disease; hospitalization is negatively correlated with school functioning and physical functioning.

Background: Achromobacter xylosoxidans is increasingly being recognized as an emerging pathogen in cystic fibrosis. Recent severe infections with A. xylosoxidans in some of our cystic fibrosis (CF) patients led to a re-evaluation of the epidemiology of CF-associated A. xylosoxidans infections in two Belgian reference centres (Antwerp and Ghent). Several of these patients also stayed at the Rehabilitation Centre De Haan (RHC). In total, 59 A. xylosoxidans isolates from 31 patients (including 26 CF patients), collected between 2001 and 2014, were studied. We evaluated Matrix Assisted Laser Desorption Ionisation -Time of Flight mass spectrometry (MALDI-TOF) as an alternative for McRAPD typing., Results: Both typing approaches established the presence of a major cluster, comprising isolates, all from 21 CF patients, including from two patients sampled when staying at the RHC a decade ago. This major cluster was the same as the cluster established already a decade ago at the RHC. A minor cluster consisted of 13 isolates from miscellaneous origin. A further seven isolates, including one from a non-CF patient who had stayed recently at the RHC, were singletons., Conclusions: Typing results of both methods were similar, indicating transmission of a single clone of A. xylosoxidans among several CF patients from at least two reference centres. Isolates of the same clone were already observed at the RHC, a decade ago. It is difficult to establish to what extent the RHC is the source of transmission, because the epidemic strain was already present when the first epidemiological study in the RHC was carried out. This study also documents the applicability of MALDI-TOF for typing of strains within the species A. xylosoxidans and the need to use the dynamic cutoff algorithm of the BioNumerics® software for correct clustering of the fingerprints.

Case description The use of i.v. colistin reappeared recently for the treatment of multidrug-resistant Gram negative organisms in the intensive care and cystic fibrosis (CF) setting. According to the latest pharmacokinetic data, a loading dose and high antibiotic doses are given. Two cases of adverse events (paraesthesias, bad taste) were observed immediately after the start of infusion of a high dose of i.v. colistin in adult CF patients at the Ghent University Hospital. Conclusion Recommendations for optimal administration of i.v. colistin in adult CF patients are scarce. This article highlights the importance of mode of administration to avoid toxicity and relates it to recent pharmacokinetic/-dynamic literature.

Background: Cystic Fibrosis (CF) patients are vulnerable to airway colonization with Pseudomonas aeruginosa. In case eradication fails after antibiotic treatment, patients become chronically colonized with P. aeruginosa, with recurrent pulmonary exacerbation, for which patients typically are hospitalized for 2 weeks and receive intravenous antibiotic treatment. Normally, improvement of the patients' health is established., Aim: Determination of the correspondence between patient improvement and changes of the P. aeruginosa and total bacterial load in the sputum., Methods: Eighteen CF patients with exacerbation were included for a total of 27 hospitalization episodes. At day 1, 8 and 15, inflammation and lung function parameters were determined, together with the P. aeruginosa load in the sputum using culture, quantitative PCR (qPCR) and propidium monoazide qPCR., Results: Patients improved during hospitalization (decrease in levels of C-reactive protein, white blood cell counts and erythrocyte sedimentation rate, increase of FEV1), reaching normal values already after one week. Also the P. aeruginosa load and the total bacterial load decreased during the first week of antibiotic treatment (p<0.05), except for patients with a low lung function (FEV1≤39.4%), for whom no significant decrease of P. aeruginosa was established. Comparison of culture-based and propidium monoazide qPCR-based quantification of P. aeruginosa showed that at the end of the treatment on average 62% of the P. aeruginosa cells are not cultivable, indicating that many cells are alive but dormant, or dead but still structurally intact., Conclusion: Improvement of the clinical status is accompanied with a decrease of the P. aeruginosa load, whereby both occur mainly during the first week of antibiotic treatment. However, for patients with a low lung function, no decrease of the P. aeruginosa load is observed. Comparison of detection techniques shows that a large amount of noncultivable or dead bacteria are present in the samples.

