(WHS-P1.06) STAPHYLOCOCCUS EPIDERMIDIS FITNESS IN THE CHRONIC WOUND MICROENVIRONMENT IS DRIVEN BY ANTIMICROBIAL RESISTANCE TRAITS
Friday, May 17, 2024
10:30 AM – 11:30 AM East Coast USA Time
A perturbed microbiome with persistent wound infection by biofilm forming bacteria is characteristic of chronic wounds, including venous leg ulcers (VLUs). Staphylococcus epidermidis is the most abundant skin-resident bacteria primarily known to be beneficial to the host but is also recognized as an “accidental” pathogen in certain environments. As the role of S. epidermidis in the wound chronicity is still unclear, we performed an in-depth characterization of S. epidermidis isolated from chronic VLUs. We utilized a human ex vivo wound model to show that healthy, commensal strains of S. epidermidis were incapable of surviving the human ex vivo wound environment. However, S. epidermidis strains isolated from VLUs showed a biofilm-dependent induction of IL-1β, IL-8 and IL-6 and inhibition of wound re-epithelialization, correlating with the healing outcome of the corresponding VLU patients. Using whole genome sequencing, we found both commensal and VLU isolates of S. epidermidis had similar signatures for biofilm formation and adhesion, but only the VLU isolates demonstrated higher biofilm formation and extracellular matrix binding. A majority of the VLU patients tested (n=24) had a high prevalence of mupirocin and methicillin resistance genes, contributing to the emergence of treatment resistant virulent lineages in patients with non-healing ulcers. Our data emphasizes the need to develop therapeutics targeting bacterial attachment or mechanical removal by debridement rather than a bactericidal approach to infection in VLUs.