B-206. Correlation between the Presence of pet, pic and sat Genes and their Expression in Enteroaggregative Escherichia coli Strains Isolated from Children with and without Diarrhea

U. Hernandez, Sr.1, J. Lama-Plata1, M. Solano1, A. Navarro1, T. Sainz2, C. González2, C. Eslava1;
1Univ. Nacional Autonoma de Mexico, Mexico, MEXICO, 2Univ. Autonoma Metropolitana, Mexico, MEXICO.

The Serine Proteases AutoTransported of Enterobacteriaces (SPATEs) includes different toxins. Pet, Pic and Sat are toxins secreted by enteroagregative (EAEC) and uropathogenic (UPEC) E. coli respectively. A high homology in the aminoacids sequence, common epitopes and biological properties have been identified in both Pet and Sat toxins. In this study we are analyzing the correlation between the presence of genes and the expression frequency of Pet. Pic and Sat from EAEC strains isolated from children with and without diarrhea. A total of 286 EAEC strains isolated from children with (243) and without diarrhea (43) were analyzed by PCR (with specific primers) and western blot assays (with polyclonal antibodies). The statistical analysis was performed by X2 test with Fischer correlation (P> 0.005). The PCR results showed frequencies of 35%, 8% and 20% to Pic, Pet and Sat genes respectively. The western blot analysis showed that 41% of the supernatants obtained from EAEC strains reacted with anti Pic and 28% with anti Pet antibodies. Some strains amplified with both Pet and Pic or Pic and Sat primers, similar results were obtained in the western blot assay. The obtained results showed that Pic and Sat are SPATEs frequently secreted by EAEC strains isolated of children with diarrhea, and Pet the first SPATE identified in these strains is a virulence factor less common. This last could be associated with the plasmid localization of Pet gene. Studies with UPEC strains are in process to determine the frequency of the Pic, Pet and Sat genes.