JMM Profile: Achromobacter xylosoxidans: the cloak-and-dagger opportunist.

Achromobacter xylosoxidans is associated with resilient nosocomial infections, with bacteraemia, pneumonia and chronic cystic fibrosis lung infection being the most common clinical presentations. Innate multi-drug resistance and a suite of virulence factors select for A. xylosoxidans infection during long-term antibiotic therapy, contributing to its persistence, treatment recalcitrance, association with poor clinical outcomes and emergence as a problematic pathogen. Horizontal gene transfer and maintenance of large genomes underpin the resilience and cosmopolitan lifestyle of A. xylosoxidans, and complicate its phylogenetic characterization.