Objective: To investigate the occurrence of spirometry-related pain and distress in adolescents and young adults with cystic fibrosis (CF), and to investigate the role of acceptance of illness in spirometry-related pain and distress., Methods: A total of 36 adolescents and young adults with CF (12 to 22 years of age) completed a questionnaire assessing acceptance of illness. Spirometry-related distress was assessed using self-report (ie, anxiety⁄worry about the procedure) and physiological outcomes (ie, heart rate and heart rate variability) before spirometry. Spirometry-related pain was assessed using self-report (ie, expected pain and pain-related thoughts). Self-reported distress and pain during spirometry were also assessed., Results: Eighty-nine per cent of subjects reported distress before spirometry, 67% experienced distress during spirometry, 28% expected pain during spirometry and 22% actually experienced pain. Interestingly, partial correlations revealed that more acceptance was related to less expected pain and pain-related thoughts. Acceptance, however, was unrelated to distress, anxiety and pain during spirometry., Discussion: The present study suggests that a non-negligible number of adolescents and young adults with CF experience pain and distress during spirometry. Furthermore, results indicate that acceptance may play a protective role in the more indirect consequences of CF such as expected pain and pain-related thoughts during medical procedures. Acceptance, however, was not related to distress before and during spirometry, nor to experienced pain. These findings contribute to the increasing evidence that acceptance may play a protective role in managing the consequences of living with CF.

Aim: The aim of this study was to evaluate the effect of the surface functionalization of model nanoparticles on their mobility in bacterial biofilms and cystic fibrosis sputum., Materials & Methods: With single-particle tracking microscopy, the mobility of 0.1- and 0.2-µm fluorescent polyethylene glycol (PEG) modified, carboxylate- and N,N-dimethylethylenediamine-modified polystyrene nanospheres were evaluated in fresh cystic fibrosis sputum, as well as Burkholderia multivorans and Pseudomonas aeruginosa biofilms., Results: PEGylation increased the mobility of the particles in sputum and biofilms, while the charged nanospheres were strongly immobilized. However, the transport of the PEGylated nanoparticles was lower in sputum compared with biofilms. Furthermore, the particle transport showed heterogeneity in samples originating from different patients., Conclusion: This study's data suggest that for future nanocarrier design it will be essential to combine PEGylation with a targeting moiety to ensure sufficient mobility in mucus and a better accumulation of the nanoparticles in the biofilm.

