Successful treatment of methicillin-resistant Staphylococcus aureus osteomyelitis and persistent bacteremia using adjunctive ceftaroline fosamil to vancomycin: A case report.

BACKGROUND: Ceftaroline fosamil is a novel cephalosporin antibiotic effective against methicillin-resistant Staphylococcus aureus (MRSA). The FDA approved it in 2010 for the treatment of community-acquired pneumonia and acute bacterial skin and skin structure infections. However, there is a lack of comprehensive data evaluating its effectiveness in treating osteomyelitis. Therefore, we report a case of MRSA osteomyelitis with persistent bacteremia, initially treated with vancomycin, where ceftaroline fosamil was subsequently added due to persistently positive blood cultures.

CASE REPORT: We report a case of a 47-year-old male with a medical history of ischemic heart disease, heart failure with reduced ejection fraction, schizophrenia, hypertension, and type 2 diabetes mellitus who was admitted to the ICU with septic shock. Empiric treatment was initiated with meropenem and vancomycin. Vancomycin was given as 1000 mg IV every 24 h (18.8 mg/kg). Dosing was guided by serum vancomycin concentrations, with adjustments made by critical care clinical pharmacists to maintain target levels of 15-20 µg/mL (10-14 µmol/L). Over the following days, the patient was diagnosed with osteomyelitis, confirmed through CT and MRI imaging. Blood cultures subsequently grew MRSA. Despite 18 days of vancomycin therapy, he had persistent bacteremia, and the infectious disease team recommended the addition of ceftaroline fosamil to vancomycin to address the persistent bacteremia. Blood cultures turned negative within 24 h of initiating combination therapy.

CONCLUSION: Ceftaroline fosamil shows promise as an adjunct therapy alongside vancomycin for treating osteomyelitis complicated by persistent bacteremia caused by MRSA. Further studies with a larger sample size are needed to refine its application in the management of MRSA osteomyelitis.