Distribution of the species of Achromobacter in a French Cystic Fibrosis Centre and multilocus sequence typing analysis reveal the predominance of A. xylosoxidans and clonal relationships between some clinical and environmental isolates

BackgroundAchromobacter spp. are emerging pathogens in Cystic Fibrosis (CF) patients. Recent studies proposed Multilocus Sequence Typing (MLST) scheme and a species-level identification method by nrdA sequencing for this genus. Epidemiological data are needed to assess the species and/or the sequence types (STs) involved and their potential role in CF patients lung function degradation. The aims of this study were i) to describe the distribution of the different species of Achromobacter in our CF centre ii) to detect potential STs more involved in chronic colonisations iii) to detect a potential local or worldwide predominance of some STs among clinical and environmental isolates.MethodsAll the isolates (477) collected in our CF centre from 2007 to 2014 among the 177 patients attending the centre were identified using nrdA sequencing. MLST analysis was performed for 37 clinical and 14 environmental isolates.ResultsA total of 47 out of 177 patients presented positive culture(s) with Achromobacter spp., representing 12.7% of the patients of the centre each year. Eleven species were detected, A. xylosoxidans being the most prevalent species (27 patients). Only A. xylosoxidans (> 80%) and A. insuavis were involved in chronic colonisation (6.7%). MLST analysis revealed a wide diversity among the isolates (36 STs for 51 isolates). Nevertheless, one third of the isolates belonged to STs previously detected in clinical isolates from other countries.ConclusionsThis study is a first approach in understanding the global epidemiology of Achromobacter species in CF. These results confirm the high prevalence of the species A. xylosoxidans among CF patients, reveal the worldwide distribution of some STs and point out the potential role of environmental sources of contamination. More studies are needed to search for relationships between species and/or ST and pathogenicity.