Strains included in the study
The study sample consisted of 2 invasive MRSA isolates already molecularly characterized by standard genotyping methods internationally recognized to define MRSA clones. These strains were selected from a large collection of 15 MRSA strains phenotypically and molecularly (SCCmec -Spa type) characterized as previously reported (Campanileet al ., 2015; Bongiorno et al ., 2018) and tested for their ability to internalize and persist in MG-63 human osteoblasts (Bongiorno, Musso et al ., 2020).
The invasive isolate ATCC12598 (Cowan ST30-t076) (ATCC® Standards Development Organization, LGC Standards S.r.l., Sesto San Giovanni, MI, Italy) was used, as previously describe, as a control strain for invasion and persistence assays and for the statistical analysis of the results obtained with the Imaging Flow Cytometry (IFC) as previously reported (Bongiorno, Musso et al., 2020).