Enantioselective measurement of fungal D-arabinitol in the sera of normal adults and patients with candidiasis

A new method was used to measure D-arabinitol enantioselectively in the sera of 27 healthy adults and four patients with candidiasis. Arabinitol was measured by gas chromatography in serum that was treated with and without the Klebsiella pneumoniae enzyme D-arabinitol dehydrogenase, lactic dehydrogenase, NAD, and sodium pyruvate. Since enzyme treatment removed 98% of 0 to 20 μg of D-arabinitol per ml and none of 0 to 20 μg of L-arabinitol per ml from spiked sera, D-arabinitol could be determined from the difference in the treated and untreated samples. The concentrations of D- and L-arabinitol in serum from normal subjects were 0.22 ± 0.052 and 0.16 ± 0.055 μg/ml, respectively, and their D-arabinitol/creatinine and L-arabinitol/creatinine ratios were 0.024 ± 0.0089 and 0.017 ± 0.0053 (all means ± standard deviations). The infected patients all had markedly elevated serum D-arabinitol levels, but their L-arabinitol levels were either normal or proportionately much lower. The excess arabinitol in the sera of individuals with candidiasis is D-arabinitol, and use of enantioselective analytical methods should result in improved ability to diagnose and estimate the severity of candidiasis.