A Case of Infective Endocarditis Caused by Community Acquired Methicillin-resistant Staphylococcus aureus (CA-MRSA)

Community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), which is genetically different from hospital-acquired MRSA, has been recognized as a novel pathogen. CA-MRSA usually induced skin or soft tissue infection. The prognosis of CA-MRSA infections would appear to be better than that of hospital acquired (HA)-MRSA infections. Recently the infective endocarditis caused by CA-MRSA has been reported, but these cases were rare in Japan. A woman in her 40s was admitted to another hospital because of fever and mild disturbance of consciousness. Cardiac echography was conducted to detect the focus of the fever, and vegetation was found at the mitral valve. She was transferred to our hospital to undergo further treatment including a surgical approach. Transesophageal echocardiography detected vegetation at the anterior leaflet of the mitral valve. Brain magnetic response imaging (MRI) showed multiple small infarctions. MRSA was detected several times from blood cultures. The staphylococcal cassette chromosome mec analysis of MRSA showed type IV,revealing that MRSA in this case was CA-MRSA. The patient was then diagnosed as having infective endocarditis (IE) with multiple cardioembolic cerebellar infarction caused by CA-MRSA. Further study found the disseminated lesions, such as pyogenic spondylitis, intramuclar and skin abcesses. At the same time, untreated diabetes mellitus was found and insulin therapy was started immediately. She was treated successfully with the administration of several antibiotics, the surgical removal of the vegetation and a mitral valve plasty. CA-MRSA is an emerging pathogen and has the capability to be one of the causes of IE.