Source attribution of foodborne ESBL-E.coli using data from the RESET consortium

Extended-spectrum beta-lactamases (ESBL) confer resistance against a wide spectrum of ß-lactam antibiotics, including penicillins, 2nd-, 3rd- and 4th-generation cephalosporins. In addition, such bacteria are often resistant to other antimicrobial classes. This can be challenging if human infections have to be treated. These days, there is an intensive discussion about the origin of SBLproducing E. coli in humans. Within the German RESET project several studies investigate the prevalence of ESBL-producing E. coli and characterise the isolates using phenotypic and genotypic techniques. Based on these results, we estimate the contribution of different animal sources (broiler, fattening pigs, and cattle) to human cases, using data from the ongoing studies. Our model is based on the well established Salmonella source attribution model using microbial subtyping data. Information on ESBL-genes, phylogenetic groups and prevalence rates is incorporated. First attempts using preliminary data sets indicate that many human cases can not be explained by the animal sources considered. The remaining cases are allocated equally to all sources considered and indicate the need of additional subtyping information. Therefore, we will present results for an up-to-date German data set including antimicrobial resistance patterns. This approach can help to assess the role of foodborne exposure.