Abstract
Fungitell (Associates of Cape Cod) is a new Food and Drug Administration-approved, commercially available assay for the detection of (1-3)-ß-D-glucan (BG), a cell wall polysaccharide of a broad range of fungi, in clinical samples. The presence of BG in serum correlates clinically with certain invasive fungal infections (Odabasi et al., 2004; Ostrosky-Zeichner et al., 2005). However, there are very limited data on the use of Fungitell for serum BG detection to diagnose endemic mycoses. Amongst the dimorphic fungi associated with the endemic mycoses, Histoplasma capsulatum var. capsulatum and Blastomyces dermatitidis share a similar North American distribution. In the vast majority of individuals, infection will cause a transient influenza-like illness or can even be asymptomatic. In certain circumstances, these fungi can cause overt disseminated diseases. Detection of the infection can lag behind a clinically deteriorating patient, owing to inherent diagnostic difficulties (Faggi et al., 2001).
Using the Fungitell assay (), we recently tested different serum samples retrieved from patients with active proven histoplasmosis and blastomycosis. Eight out of nine sera collected from five patients with culture-confirmed active disseminated histoplasmosis tested positive for BG (mean value=859 pg ml1, range 1601895, cut-off value 80). BG values correlated with Histoplasma antigenuria levels (Pearson r2=0.88, P=0.03) (Fig. 1). One additional serum tested negative for BG, coming from a human immunodeficiency virus-infected patient with unexplained respiratory symptoms. The diagnosis was made retrospectively when a blood culture collected three months afterwards grew Histoplasma capsulatum.