Molecular characterization of Diarrheagenic Escherichia coli in meat products

ObjectiveThis study aimed to understand the epidemic characteristics of Diarrheagenic Escherichia coli （DEC） in domestic meat products.MethodsThe molecular characteristics of 86 strains of DEC were analyzed by whole genome sequencing technology， and the dominant pathological types， STs， and serotypes were identified. The phylogenetic relationship between DEC strains derived from meat products in China was determined through whole genome single nucleotide polymorphism.ResultsThe results showed that the pathological types of DEC in meat products were mainly EAEC. Eighty-six DEC strains were divided into eight virulence genotypes， including 48 ST types （including six new ST types）， and 55 O：H serotypes. ST11 and CC10 were the predominant ST and clonal complex， respectively. O157， O15， and O6 were the predominant serogroups. DEC strains exhibited high genetic heterogeneity， the same pathological type had low homology， and they were in different evolutionary branches.ConclusionThere is no correspondence between DEC pathological types and ST types and serotypes. The pathological types cannot be directly judged by monitoring ST types and serotypes， but the most numerous ST types and serotypes reveal the main hazard characteristics and prevention of DEC. The determination method of DEC can be supplemented and optimized according to the results of whole genome sequencing， which can provide data support for the traceability and epidemiological investigation of DEC in the future.