Conclusion
The literature presents only a few cases of MRSA IE not susceptible to glycopeptides in not drug addicted patients. This case shows the comparison of a highly-resistant MRSA after previous S. aureus osteomyelitis treated with glycopeptides. This is the first description of successful treatment of resistant-MRSA IE of the tricuspid valve complicated by multiple pulmonary septic infarction with quinupristin/dalfopristin

Background
Infective endocarditis was an invariably fatal infection before the availability of antimicrobials. A significant percentage of patients still succumb to it despite aggressive treatment especially when infected with virulent organisms such as Staphylococcus aureus. Overall, approximately 20% of S. aureus isolates in Europe are reported as methicillin-resistant, whereas in US hospitals the prevalence ranges from 33% to 55%. The past few years have also witnessed an increase in life-threatening community-acquired infections caused by MRSA. Most infections with VISA (vancomycin-intermediate S. aureus) and VRSA (vancomycin-resistant S. aureus) have occurred in a setting of heavy prior use of glycopeptides and other antimicrobial agents. Emergence of reduced vancomycin susceptibility and clinical resistance in S. aureus increases the possibility that currently available antimicrobial agents may become ineffective for treating systemic infections.

Case presentation
A 50 year-old non-insulin dependant diabetic male was admitted with the chief complaints of three-day fever and poor general status. He had a 3/6 diastolic murmur over the xyphoid process. Chest X-ray did not show abnormalities. Abdominal ultrasound showed splenomegaly. His past history included the following: In June 2000 he had a road traffic accident resulting in multiple trauma, requiring right above-the-knee amputation and orthopaedic fixation of the left lower limb. He later presented with multiple episodes of osteomyelitis of this limb treated with iv. antibiotics. Prosthetic shafts were removed in June 2002 and MRSA isolated. Three months later he presented with a spontaneous fracture of the limb and required new surgical fixation due to infectious pseudoarthrosis. MRSA was isolated again. In October 2003 he was re-operated and underwent auto-transplantation of corticospongiosa. During these episodes he was given teicoplanin, cotrimoxazole, rifampicin, tetracycline and quinolones at intervals of 7 to 20 days at another institution in a distant site. Table 1 shows the summary of the multiple events.