Comparison of PCR, (1→3)‐β‐d‐glucan and galactomannan assays in sera of rats with experimental invasive aspergillosis

Abstract

We compared PCR, galactomannan detection assay using a latex agglutination test and (1-->3)-beta-D-glucan detection assay in detecting infection in rats experimentally infected with Aspergillus fumigatus. On day 2 after inoculation, (1-->3)-beta-D-glucan and nested PCR were positive for 80%, while galactomannan detection assay was positive for 60%. In addition, the positive result of nested PCR (87.5%) was higher than those of galactomannan detection assay (75%) and (1-->3)-beta-D-glucan (71.4%) on day 3 after inoculation. The sensitivity of nested PCR was superior to those of galactomannan detection assay and (1-->3)-beta-D-glucan detection assay. The three diagnostic tests were compared with histopathological findings, and the sensitivity of three diagnostic tests was correlated with histopathological changes. In addition, the elevated levels of (1-->3)-beta-D-glucan paralleled the development and progression of pulmonary aspergillosis. Our results indicate that a combination of two or three of these tests seems to provide a rapid diagnosis of invasive aspergillosis and assist in the evaluation of the development and severity of invasive aspergillosis.

Conventional or molecular measurement ofAspergillusload

“…Similarly, false negatives of b-glucan levels in histologically proven infection have been reported in studies using rat models of invasive pulmonary aspergillosis and b-glucan levels in the serum appear to rise later during infection than do galactomannan levels [49,50]. The question of appropriate cutoff value to use for the b-glucan assay with animal models also is yet to be decided, which is relevant since the sensitivity of both galactomannan and b-glucan assays have been reported to be lower than for PCR [49]. One aspect that should be further investigated, and could be problematic when using galactomannan as a marker of fungal burden in preclinical drug studies is the increase of galactomannan in serum after treatment.…”

Comparison of galactomannan, beta-D-glucan, and Aspergillus DNA in sera of high-risk adult patients with hematological malignancies for the diagnosis of invasive aspergillosis

“…In this study, the sensitivity of Aspergillus DNA was 90% and the specificity in patient sera was 73.3%. It is possible to find numerous studies that compare GM, BDG, and specific DNA tests (22)(23)(24)(25)(26)(27)(28)(29)(30). In most of these studies, standard methods were used for GM and BDG, whereas different DNA search methods were used, as mentioned above.…”

“…We suggest that rather than type and amount of sample or extraction method used, primary probes and PCR format are more important in terms of sensitivity. Similar to sensitivity, various PCR formats had a specificity of 40%-100% (22)(23)(24)(25)(26)(27)(28)(29)(30). Nevertheless, due to decrease in contamination, highest specificity was achieved by RT-PCR.…”

Detection of Aspergillus fumigatus‐specific DNA, (1–3)‐β‐d‐glucan and galactomannan in serum and bronchoalveolar lavage specimens of experimentally infected rats

“…11 In contrast to BDG and GM results, detection of A. fumigatus DNA by nPCR in our rat model was not as sensitive as has been reported in some previous experimental studies. [16][17][18] Hashimoto et al [16] found that on day 2 after inoculation, the combined sensitivity of BDG and nPCR was 80%, while GM alone was positive in only 60% of rats. In contrast, on day 3 after inoculation, nPCR showed a sensitivity of 88%, whereas GM and BDG had a sensitivity of 75% and 71% respectively.…”