Stenotrophomonas maltophilia endocarditis of prosthetic mitral valve.

We present a 78-year-old woman with prosthetic valve endocarditis due to Stenotrophomonas maltophilia (S. maltophilia) 3 years after mitral valve replacement. Administration of sulfamethoxazole-trimethoprim was effective; however, it was discontinued because of side effects, which led to failure of antibiotic therapy. Complications of multiple cerebral infarction and paravalvular abscess developed. Although the prosthetic valve was removed 50 days after admission, she died 4 months after surgery. S. maltophilia has been increasingly being considered as a serious nosocomial pathogen. S. maltophilia endocarditis is rare; however, it should be recognized as a possible life-threatening disease in patients with prosthetic valve.