The primary question of this study is to understand if trimethoprim-sulfamethoxazole (TMP-SMX) is as effective as vancomycin for treating methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis.

Treatment of osteomyelitis is hampered by a paucity of evidence from prospective clinical trials with randomized treatment arms. Furthermore, previous randomized or observational trials have enrolled small numbers of subjects and thus often had non-definitive findings. One of the most common causes of osteomyelitis is Staphylococcus aureus. Over the past 10 years, rates of methicillin-resistant S. aureus (MRSA) have risen dramatically. Vancomycin is currently the treatment of choice for treating MRSA. While vancomycin is effective, it is only available in intravenous formulation and has renal and bone marrow toxicities. There is a critical need for effective, oral, cheap drugs for the treatment of MRSA. Trimethoprim-sulfamethoxazole (TMP-SMX) is a drug with several advantageous properties for the treatment of MRSA osteomyelitis. To address this question regarding optimal treatment of MRSA osteomyelitis, we designed a prospective, randomized trial comparing TMP-SMX with vancomycin for the treatment of MRSA osteomyelitis.

• Osteomyelitis
• Methicillin-resistant Staphylococcus Aureus

• Drug: trimethoprim-sulfamethoxazole
• Drug: vancomycin

• Active Comparator: trimethoprim-sulfamethoxazole
• Active Comparator: vancomycin

Inclusion Criteria:

1. Culture-proven MRSA, obtained in operating room or sterile biopsy procedure from bone site. The infection and sampling site can either be within bone or a deep soft-tissue site that is contiguous with bone; OR radiographic abnormality consistent with osteomyelitis in conjunction with a positive blood culture for MRSA.
2. Surgical debridement of infection site, as needed.
3. Subject is capable of providing written informed consent.
4. Subject is at least 18 years of age.
5. Subject capable of receiving outpatient parenteral therapy for 12 weeks.

Exclusion Criteria:

1. Hypersensitivity to TMP-SMX or vancomycin.
2. S. aureus resistant to TMP-SMX or vancomycin.
3. Osteomyelitis that develops directly from a chronic, open wound.
4. Polymicrobial culture(the only exception is if coagulase-negative staphylococcus is present in the culture and the clinical assessment is that it is a contaminant).
5. Subject has a positive pregnancy test at study enrollment.
6. Convicted felon currently in prison.
7. Baseline renal or hepatic insufficiency that would preclude administration of study drugs.
8. Active injection drug use without safe conditions to administer intravenous antibiotics for 3 months.
9. Anticipated use of antibiotics for greater than 14 days for an infection other than osteomyelitis.