Achromobacter xylosoxidans in hospital environments: still waters run deep!

BACKGROUND: Hospital reservoirs of Achromobacter xylosoxidans, responsible for nosocomial infections, are poorly known. METHODS: We examined the growth, survival and biofilm formation of five A. xylosoxidans strains for up to 2 y in distilled, dialysis or microfiltered water. Each strain was inoculated at 102 CFU/ml without adding nutrients. RESULTS: All strains grew at a level of 3x103 to 1.5x107 CFU/ml; each strain showed a preferred water type. Strains isolated from quaternary ammoniums showed the highest ability to grow and form biofilms in nutrient-poor waters. CONCLUSION: Medical waters and notably sterile distilled water bottles appear to be long-lasting reservoirs of A. xylosoxidans.