# Staphylococcus lugdunensis does not exert competitive exclusion on human corneocytes

## TL;DR

This study investigates how Staphylococcus lugdunensis interacts with other bacteria on human skin and finds it does not block other bacteria from attaching.

## Contribution

The study reveals that S. lugdunensis does not exhibit competitive exclusion on human corneocytes despite its antibiotic properties.

## Key findings

- S. lugdunensis attaches to human skin stratum corneum but not in a way that prevents other bacteria from attaching.
- S. lugdunensis is an efficient long-term colonizer despite reduced initial attachment.
- The attachment pattern of S. lugdunensis does not overlap significantly with S. aureus or S. epidermidis.

## Abstract

Human skin is our primary physical barrier and largest immune organ, and it also hosts a protective microbiota. Staphylococci are prominent members of the skin microbiota, including the ubiquitous coagulase-negative staphylococci (CoNS). The coagulase-positive Staphylococcus aureus is found as part of the microbiota, but it poses clinical concern due to its potential pathogenicity and antibiotic resistance. Recently, a CoNS, Staphylococcus lugdunensis, has been shown to inhibit S. aureus growth via the production of a novel antibiotic, lugdunin. In this study, we use human skin models to understand the spatial relationships between the CoNS Staphylococcus epidermidis and S. lugdunensis with S. aureus during colonization of human skin. We investigated the attachment patterns of the bacteria, both individually and in competition. Surprisingly, we found that attachment did not always correlate with colonization ability. S. lugdunensis exhibited significantly reduced attachment to human skin stratum corneum but was an efficient longer-term colonizer. S. lugdunensis had a distinct attachment pattern on human corneocytes, with no significant overlap, or competitive exclusion, with the other strains. S. lugdunensis is a potential probiotic strain, with a proven ability to suppress S. aureus. Before this potential can be realized, however, further research is needed to understand how this strain adheres and interacts with other bacteria in the human skin microenvironment.