Detection of Achromobacter xylosoxidans in Hospital, Domestic, and Outdoor Environmental Samples and Comparison with Human Clinical Isolates

Abstract

ABSTRACTAchromobacter xylosoxidansis an aerobic nonfermentative Gram-negative rod considered an important emerging pathogen among cystic fibrosis (CF) patients worldwide and among immunocompromised patients. This increased prevalence remains unexplained, and to date no environmental reservoir has been identified. The aim of this study was to identify potential reservoirs ofA. xylosoxidansin hospital, domestic, and outdoor environments and to compare the isolates with clinical ones. From 2011 to 2012, 339 samples were collected in Dijon's university hospital, in healthy volunteers' homes in the Dijon area, and in the outdoor environment in Burgundy (soil, water, mud, and plants). We designed a protocol to detectA. xylosoxidansin environmental samples based on a selective medium: MCXVAA (MacConkey agar supplemented with xylose, vancomycin, aztreonam, and amphotericin B). Susceptibility testing, genotypic analysis by pulsed-field gel electrophoresis, andblaOXA-114sequencing were performed on the isolates. A total of 50 strains ofA. xylosoxidanswere detected in hospital (33 isolates), domestic (9 isolates), and outdoor (8 isolates) samples, mainly in hand washing sinks, showers, and water. Most of them were resistant to ciprofloxacin (49 strains). Genotypic analysis andblaOXA-114sequencing revealed a wide diversity among the isolates, with 35 pulsotypes and 18 variants of oxacillinases. Interestingly, 10 isolates from hospital environment were clonally related to clinical isolates previously recovered from hospitalized patients, and one domestic isolate was identical to one recovered from a CF patient. These results indicate thatA. xylosoxidansis commonly distributed in various environments and therefore that CF patients or immunocompromised patients are surrounded by these reservoirs.