Molecular Characterization of Strains Isolated in Italy.

is the causative agent of several diseases and enteric infections in animals and humans. The pathogenicity of the bacterium is largely mediated by the production of a wide range of toxins. Individual strains produce only subsets of this toxin repertoire, which permits the classification in seven toxinotypes (A-G). In addition, a variety of minor toxins further characterizes the single strains. The aim of this work was to evaluate, using Polymerase Chain Reaction (PCR) assays, the diversity of 632 strains isolated in Italy over 15 years. The genotyped strains were analyzed to determine the presence of major and minor toxins (, and ), their geographical origins, and the source of isolation (animal species or food). Our study shows that toxinotype A had the greatest representation (93%) and correlated mainly with in a variety of animal species, as well as with in the five food samples. Type D, associated with and minor toxins, was identified in 3% of the cases, and type F was identified in 2.5%. Seven type C isolates (1.1%) were detected in cattle, whereas the only type B isolated in Italy was detected in a goat, and one type E was detected in a sheep. Type G was not detected.