The MRSA strain of our patient was also tested positive for sei, fnbA and hlg. Fibronectin-binding proteins (FnBPA and FnBPB) encoded by fbpA and fbpB genes play a role in enhanced bacterial adherence to fibronectin and invasion of host cells including epithelial cells and fibroblasts and were significantly more frequently detected in S. aureus invasive strains (responsible for osteomyelitis, septic arthritis and endocarditis) compared with nasal carriage isolates[5,8]. This evidence concerns the gene FN1 and bacterial arthritis.