Laboratory detection of verocytotoxin-producing Escherichia coli in the official food control in Slovakia

The National Reference Centre (NRC) of Environmental Microbiology, Bratislava, Slovakia has been involved in the European Network of National Reference Laboratories for the official food control on Escherichia coli and Vero(Shiga) toxin-producing Escherichia coli (VTEC) under the authority of the European Community Reference Laboratory (EU-RL) in Rome since year 2006. In relation to the outbreak of hemorrhagic colitis in Germany in 2011, which was caused by Escherichia coli of serotype O104:H4, EU-RL regularly provided the laboratories in its network an up-to-date information concerning analytical procedures and organized the development of a protocol for the detection of VTEC. NRC analysed, during that period, approximately 45 samples of suspected bacterial strains of Escherichia coli isolated from food samples and biological materials. The strains were analysed for the presence of wx/ and vtx2 genes encoding verocytotoxins, and eae gene encoding the protein intimin. Using conventional and qualitative real-time polymerase chain reaction, isolates from food samples were found to be serogroups O128 and O146, and isolates from biological materials were found to be serogroups O26 and O119. The presence of genes encoding verocytotoxins was not detected, only the presence of eae gene. None of E. coli isolates was O104:H4.