title: Genetic relationships among Enterococcus faecalis isolates from different sources as revealed by multilocus sequence typing.
abstract: Enterococcus faecalis is part of the natural gut flora of humans and other mammals; some isolates are also used in food production. So, it is important to evaluate the genetic diversity and phylogenetic relationships among E. faecalis isolates from different sources. Multilocus sequence typing protocol was used to compare 39 E. faecalis isolates from Chinese traditional food products (including dairy products, acidic gruel) and 4 published E. faecalis isolates from other sources including human-derived isolates employing 5 housekeeping genes (groEL, clpX, recA, rpoB, and pepC). A total of 23 unique sequence types were identified, which were grouped into 5 clonal complexes and 10 singletons. The value of standardized index of association of the alleles (IA(S)=0.1465) and network structure indicated a high frequency of intraspecies recombination across these isolates. Enterococcus faecalis lineages also exhibited clearly source-clustered distributions. The isolates from dairy source were clustered together. However, the relationship between isolates from acidic gruel and one isolate from a human source was close. The MLST scheme presented in this study provides a sharable and continuously growing sequence database enabling global comparison of strains from different sources, and will further advance our understanding of the microbial ecology of this important species.
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Song
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
authors.forename: H Y
authors.initials: HY
authors.lastname: Xu
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
authors.forename: B L G
authors.initials: BL
authors.lastname: Menghe
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China.
authors.forename: H P
authors.initials: HP
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Inner Mongolia Agricultural University, Hohhot, 010018, P. R. China. Electronic address: sunzhihong78@163.com.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Sun
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D003611:Dairy Products / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D005516:Food Microbiology; D014644:Genetic Variation; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins
keywords: Enterococcus faecalis; genetic relationship; multilocus sequence typing