Fungal infections in stem cell transplantation: epidemiology and therapy

Abstract

Invasive fungal infections (IFIs) are an increasingly important cause of infection-related mortality in stem cell transplantation (SCT). Mortality from IFIs remains high because of diagnostic limitations and has given rise to the concepts of empiric and pre-emptive, as opposed to targeted, antifungal therapy. Data from the 2010 US TRANSET consortium found that Aspergillus (43%) and Candida (28%) were the two most frequently encountered pathogen groups; Zygomycetes and Pneumocystis comprised 8% and 2%, respectively. The frequency of IFIs varies with SCT type with 12 month cumulative incidences highest for matched unrelated SCT and lowest for autologous SCT. Trends in susceptibility to antifungals have identified increasing azole resistance (with cross-resistance) amongst Candid a spp., ampho-tericin B resistance amongst certain moulds and azole resistance in Aspergillus and other moulds. Recommendations for targeted antifungal therapy of yeasts and mould infections of the Infectious Diseases of Society of American, European, and Australian and New Zealand Mycoses Interest Group are similar. Early intervention strategies include empirical therapy which reduces IFIfrequency but has not been shown to reduce mortality and has high costs and drug toxici-ties. Pre-emptive therapy attempts to harness clinical/radiological features in conjunction with fungal biomarkers to detect early disease but its advantage has not been documented.