Ralstonia mannitolilytica is a Gram-negative soil bacterium. Pseudomonas thomasii and Ralstonia pickettii are synonyms. R. mannitolilytica has been implicated as an opportunistic pathogen in hospital-acquired infections, including a 1976 United Kingdom outbreak due to a contaminated distilled water supply, a 1989 outbreak in Taiwan caused by contaminated 0.9% sodium chloride solution, and a 2005 outbreak in children in the United States that was linked to contaminated Vapotherm respiratory gas humidification devices.