Characterization of functional properties of Enteroccoccus feacium strains isolated from human gut

The aim of this work was to characterize the functional properties of Enterococcus faecium strains identified after isolation from human faeces. Of these isolates strain R13 showed the best resistance to low pH, bile salts and survival in the simulated in vitro digestion assay and demonstrated an important level of adhesion to hexadecane as a potential probiotic candidate. Analysis of the antibiotic resistance of E. faecium strains indicated that in general these isolates were sensitive to the tested antibiotics and no strain appeared to be resistant to vancomycin. Examination of the virulence determinants for E. faecium strains demonstrated that all strains contained the virulence genes common in gut and food originated enterococci and strain R13 harboured the lowest number of virulence genes. Additionally no strain contained the genes related with the cytolysin metabolism and showed hemolytic activity. The antimicrobial role of E. faecium strains were tested against several pathogens in which different levels of inhibitory effects were observed and strain R13 was inhibitory to all tested pathogens. The PCR screening of genes encoding enterocin A and B indicated the presence of these genes in E. faecium strains. Preliminary characterization of bacteriocins revealed that their activity was lost after proteolytic enzyme treatments but no alteration in antimicrobial activity was observed at different pHs (3.5 to 9.5) and after heat treatments. In conclusion this study revealed the functional characteristics of E. faecium R13 as a gut isolate and this strain could be developed as a new probiotic after further tests.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author