這是一個41歲女性靜脈毒癮患者有感染性心内膜炎及接受心臟瓣膜置換術病史，但仍持續靜脈藥物注射。這次又因多重微生物（Comamonas acidovoran及Candida parapsilosis）的感染性心内膜炎而住院。在治療過程中，由於抗生素及抗黴菌藥物治療無效，且持續性黴菌血症，病人再度接受心臟瓣膜置換術，手術後，發燒狀況隨即改善。病人在住院期間共接受約4星期fluconazole和6星期amphotericin B的抗生素治療，發燒和水腫等其他症狀改善，在住院第10週後病人出院。多重微生物的感染性心内膜炎是少見的，一般常發生在思有多種慢性疾病住院病人身上，且常伴隨血管内導管使用，發生時會有較高的死亡率。我們介紹此少見案例因長期靜脈藥物濫用，產生反覆性感染性心内膜炎，針對不同的致病菌給予長時問抗生素和抗黴菌藥物，並再次接受瓣膜置換術後，終讓病患順利出院。故當靜脈毒癮患者發生難以根治菌血症時，應將多重微生物的心内膜炎列入考慮。

We report a 41-year-old female intravenous drug abuser with a history of infective endocarditis and tricuspid valve replacement. She was admitted to our hospital again because of polymicrobial recurrent infective endocarditis. Blood culture revealed a mixed culture of Comamonas acidovorans and Candida parapsilosis. Fungemia persisted despite aggressive antifungal therapy. The patient underwent another valve replacement as a result. Fever subsided rapidly after the operation and the patient received 4 weeks of fluconazole and 6 weeks of amphotericin B treatment. She was discharged on the 10th week of admission. Polymicrobial infective endocarditis is a rare disease with high mortality rate that occurs in hospitalized patients with multiple systemic disease and intravenous device implantation. We herein described such case of polymicrobial infective endocarditis in an intravenous drug abuser with tricuspid valve replacement who required appropriate antifungal therapy with a second valve replacement for successful treatment. This unusual etiology should be considered in intravenous drug abusers with refractory bacteremia.