Cloned, random chromosomal sequences as probes to identify Salmonella species.

We have developed and evaluated a new technique--chromosomal probe fingerprinting--to differentiate between strains of Salmonella species by using sequences of cloned chromosomal DNA as probes to highlight restriction site heterogeneity. Chromosomal probe fingerprint patterns were compared with other strain-typing methods and epidemiological data. Seventeen isolates of Salmonella typhimurium recovered from 11 outbreaks had six unique chromosomal probe fingerprint patterns. Most strains of Salmonella dublin, including some that had identical plasmid profiles and restriction endonuclease analysis patterns, could be distinguished by this method. On the other hand, eight of nine isolates of Salmonella enteritidis had a common chromosomal probe fingerprint pattern, although there were differences in plasmid profiles and the isolates had been collected over a lengthy time interval from widely disparate geographic locations. These results suggest clonal dissemination of some Salmonella serovars.