Use of random amplified polymorphic DNA for epidemiological typing of Stenotrophomonas maltophilia

We used the technique of random amplification of polymorphic DNA (RAPD) to type 130 isolates of Stenotrophomonas (Xanthomonas) maltophilia, using four arbitrary short primers. Of the 130 isolates, 51 were from the hospital environment, 48 from clinical specimens and 31 were geographically diverse environmental isolates. DNA amplification with the four sets of primers generated 112 RAPD patterns that differed by two or more bands in one of the four primers. Sixteen pairs of isolates were of the same RAPD pattern and some of these pairs represented clinical strains obtained from patients hospitalized at the same time in the same ward. In three patients, two to three strains of S. maltophilia which gave different RAPD fingerprints were isolated on the same day from different specimens. RAPD fingerprinting demonstrated great genomic diversity within the species S. maltophilia and provided an effective method for the study of the epidemiology of both clinical and environmental strains.