Impact of antifungal prophylaxis on the gastrointestinal yeast colonisation in patients with haematological malignancies

: Patients with haematological malignancies are at high risk for developing invasive Candida infections. They are often colonised with Candida spp. in the gastrointestinal (GI) tract. In order to prevent infection, the prophylactic use of antifungal agents has been established. The widespread use of fluconazole may lead to the emergence of resistant Candida isolates. We studied the yeast colonisation of the GI tract in patients with haematological malignancies receiving antifungal prophylaxis (AP) in comparison with healthy controls. The study cohort included 46 neutropenic patients with 52 stool samples under 52 episodes of AP and 110 healthy controls. The patients received amphotericin B orally (n = 8), amphotericin B and fluconazole (n = 7), amphotericin B and itraconazole (n = 5), fluconazole orally (n = 15) and itraconazole orally (n = 17). Yeasts were cultured from the stool samples of 63.5% of the patients and 60% of the controls with a mean yeast load of 1.6 x 10(3) and 0.4 x 10(3) cfu g(-1), respectively (P = 0.045). Patients and controls had a low faecal yeast load of 10(3) to 10(4) cfu g(-1) in 19.3% and 37.3%, respectively (P = 0.021), and yeast overgrowth of >10(5) cfu g(-1) in 28.9% and 10.9%, respectively (P = 0.004). The rate of Candida albicans was 32.6% and 54.1% in the patients and controls, respectively (P = 0.021). The rates of fluconazole-resistant yeast species were higher in the patient group than in the control group: C. glabrata 20.9% vs. 11.7% (P = 0.168), C. krusei 25.6% vs. 4.7% (P = 0.001). Not a single patient under AP suffered from proven or probable invasive candidosis. In conclusion, oral AP in haematological patients resulted in a higher colonisation rate with fluconazole-resistant Candida species but efficiently prevented invasive candidosis.