Low (1,3)-beta-D-glucan in Candida parapsilosis infections
July 04 2016
(1,3)-beta-D-glucan (BGD) is a useful, rapid test for deep Candida infections, but is lower in those with C. parapsilosis infection. Drs Mikulska, Giacobbe and colleagues from Genoa, Italy evaluated 107 patients with positive blood cultures for a single Candida species against their BDG level (Fungitell).
The BDG cutoff used was >80 pg/ml. BDG was positive in 63 of 107 patients (59%) but remarkable differences in BDG levels among different species. For C. albicans (n=46) sensitivity was 72%, compared with 41% for C. parapsilosis (n=37); it was positive in 63% for other species. Median levels of BDG in patients with C. parapsilosis infection were 39pg/mL compared to 410 and 149 pg/mL for C. albicans and other species (p=0.003).
C,.parapsilosis on chromagar.
The BDG test was performed within 24 hours of blood culture only in 47% of patients and 25% of the patients received antifungals before BDG test. Two confusing variables, timing of the BDG test (number of patients where BDG tests were performed more than 24h after the blood culture) as well as the number of patients receiving antifungals before BDG testing were carefully evaluated with multivariate analysis to check the impact on the test.
Despite this, the differences found between the BDG levels among patients with a Candida positive blood culture clearly call for caution in recommending stopping antifungal therapy in all patients with low BDG levels.
The lower levels of BDG in serum in C. parapsilosis infections also requires caution when interpreting the results of (1,3)-b-D-glucan testing kits for the diagnosis of candiaemia caused by this fungus.