Clonal Relationships among Enterococcus faecalis from Humans and Animal-Origin Foods in Xinjiang Characterized by Multilocus Sequence Typing

In this study, the population structure and evolutionary relationships of 59 Enterococcus faecalis strains isolated from breast milk, cheese, camel milk, mare milk and cold water fish from Xinjiang were analyzed by multilocus sequence typing (MLST). All the isolates were allocated into 12 sequence types, including three clonal complexes and three singletons. None of the sequence types were found to belong to high risk clonal complexes. Housekeeping gene split decomposition analysis indicated that gene recombination could be a major driving force in the evolution of E. faecalis. The results of minimum spanning tree indicated these E. faecalis strains were relatively weakly related to their geographical origin. Although eBURST and phylogenetic analysis demonstrated that the isolates from breast milk and cold water fish exhibited host specificity, E. faecalis clones closely related to them were still detected in breast milk, cheese, mare milk and camel milk. Taken together, E. faecalis from different hosts can adapt to new niches and spread via production practice and the food chain. Continuous monitoring is necessary to reduce the potential risk of zoonotic diseases