Persistence and evolution of linezolid- and methicillin-resistant Staphylococcus epidermidis ST2 and ST5 clones in an Italian hospital

Staphylococcus epidermidis is a member of the human skin microbiome. However, in recent decades multidrug-resistant and hospital-adapted lineages of S. epidermidis are increasingly involved in severe human infections associated to medical devices and in immunocompromised patient. Here, several linezolid- and methicillin-resistant S. epidermidis (LR-MRSE) strains collected from 2018 to 2021 from the same hospital were analyzed retrospectively.ST2 and ST5 clonal lineage was prevalent. Thirteen isolates were positive for the cfr gene. WGS analysis of relevant LR-MRSE displayed complex resistomes for the presence of several acquired antibiotic resistance genes including the SCCmec type III (3A) and SCCmec type IV (2B) in ST2 and ST5 isolates, respectively. Bioinformatics also showed a plasmid-location of the cfr gene.