Pseudomonas aeruginosa (Pa) is one of the most common and clinically important pathogens in patients with cystic fibrosis (CF). Chronic Pa colonization in CF patients is associated with increased morbidity and mortality. Pa strains causing early infection are usually antibiotic sensitive and have low bacterial density in the airways. As a result, the treatment strategy has shifted from suppressive therapy in patients chronically colonized by Pa to attempts at early eradication therapy as soon as Pa is detected. In the literature, different treatment regimens have been studied. However, the optimal treatment regimen and duration of treatment are not yet determined. In this article, an overview on the natural history of early Pa colonization and the history of eradication treatment is given. Moreover, the results of the different eradication treatment trials and directions for future research are discussed., (Copyright © 2012 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Purpose: Quantitative ultrasound bone sonometry (QUS) might be a promising screening method for cystic fibrosis (CF)-related bone disease, given its absence of radiation exposure, portability of the equipment and low cost.The value of axial transmission forearm QUS in detecting osteopenia in CF was therefore studied., Methods: We investigated the application of QUS in the evaluation of bone status in a group of 64 adolescents (>12 years) and young adults (<40 years) with CF in a comparison with a dual X-ray absorptiometry (DXA) of the whole body and peripheral quantitative computed tomography (pQCT) of the radius at 4% and 66% sites., Results: Mean (SD) Z-scores of speed of sound (SOS), whole body bone mineral content (BMC), radial trabecular bone mineral density (BMD), and radial cortical BMD were respectively -0.31 (0.78), -0.09 (1.28), 0.10 (1.16) and -0.62 (2.88). The pQCT determined bone geometry values (cortical bone area and cortical thickness) were more depressed than the BMD data. QUS had a sensitivity and specificity of respectively 0% and 96% for diagnosing osteopenia (based on a whole body BMC Z-score<-2)., Conclusions: QUS cannot replace DXA, but can screen out patients with normal bone mass. Further and larger studies are needed to examine if QUS may reflect other aspects than bone mass, or if it is possible to improve its sensitivity by supplementing the SOS results with clinical risk factors., (Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Previous studies proved the importance of rapid antibacterial intervention in case of Pseudomonas aeruginosa detection in respiratory samples of cystic fibrosis patients. To improve the early detection of P. aeruginosa, several culture, PCR and serology based approaches have been compared. Because an increasing number of routine microbiology laboratories have access to real-time PCR (qPCR), we reviewed the specificity and sensitivity of published PCR formats. The importance of choice of DNA-extraction methods and PCR formats and of the validation of their specificity and sensitivity with clinical samples is stressed., (Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Objective: To prospectively investigate the role of acceptance in well-being in adolescents and young adults with cystic fibrosis (CF)., Method: A total of 40 adolescents and young adults with CF (ages 14-22 years) completed questionnaires assessing acceptance, anxiety and depressive symptoms, physical functioning, role functioning, emotional functioning, and social functioning. After 6 months, 28 of them completed the questionnaires on anxiety and depressive symptoms, physical functioning, role functioning, emotional functioning, and social functioning a second time., Results: More acceptance (Time 1) was related to less depressive symptoms (Time 1 and 2), and to better role, emotional, and social functioning (Time 1)., Conclusions: Results indicate that accepting the limitations imposed by chronic disease and readjusting life goals may have a positive effect upon well-being in adolescents and young adults with CF. Further research is needed to clarify whether acceptance-based interventions are useful in promoting well-being in adolescents and young adults with CF.

Background: Pseudomonas aeruginosa is the major respiratory pathogen causing severe lung infections among CF patients, leading to high morbidity and mortality. Once infection is established, early antibiotic treatment is able to postpone the transition to chronic lung infection. In order to optimize the early detection, we compared the sensitivity of microbiological culture and quantitative PCR (qPCR) for the detection of P. aeruginosa in respiratory samples of not chronically infected CF patients., Results: In this national study, we followed CF patients during periods between 1 to 15 months. For a total of 852 samples, 729 (86%) remained P. aeruginosa negative by both culture and qPCR, whereas 89 samples (10%) were positive by both culture and qPCR.Twenty-six samples were negative by culture but positive by qPCR, and 10 samples were positive by culture but remained negative by qPCR. Five of the 26 patients with a culture negative, qPCR positive sample became later P. aeruginosa positive both by culture and qPCR., Conclusion: Based on the results of this study, it can be concluded that qPCR may have a predictive value for impending P. aeruginosa infection for only a limited number of patients.

