Diversity of nosocomial Xanthomonas maltophilia (Stenotrophomonas maltophilia) as determined by ribotyping.

Seventy-seven clinical isolates of Xanthomonas maltophilia (Stenotrophomonas maltophilia) were consecutively collected from the Rigshospitalet, Copenhagen, ribotyped and compared with the ribotypes of 25 other clinical and reference strains of Xanthomonas maltophilia. Using restriction enzyme EcoRI, 20 different ribotypes were observed, with 78 isolates displaying the five most common types. Using another enzyme, BamHI, these 78 isolates were further subdivided into 16 different ribotypes. Three patients harboured two strains with different ribotypes. No type was found related to only one department and no single-strain outbreak was detected. The origin of this wealth of different strains in hospital patients needs to be established.