[Serotype characterization of Escherichia coli potentially producing enterotoxins in foods]

The incidence of serotypes of Escherichia coli usually described as enterotoxins producer was investigated in 137 samples of food from different origins (animal and vegetal). The serological analysis of the somatic "O", capsular "K" and flagellar "H" antigens in 265 isolates of Escherichia coli resulted in the characterization of 34 strains, distributed in 12 serotypes. These organisms were obtained from 24 samples of food of animal origin. A possible association with epidemiological markers for other test, were analyzed. The fermentation pattern of the 34 strains with melibiose, raffinose, sucrose, salicin, and sorbitol allowed classification into 11 biotypes. However the marked heterogenicity of the biotypes distributed among the serotypes did not allow correlation between the serofermentative types and the origin of the food. The other tests based on hemolysis and hemagglutinating ability did not aid in the differentiation of the phenotypes.