Shiga toxin-producing Escherichia coli in meat and vegetable products in Emilia Romagna Region, years 2012-2013

Abstract

In 2012-2013 Emilia-Romagna Region introduced a monitoring plan for Shiga toxin-producing <em>Escherichia coli</em> (STEC) in foodstuff. Six hundred eighty-nine meat samples and 273 fruit and vegetable products were analyzed according to ISOTS13136. Pre-enriched samples were tested by multiplex real time PCR targeting the virulence genes <em>eae</em>, <em>stx1</em> and <em>stx2</em>. <em>Stx2</em> positive samples were investigated for the presence of serogroup O104 associated gene. O103, O111, O145, O157, O26 associated genes were tested on samples positive for <em>stx</em> in association with <em>eae</em> gene. Isolation of E. coli strains was attempted from samples positive for serogroup-associated genes. Thirtyfour meat products (4.9%) resulted positive for <em>stx1</em> and/or <em>stx2</em> genes and 46 (6.7%) for <em>stx1</em> and/or <em>stx2</em> genes in association with <em>eae</em> gene. Forty-five (6.5%) samples resulted positive at least at one serogroup. Serogroup O103, O104, O111, O145, O157 and O26 genes were detected respectively in 1.3, 0.3, 0.1, 3.9, 2.9 and 2.5% samples; 0.6% samples resulted positive for STEC isolation (2 <em>E. coli</em> O103 and 2 <em>E. coli</em> O157). It is worth noting that STEC virulence genes were detected at high frequency (19%) in fresh pork meat sausages. Four (1.5%) vegetable samples were positive for <em>stx1</em> and/or <em>stx2</em> genes and 1 (0.4%) for <em>stx1</em> and/or <em>stx2</em> genes in association with <em>eae</em> gene; none resulted positive for the tested serogroups. Only a low number of samples positive by molecular methods were confirmed by cultural isolation. It is therefore of the uttermost importance for appropriate risk management, to be fully aware of the meaning of the analytical result.