Prevalent STEC serotypes isolated from cattle, foods and environment in Argentina.

PADOLA, NORA L.; ETCHEVERRÍA, ANALÍA I.; LUCCHESI, PAULA M.A.; KRÜGER ALEJANDRA; SANZ, MARCELO, E; FERNÁNDEZ, DANIEL; ALONSO, MÓNICA Z.; POLIFRONI, ROSANA; ARROYO, GUILLERMO H.; PARMA, ALBERTO E.

Amsterdam

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

Asociación Argentina de Micerobiología

STEC is the main aetiological agent of haemolytic uraemic syndrome (HUS) and cattle are the main reservoir of STEC that is transmitted to humans through contaminated foods, water, direct contact with animals and the environment. Although the serotype more frequently implicated in HUS is O157:H7, there are several other serotypes associated with human infections: O26:H11/H-, O91:H21/H-, O103:H2, O111:H-, O113:H21, O118:H16, O121:H19, O128:H2/H-, O130:H11, O141:H19, O145:H28/H-, O146:H21, O163:H19, O172:H-, and O178:H19. Argentina has the highest incidence of HUS (17/100,000 children under five years old), and several serotypes have been isolated from human cases in this country: O157:H7, O145:H-, O178:H19, O91:H21 and serogroups as O26, O174, and O111. The aim of this work was to determine the serotypes shared among cattle, foods and environment and assess which are the most prevalent in a collection of STEC isolated in Argentina. The isolates came from 4824 samples from cattle, foods (hamburger and minced meat) and environment of farms. From those, 545 were characterized by multiplex PCR to detect stx1, stx2, eae, ehxA and saa and then were serotyped. The prevalent serotypes were O8:H19; O26:H11; O91:H21; O113:H21; O117:H7; O130:H11; O145:H-; O157:H7; O171:H2 and O178:H19, corresponding to 61 % of typable strains. There were serotypes shared between cattle and foods, between cattle and the environment and among cattle, foods and environment. Ninety eight seroytpes (18%) were non-typable (Table 1).   Serotype Percentage of strains (%)       Virulence profiles (n=447) Cattle Foods Environment O178:H19 13 95 5 0 stx2 stx2 saa ehxA stx1 stx2 saa ehxA O130:H11 9 93 7 0 stx1 stx2 saa ehxA stx1 saa ehxA O113:H21 8 86 14 0 stx2 saa ehxA stx1 stx2 saa ehxA stx1 eae ehxA stx2 O26:H11 5 91 0 9 stx1 eae ehxA stx2 eae ehxA O91:H21 5 95 5 0 stx2 saa ehxA O171:H2 5 86 14 0 stx2 O117:H7 3 50 50 0 stx2 O145:H- 3 93 0 7 stx1 eae ehxA stx2 eae ehxA stx1 eae stx2 eae O157:H7 3 93 7 0 stx2 eae ehxA O8:H19 2 45 45 10 stx1 stx2 ehxA stx1 ehxA stx2 The most prevalent serotypes from cattle, foods and environment in Argentina have been also isolated from human cases in several countries including Argentina, and their virulence profiles reflect the pathogenic potential of the strains.