Verotoxin variants in VTEC isolated from children with acute diarrhoea from Central-Eastern Argentina. Association with clinical symptoms, seasonality and hamburger consumption.

MARIANA ALEJANDRA RIVERO; ALEJANDRA KRUGER; PAULA MARÍA LUCCHESI; ALBERTO ERNESTO PARMA

Amsterdam

Simposio; 8th International Symposium on Shiga Toxin (Verocytotoxin) Producing Escherichia coli Infections.; 2012

VTEC 2012 congress organizers

In this study, the vt genes variants present in 32 verotoxin-producing Escherichia coli (VTEC) strains were investigated. These strains were isolated from 437 children up to 6 years old with acute diarrhoea attended at Hospitals from Tandil and Bahía Blanca cities, 8% of whom progressed to Haemolytic Uraemic Syndrome (HUS). The associations among vt variants combinations and clinical symptoms, age, season, region, and hamburger consumption were also assessed. The vt genes variants were identified by PCR-RFLP. An ordinal linear model for multinomial data was used considering as response variable the vt variants profile (in the order: vt2EDL933+vt2vha; vt2EDL933; vt1EDL933), with cumulative logit as link function. Sixteen of the 32 isolates (50%) carried vt2EDL933+vt2vha genes and belonged to the O157:H7 serotype, usually associated with severe disease. Thirteen strains (40.6%) carried vt2EDL933, and belonged to O145:H- (7), O157:H7 (3), O121:H19 (2) and O26:H11 (1). Three strains (9.4%) carried vt1 alone and belonged to the serotypes O111:H8 (1), O26:H11 (1) and O118:H2 (1), generally related with milder symptoms. Considering the order of the combination of the vt variants (vt2EDL933+vt2vha; vt2EDL933; and vt1EDL933) a significant difference and an association was found in the distribution frequency of the variants combinations with HUS development (OR 6.04; CI95% 1.58-23.12; p=0.0051); bloody diarrhoea (OR 2.97; CI95% 1.23-7.80; p=0.0252); warm season (OR 3.21; CI95% 1.03-10.07; p=0.0418) and Bahía Blanca city (OR 11.94; CI95%:4.38-32.55; p