The Efficacy of Linezolid for Methicillin-resistant Staphylococcus aureus Infectious Endocarditis

We report a case of methicillin-resistant Staphylococcus aureus (MRSA) infectious endocarditis (IE) which was successfully treated with linezolid (LZD). The patient was a 44-year old woman. She was referred to our hospital because of fever of unknown origin. MRSA was detected from blood cultures and echocardiography revealed vegetation on the right coronary cusp of the aortic valve. She was diagnosed with MRSA endocarditis according to the Duke criteria, and was immediately give vancomycin (VCM) and isepamicin. Sixteen days after administration of VCM, she had a progressively increasing skin rash. It was considered a side effect of antibiotics and VCM was replaced with teicoplanin (TEIC). Eventually, LZD was given to her at 22 days after hospitalization because TEIC was not effective. LZD alleviated the fever and diminished the signs of vasculitis due to endocarditis within a week. LZD was continued for 4 weeks with cardiac failure medically controlled, and she underwent aortic valve replacement using a mechanical prosthetic valve. LZD was injected just before the operation and continued for 15 days postoperatively, followed by oral administration of levofloxacin. She was discharged 35 POD and no recurrence of the infection had been observed at 1 year after the surgery. LZD could be an alternative therapy for MRSA endocarditis, but further examinations are warranted to determine the most appropriate regimen.