【摘 要】
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Enterococcus faecalis is one of the most important species inthe genus Enterococcus.Although some isolates are considered as human pathogens,other isolates are used in food production.It is therefore
【机 构】
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Key Laboratory of Dairy Biotechnology and Engineering,Education Ministry ofP.R.China,Inner Mongolia
【出 处】
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第七届全国微生物资源学术暨国际微生物系统与分类学研讨会
论文部分内容阅读
Enterococcus faecalis is one of the most important species inthe genus Enterococcus.Although some isolates are considered as human pathogens,other isolates are used in food production.It is therefore important to understand the genetic diversity and phylogenetic relationships between E.faecalis isolates from different sources.Multilocus Sequence Typing protocol(MLST)was used to compare 39 E.faecalisisolates from Chinese traditional food products(including dairy products,acidic gruel)and 4 published E.faecalisisolates from other sources including human-derived isolates.Sequences from five selected housekeeping genes(groEL,clpX,recA,rpoB and pepC)were compared and 23 unique sequence types(STs)were obtained by sequencing analysis.The value of standardized index of association of the alleles(IAs =0.1465)and network structure revealed by split-decomposition analysis indicated a high frequency of intraspecies recombination across the population of E.faecalis isolates.Phylogenetic analysis based on the sequences of the five selected MLST loci showed that the isolates belonged to five clonal complexes(CCs)and there were ten singletons.It also indicated that E.faecalis lineages exhibited clearly source-clustered distributions.Moreover,the relationship between isolates from acidic gruel and one isolate from a human-source was close.The results indicated that MLST is a valuable tool for typing E.faecalis isolates from different sources and can be used for further monitoring of evolutionary changes and population genetics.Moreover,it also suggests that more rigorous safety evaluation might be necessary when considering isolates from acidic gruel for further industrial application in food production.
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