L. Van Simaey

75 A single clone of Achromobacter xylosoxidans colonizes Belgian cystic fibrosis patients from different centres

Objective Several major infection problems with Achromobacter xylosoxidans were observed for CF patients in Belgium. We tried to assess the epidemiology. Methods We typed 50 strains from 24 CF patients – from Ghent University Hospital (UZG, n=17) and from the University of Antwerp Hospital (UZA, n=7), most of which (14 from Ghent and 5 from Antwerp) had stayed at the rehabilitation centre. CF-related strains had been collected over a period of 10 years. We also included 8 unrelated strains: 7 clinical strains from non-CF patients and the type strain. McRAPD (arbitrarily primed PCR in combination with melting curve analysis)(Deschaght et al. 2011. Res Microbiol 162: 386–392), nrdA gene sequencing (Spilker et al. 2013. J Cystic Fibrosis 12: 298–301) and MALDI-TOF typing (newly developed) were used for typing. Results Typing revealed that most isolates from CF patients were indistinguishable by any of the three approaches. Only 6 CF patients had invididual types of A. xylosoxidans . Non-CF strains, including the one isolated from a non-CF patient at the rehabilitation centre, belonged to separate genotypes. The major clone observed in this study had previously been recognized as a major cluster (10 patients) in the rehabilitation centre of De Haan and its distinctness from a previously established minor cluster in De Haan (4 patients, Van Daele et al. 2005. J Clin Microbiol 43: 2998–3002) was confirmed in this study. Conclusion These data indicate that most CF patients from different CF centres in Belgium are colonized by a single clone of genuine A. xylosoxidans , that is spreading since at least 10 years. We thank the MucoVereniging Belgium

WS19.7 Pseudomonas aeruginosa genotyping: Predicting transition to chronic colonization in cystic fibrosis patients

Objectives Chronic respiratory infection with Pseudomonas aeruginosa (Pa) is known to increase morbidity in cystic fibrosis (CF) patients. Following a first ever Pa isolation, patients may go through subsequent episodes of intermittent colonization, preceding chronic colonization by a variable time span, before chronic infection eventually is established. Currently, definitions of chronic colonization are based on the frequency of Pa isolation. This study evaluates whether genotyping of subsequent Pa isolates can be predictive towards persistence of Pa , and therefore towards transition from intermittent to chronic colonization. Methods Between January 2002 and December 2014 respiratory samples were prospectively collected and cultured from 80 CF patients with a first ever Pa isolation and all available isolates were compared using McRAPD genotyping (Deschaght et al.). Results Sixty-eight patients, 22 of which became chronically colonized – according to the European consensus criteria – during the study period, had at least one subsequent Pa isolate. Isolates were genotyped for a sample group of 25 patients. For 10 out of the 11 patients becoming chronically colonized during the study period. the first and second isolate were identical, as compared to for only 7 out of the 14 patients remaining non-chronically colonized (p Conclusion Our results indicate that the presence of a genotypically identical subsequent Pa isolate can predict impending chronic colonization. As such, genotyping and comparison of the subsequent Pa isolates could – for many patients – speed up the diagnosis of chronic colonization, compared to the currently used criteria.

58 Achromobacter xylosoxidans/ruhlandii colonized CF patients have more hospitalisations and IV antibiotic days

Objective Achromobacter xylosoxidans (Ax) colonisation is an increasing problem in the CF population. Previous cross-sectional research could not elucidate whether bronchial deformations are caused by Ax colonisation or whether Ax colonisation is a consequence of bronchial damage. Methods We performed a case control study (10/10) and compared Ax colonised patients with controls matched for gender, age and P. aeruginosa colonisation. Ax patients were selected when becoming chronically colonised, according to the Leeds criteria for chronic P. aeruginosa colonisation. Lung function (FEV1, FEF25–75), number of hospitalisations, IV antibiotic days and BMI were calculated over a period from the first positive sputum culture until January 2015. Results No differences were found in lung function parameters, although there was a tendency for a lower FEF25–75 (p = 0.09) in Ax colonized patients. No difference in BMI was recorded. In Ax colonised patients, significant more hospitalisations (p Conclusion CF patients chronically colonized by Ax require more hospitalization periods and IV antibiotic days. These findings suggest increased bronchial damage leading to higher number of infectious exacerbations in Ax colonized patients. Although no differences in lung function decline were observed, there was a tendency of a steeper decline in FEF25–75, suggesting increased small airway inflammation related to Ax colonization.

159 Genotyping of Achromobacter xylosoxidans in a cystic fibrosis (CF) centre

Background and Objectives: Fungi, particularly Aspergillus and Candida species, are increasingly found in cystic fibrosis (CF) airway fluids. However, their association with other CF pathogens, medications and lung function, especially in CF children, remains elusive. We analyzed the relationship of fungal colonization to microbiological and clinical parameters of pediatric CF patients. Methods and Results: Fungal colonization and long-term clinical parameters like BMI and lung function were retrospectively studied in over 500 CF patients. Colonization was defined based on Chotirmall et al. (Chest 2010). Candida albicans (CA) was the most prevalent fungus detected in CF airway fluids, followed by C. non-albicans > Aspergillus fumigatus (AF) > A. non-fumigatus species. We found an association between fungal colonization and (among other parameters) bacterial co-colonization, lung function, BMI and antibiotic therapy. Conclusion: This study suggests that colonization with CA or AF is affected by bacterial co-colonization and may modulate the disease severity already in pediatric CF patients.