C-193. An Unusual Case of Endocarditis Caused by Candida tropicalis that Emerged Resistant to Fluconazole during Antimicrobial Therapy

G. Turner, C. Kelley, M. Suseno, L. J. Kaplan, R. B. Thomson, Jr.;
Evanston Hosp. and Northwestern Univ. Feinberg Sch. of Med., Evanston, IL.

Infectious endocarditis is a life-threatening condition most commonly caused by Gram-positive bacteria. Fungal endocarditis accounts for approximately 5% of all infectious endocarditis cases, with Candida albicans being the most common etiology. We report a case of a 48-year-old male Pakistani patient with a history of rheumatic heart disease, mitral valve repair and autosomal dominant polycystic kidney disease with end-stage renal disease, who was seen in the Emergency Department with a one week history of fever and chills. The patient was admitted to the hospital, a subclavian dialysis catheter tip grew Candida tropicalis, and empiric treatment with fluconazole was initiated. After two days, the patient was switched to amphotericin B, when his clinical condition did not improve, and continued treatment with amphotericin B for a catheter site infection until discharge on day 6. Eight blood cultures during hospitalization were negative at the time of discharge. However, one of the eight blood cultures was reported positive for C. tropicalis after the patient’s discharge. An ophthalmology exam was performed and endophthalmitis was ruled out. When discharged, the patient was treated for a catheter-associated bloodstream infection with an additional two week course of fluconazole (MIC = 1 ug/ml). Four weeks after stopping fluconazole therapy, the patient was re-admitted to the hospital with dyspnea, cough, chest pain, and fever. Multiple blood cultures during this admission grew C. tropicalis, however, the fluconazole MIC was now 256 ug/ml. Transesophageal echocardiogram identified vegetations of the patient’s mitral valve leaflets. The valve was replaced, demonstrating gross vegetations and pseudohyphae consistent with Candida species microscopically. The patient is currently being treated with intravenous amphotericin B and has made clinical improvement. In summary, we report an unusual case of C. tropicalis endocarditis that may have resulted from an infected subclavian dialysis catheter tip. The C. tropicalis isolate appeared to develop in vivo and in vitro fluconazole resistance while the patient was being treated with fluconazole.