Background: Longitudinal data regarding the genotypes of Pseudomonas aeruginosa isolates after eradication treatment are limited. We followed cystic fibrosis patients after a first ever isolation of P. aeruginosa and evaluated the P. aeruginosa-free time period after eradication therapy., Methods: Between January 2003 and December 2008 respiratory samples were cultured prospectively from 41 patients with a first ever P. aeruginosa isolate. Twenty five patients had at least one subsequent isolate. Treatment efficacy was assessed based on the time to a second isolation and on comparison of the RAPD genotypes of the P. aeruginosa isolates., Results: Eleven patients became chronically colonized during the study period. For ten of these the second isolate had the same genotype as the first isolate. Moreover, these patients had a significantly shorter P. aeruginosa-free time interval between the first ever and the second isolate compared to the 14 not chronically colonized patients (median 0 months versus 7.5 months, p<0.05)., Conclusion: Our results indicate that the presence of a genotypically identical subsequent P. aeruginosa isolate and/or a short P. aeruginosa-free time interval after treatment are ominous signs and might be useful additional tools to predict impending chronic colonization. Current routine bacteriological methods for the detection of P. aeruginosa may lack the sensitivity to discriminate between true eradication and low bacterial persistence., (Copyright (c) 2009 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Background: Pseudomonas aeruginosa is the major pathogen involved in the decline of lung function in cystic fibrosis (CF) patients. Early aggressive antibiotic therapy has been shown to be effective in preventing chronic colonization. Therefore, early detection is important and sensitive detection methods are warranted. In this study, we used a dilution series of P. aeruginosa positive sputa, diluted in a pool of P. aeruginosa negative sputa, all from CF patients--to mimick as closely as possible the sputa sent to routine laboratories--to compare the sensitivity of three culture techniques versus that of two conventional PCR formats and four real-time PCR formats, each targeting the P. aeruginosa oprL gene. In addition, we compared five DNA-extraction protocols., Results: In our hands, all three culture methods and the bioMérieux easyMAG Nuclisens protocol Generic 2.0.1, preceded by proteinase K pretreatment and followed by any of the 3 real-time PCR formats with probes were most sensitive and able to detect P. aeruginosa up to 50 cfu/ml, i.e. the theoretical minimum of one cell per PCR mixture, when taking into account the volumes used in this study of sample for DNA-extraction, of DNA-elution and of DNA-extract in the PCR mixture., Conclusion: In this study, no difference in sensitivity could be found for the detection of P. aeruginosa from sputum between microbiological culture and optimized DNA-extraction and real-time PCR. The results also indicate the importance of the optimization of the DNA-extraction protocol and the PCR format.

Background: Achromobacter xylosoxidans is increasingly cultured in sputum from cystic fibrosis (CF) patients; nevertheless, there are few published data on the clinical impact of this infection or chronic colonisation., Methods: Relying on DNA fingerprinting techniques we studied the prevalence of A. xylosoxidans in our CF population. In a retrospective case control study the clinical status of patients with at least 3 sputum cultures positive for A. xylosoxidans over at least 9 months, at the moment of the first positive culture and during the period of colonisation were compared to age (+/-1 year), gender and to Pseudomonas aeruginosa colonisation controlled CF patients who had never A. xylosoxidans positive sputum cultures., Results: The prevalence of patients with at least one positive A. xylosoxidans culture was 17.9%. 5.3% of the patients fulfilled the criteria of our definition of colonisation. Colonised patients had a median age of 20 years (range 11-27 years) and a mean colonisation period of 1.5 (+/-0.9) years. At the moment of the first positive culture we found significantly lower Bhalla scores on HRCT scans of the lungs (11+/-3 versus 16+/-3, p<0.002), lower Brasfield chest X-ray scores (14+/-3 versus 18+/-3, p<0.019), lower FVC values (70%+/-22 versus 94%+/-12, p<0.017) and lower FEV(1) values (55%+/-32 versus 78%+/-23, p=0.123), although the latter did not reach significance. There was no significant difference in body mass index (BMI) (18.7+/-3 kg/m2 versus 19.6+/-3 kg/m2, p=0.8). Over the study period A. xylosoxidans-colonised patients did have more need for intravenous antibiotic treatment courses (19 versus 5, p<0.001); nevertheless, there was no significant difference in lung function decline over the study period (FVC: -6.25+/-12.34% versus -5.62+/-8.30%, p 0.77, FEV1: -5.62+/-8.30% versus -1.87+/-11.58%, p<0.47)., Conclusions: The prevalence of A. xylosoxidans infection or colonisation is probably underestimated. Colonised patients are mostly older, with more pronounced lung damage and lower lung function values. Although there was more need for intravenous antibiotic treatment courses, no faster decline in lung function was observed in A. xylosoxidans positive patients.

