Characterization of typical and atypical enteropathogenic Escherichia coli (EPEC) strains of the classical O55 serogroup by RAPD analysis

the genetic diversity of 41 typical and atypical enteropathogenic escherichia coli (epec) strains of the serogroup o55 was analyzed by using the random amplified polymorphic dna (rapd) method. all typical epec o55 strains were grouped in two clusters (a and c) and belonged to the serotype o55:h6, while cluster b included all atypical strains, which were of the serotype o55:h7. the three groups also included non-motile strains. rapd may be a useful method for epidemiological studies on e. coli o55 infection.