# Do We Need to Worry About Staphylococcus epidermidis ST0409KOC, a Cheese‐Isolated Strain With Bacteriocinogenic Properties?

## TL;DR

A cheese-isolated Staphylococcus epidermidis strain shows low virulence and strong antibacterial activity, making it a potential probiotic candidate.

## Contribution

Characterization of a cheese-isolated S. epidermidis strain with low virulence and high bacteriocin activity against pathogens.

## Key findings

- S. epidermidis ST0409KOC has only one virulence gene (IS257) among 18 tested.
- The strain shows strong bacteriocin activity against Listeria monocytogenes and other pathogens.
- The strain is considered safe and a potential probiotic candidate.

## Abstract

Staphylococcus epidermidis is widely found throughout the entire length of human skin and animals since the first year of life, providing a natural protective barrier against other pathogenic microorganisms. Therefore, related to its reputation, it is of utmost importance to investigate the virulence capacity for strains of this species. The aim of this study was to evaluate the safety of S. epidermidis ST0409KOC, a strain isolated from Bulgarian feta‐type cheese, and to explore its bacteriocinogenic property against different strains of Listeria monocytogenes and other pathogens. S. epidermidis ST0409KOC can be considered a safe strain regarding its virulence genetic background, presenting only a virulence gene of IS257 among the 18 genes investigated. Moreover, it showed high bacteriocinogenic activity against different serotypes of L. monocytogenes, and its bacteriocin may be of great interest for controlling this pathogen. However, bacteriocin production when associated with pathogenic or opportunistic strains can be considered as a virulence factor, since it will improve survival abilities for the producer. Related to the observed results regarding the safety of the investigated strain, production of bacteriocin, and potential beneficial features, the S. epidermidis ST0409KOC strain is a strong candidate for use as a probiotic in different applications, and further studies are needed.

Bacteriocinogenic Staphylococcus epidermidis ST0409KOC was isolated from cheese and characterized as bacteriocin‐producing with strong activity versus Listeria monocytogenes and other pathogens. S. epidermidis ST0409KOC can be considered a safe strain regarding its virulence genetic background, presenting only a single virulence gene of IS257 among the 18 genes investigated.