A case of bloodstream co-infection of Saccharomyces cerevisiae and Candida glabrata while using micafungin

BACKGROUND: Saccharomyces cerevisiae is ubiquitous in the gastrointestinal tract and known as brewer's or baker's yeast. We experienced a case of S. cerevisiae and Candida glabrata co-infectious bloodstream infection. It is rare to detect both S. cerevisiae and Candida species in blood cultures together. CASE: We treated a 73-year-old man who developed a pancreaticoduodenal fistula infection after pancreaticoduodenectomy. The patient had a fever on postoperative day 59. We took blood cultures and detected C. glabrata. Thus, we started micafungin. On postoperative day 62, we retested blood cultures, and detected S cerevisiae and C. glabrata. We changed micafungin to liposomal amphotericin B. Blood cultures became negative on postoperative day 68. We changed liposomal amphotericin B to fosfluconazole and micafungin because of hypokalemia. He got well, and we terminated antifungal drugs 18 days after the blood cultures became negative. CONCLUSION: Co-infection with S. cerevisiae and Candida species is rare. In addition, in this case, S. cerevisiae developed from blood cultures during micafungin administration. Thus, micafungin may not be effective enough to treat S. cerevisiae fungemia, although echinocandin is considered one of the alternative therapy for Saccharomyces infections.