Investigation of hospital-acquired infections due to Alcaligenes denitrificans subsp. xylosoxydans by DNA restriction fragment length polymorphism.

We demonstrate that DNA restriction fragment length polymorphism determined by pulsed-field gel electrophoresis is very useful in the investigation of the epidemiology of hospital-acquired infections caused by Alcaligenes denitrificans subsp. xylosoxydans. This approach showed that hospital-acquired infections caused by this opportunistic pathogen over a 6-month period in 10 patients hospitalized in an intensive care unit and a surgical unit were not a true outbreak. In addition, this molecular typing method established that the respiratory therapy equipment was the source of the contamination of two patients.