Fungal sepsis in the ICU: are we doing better? Trends in incidence, diagnosis, and outcome.

Abstract

Despite the availability of broad-spectrum antifungal agents, fungal sepsis remains an issue in Intensive Care Unit (ICU) patients. In terms of occurrence rates, the most important fungal infections are invasive candidiasis and invasive pulmonary aspergillosis. Early diagnosis is essential to optimize the chances of survival. As clinical rules based on risk factor assessment lack specificity, early initiation of antifungal therapy depends on fast and reliable diagnostics. Blood cultures or histopathologic evidence is the gold standard but blood cultures lack sensitivity and biopsy sampling may include substantial risk in critically ill patients. Non-culture-based diagnosis tools have therefore arisen as a smart way to detect earlier and/or more accurately the patients with on going fungal infection. For diagnosing invasive candidiasis, three assays (beta-D-glucan and mannan antigen detection, and polymerase chain reaction) yield promising predictive values, albeit that specificity remains an issue. In the absence of biopsies, invasive pulmonary aspergillosis can be diagnosed in nonneutropenic ICU patients by galactomannan antigen detection in broncho-alveolar lavage fluid. Aspergillus colonization of the respiratory tract can be discriminated from invasive disease by means of a clinical algorithm with high sensitivity but only moderate specificity. The incidence of invasive candidiasis has been stable over the past decades, but an alarming trend towards more non-albicans Candida species and reduced susceptibility is observed. Given the problematic diagnosis of invasive aspergillosis no reliable trend data are available. Outcome following fungal sepsis remains cumbersome. Given the availability of potent antifungal agents any progress in survival is likely to come from a more timely diagnosis.