The plasmin-sensitive protein gene pls which was found to be a virulence factor in mouse septic arthritis model is encoded by the staphylococcal cassette chromosome mec type I in MRSA that also encodes the methicillin-conferring mecA and further genes and has been found to stimulate BF formation (Bleiziffer et al., 2017). Here, CTSC is linked to bacterial arthritis.