Medical Management of Endocarditis Caused by Stenotrophomonas maltophilia: A Case Report

Abstract

A 44-year-old female was found to be systemically ill at dialysis and admitted to the hospital. Days into the hospitalization, her blood cultures from dialysis were positive with Stenotrophomonas maltophilia bacteremia with a levofloxacin minimum inhibitory concentration (MIC) of 1. She was discharged on ciprofloxacin 500 mg orally (PO) daily on hospital day 2 to complete a 14-day course. Weeks later, she was again found to be bacteremic at dialysis and sent back to the hospital. She was started on empiric antibiotics upon admission until further identification. Blood cultures again revealed S. maltophilia with a levofloxacin MIC of 32. Antibiotics were tailored to trimethoprim/sulfamethoxazole (TMP-SMX) until susceptibilities for additional agents were available. Further workup revealed mitral valve endocarditis. She was subsequently discharged on both minocycline 100 mg PO every 12 hours and TMP-SMX 1 DS PO daily with a planned duration of 6 weeks. Due to ongoing readmissions for hyperkalemia, TMP-SMX was discontinued and her regimen was modified to ceftazidime 1 g intravenously (IV) after HD plus minocycline 100 mg PO every 12 hours. She was deemed clinically and microbiologically cleared based on follow-up assessments. To our knowledge, this is the first case of S. maltophilia endocarditis treated with oral minocycline in combination with another antibiotic.

Keywords: Stenotrophomonas maltophilia; endocarditis; minocycline.