Reviewing the importance and evolution of fungal infections and potential antifungal resistance in haematological patients

There is a growing body of evidence supporting the emergence of azole resistance in Aspergillus and Candida spp. and this may be of particular concern due to the potential implications in the management of invasive fungal infections occurring in immunocompromised hosts. The aim of present review was to describe the magnitude of the problem, summarising the epidemiology and potential impact of yeast and mould antifungal resistance in patients with haematological malignancies. The first cases of triazole-resistant Aspergillus fumigatus isolates were reported in 1997 in patients receiving itraconazole. More recently, a worrisome increase in the frequency of azole resistance has been reported, primarily in patients with chronic forms of pulmonary aspergillosis. However, estimates of azole resistance in haematological patients are poorly characterised, although widespread use of antifungal prophylaxis might favour the emergence of resistant isolates in this setting. A French study estimated a prevalence of 0.85% azole resistance among 118 A. fumigatus isolates collected in 89 haematological patients. More recently, the epidemiology of azole resistance in A. fumigatus in a cohort of 762 haematological patients who received an allogeneic haematopoietic stem cell transplantation (HSCT) in two German centres has been reported. A. fumigatus was identified in 27 HSCT recipients, and 8 patients (30%) had azole-resistant invasive aspergillosis. In summary, the rate of azole-resistant isolates in patients with haematological malignancies appears to be low; however, the paucity of data currently available requires further prospective surveillance programmes.