DNA hybridization technique to detect Shigella species and enteroinvasive escherichia coli.

A DNA hybridization method for the detection of Shigella species and enteroinvasive Escherichia coli is described. It is based upon the high degree of homology shared by the virulence plasmids present in all pathogenic strains. After 32P labeling, a 17-kilobase EcoRI restriction fragment of a virulence plasmid belonging to Shigella flexneri serotype 5 was used as a probe to detect Shigella species and enteroinvasive E. coli in isolated colonies. This method proved highly specific as well as sensitive and should be particularly useful for the characterization of atypical isolates and for large-scale epidemiological studies in endemic areas.