Description:
<p>The objectives of this study were to characterize the antibacterial substances produced by Enterococcus faecium YT52<br />isolated from boza, and to evaluate the safety of this strain. E. faecium YT52 inhibits various Gram-positive bacteria,<br />including foodborne pathogens such as Listeria monocytogenes and Bacillus cereus. The manner of action of its<br />antibacterial activity, using proteolytic enzymes, indicate that it produces a bacteriocin. The bacteriocin producing isolate<br />E. faecium YT52 was identified using 16S rRNA gene homology and species-specific polymerase chain reaction (PCR)<br />analysis. The bacteriocin was found to be heat stable and active under both acid and alkaline conditions. The bacteriocin<br />showed primary metabolite kinetics and a bactericidal mode of action against L. monocytogenes. Although enterocin A, B<br />and X genes were detected in E. faecium YT52 by PCR, only one active peptide band (* 5.5 kDa) with a molecular<br />weight similar to enterocin B was identified by tricine–SDS-PAGE analysis. A safety evaluation of E. faecium YT52<br />indicated that it is nonhemolytic, gelatinase-negative, and susceptible to clinically relevant antibiotics such as ampicillin,<br />tetracycline and vancomycin. It contains a small number of virulence factors (efaAfm, silent gelE) and antibiotic resistance<br />genes (ermB, tetM, tetL). In conclusion, bacteriocinogenic E. faecium YT52 was found to have a low risk profile, and it<br />may be potentially valuable as a protective culture in the food industry.</p>