USE OF RANDOM FRAGMENTS OF CHROMOSOMAL DNA TO HIGHLIGHT RESTRICTION SITE HETEROGENEITY FOR FINGERPRINTING ISOLATES OF SALMONELLA-TYPHIMURIUM FROM HOSPITALIZED ANIMALS

Random fragments of DNA were obtained from a cosmid library of Salmone lla agona genoMiC DNA. From this library, 2 fragments were chosen and pooled to probe isolates of S typhimurium obtained during an episode o f salmonellosis in a veterinary medical teaching hospital. Chromosomal DNA from the Salmonella isolates was digested with restriction endonu cleases, and was probed with the random fragments of chromosomal DNA. This procedure resulted in a fingerprint pattern for each isolate. We found that the method permitted discrimination between isolates involv ed in the disease episode and S typhimurium obtained prior to the epis ode. We conclude that random fragments of chromosomal DNA are useful f or fingerprinting isolates of S typhimurium. Analysis of plasmid DNA o btained from the isolates was not as useful. Some isolates found to be identical by restriction site analysis, had plasmids of different mol ecular weight. These results indicate that plasmid analysis may not be as useful a fingerprinting tool as previously reported.