Despite absence of clear proof of efficacy, the use of inhaled corticosteroids (ICS) is widespread in cystic fibrosis (CF) patients. Therefore, the effect of ICS on lung function and other clinical variables was studied in 27 prepubertal CF children with mild to moderate lung disease. In a prospective double-blind case-controlled study, fluticasone propionate 500 microg or placebo were administered twice daily during 12 months. The mean (standard error of the mean, SEM) patient age was 8.2 (0.6) years in the placebo group and 9.0 (0.5) years in the fluticasone group. The mean (SEM) forced expiratory volume in 1 s (FEV(1)) was 91% (4%) in the placebo group and 86% (4%) in the fluticasone group. There was no statistically significant difference in the evolution of lung function and the number of respiratory exacerbations between groups. However, longitudinal growth in fluticasone patients was significantly slower than in placebo patients: 3.96 (0.29) cm versus 5.49 (0.38) cm [p<0.005, analysis of variance (ANOVA)] over the 12-month study duration. This resulted in a significant change in height standard deviation score (SDS) of -0.38 (0.09) in the fluticasone group versus -0.01 (0.07) in the placebo group (p<0.003, ANOVA). No catch-up growth was noted 1-2 years after discontinuation of inhaled steroids. The use of high-dose ICS in CF patients with mild lung disease may lead to persistent growth impairment.

During a study examining transmission of Pseudomonas aeruginosa among 76 cystic fibrosis patients in a rehabilitation center, where patients stay in close contact during prolonged periods, several clusters of patients carrying genotypically identical P. aeruginosa, as well as two clusters of 4 and 10 patients, respectively, colonized with genotypically identical Achromobacter xylosoxidans strains, were discovered.

Objectives: Antibiotic therapy is of vital importance for the control of infectious exacerbations in cystic fibrosis (CF) patients. However, very little is known regarding the fraction of systemically administered antibiotics reaching the lower respiratory tract secretions. We developed and validated a method to measure the concentrations of piperacillin, ceftazidime, meropenem and aztreonam in CF sputum, and present the validation data.Methods: Ultra-performance LC coupled to tandem MS was used. A single sample can be measured in 2.5 min with multiple reaction monitoring in positive electrospray ionization mode. Deuterated internal standards were used and a concentration range of 0.7-160 mg/L was covered. The method was validated according to the EMA guideline on analytical method validation.Results: The boundaries within which a reliable measurement in CF sputum can be performed were determined. A few constraints are linked to the instability of the antibiotics in sputum. Piperacillin showed limited stability at room temperature and during freeze-thaw cycles. Autosampler instability was observed after 15 h for aztreonam at low concentrations.Conclusions: The method allows a reliable measurement of the selected antibiotics, if precautions are taken regarding the limited stability of piperacillin at room temperature. Due to freeze-thaw instability, piperacillin should always be analysed on the day of sampling. Quick review of the analytical data and reanalysis are needed as low concentrations of aztreonam are not stable in the autosampler. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to develop a novel strategy for the isolation and identification of Burkholderia cepacia complex bacteria from the home environment of cystic fibrosis (CF) patients. Water and soil samples were enriched in a broth containing 0.1% l-arabinose, 0.1% l-threonine, and a mixture of selective agents including 1μgml−1 C-390, 600Uml−1 polymyxin B sulfate, 10μgml−1 gentamycin, 2μgml−1 vancomycin and 10μgml−1 cycloheximide. On selective media (consisting of the same components as above plus 1.8% agar), several dilutions of the enrichment broth were inoculated and incubated for 5 days at 28°C. Isolates with different randomly amplified polymorphic DNA patterns were inoculated in Stewart’s medium. Putative B. cepacia complex bacteria were confirmed by means of recA PCR and further identified by HaeIII-recA restriction fragment length polymorphism analysis. Our results suggest that these organisms may be more widespread in the home environment than previously assumed and that plant associated soil and pond water may be reservoirs of B. cepacia complex infection in CF patients. [Copyright &y& Elsevier]