Abstract
Background: Consensus on the most reliable assays to detect invasive aspergillosis from minimally or noninvasive samples has not been reached. In this study, we compared the efficacy of an enzyme-linked immunosorbent assay (ELISA) for galactomannan (GM) detection and quantitative real-time PCR assay (qRT-PCR) for the diagnosis of invasive pulmonary aspergillosis in a rat model. Methods: Neutropenic, male Sprague-Dawley rats (specific pathogen free; 8 weeks old; weight, 200 ± 20 g) were immunosuppressed with cyclophosphamide and infected with Aspergillus fumigatus intratracheally. Tissue and whole blood samples were harvested on days 1, 3, 5, and 7 post-infection and examined with GM ELISA and qRT-PCR. Results: On day 7, A. fumigatus DNA was amplified from 14 of 48 whole blood samples from immunosuppressed infected rats: day 1 (0/12), day 3 (0/12), day 5 (6/12), day 7 (8/12) post infection. The sensitivity and specificity of the qRT-PCR assay were 29.2% and 100%, respectively. Receiver operating characteristic curve (ROC) analysis indicated a Ct cut-off value of 15.35, and the area under the curve (AUC) was 0.627. The GM assay detected antigen in sera obtained on day 1 (5/12), day 3 (9/12), day 5 (12/12), and day 7 (12/12) post-infection, and thus had a sensitivity of 79.2% and a specificity of 100%. The ROC of the GM assay indicated that the optimal cut-off value was 1.40 (specificity, 100%; AUC, 0.919). Conclusions: The GM assay was more sensitive than qRT-PCR assay in diagnosing invasive pulmonary aspergillosis in rats.
Highlights
The prevalence of invasive fungal infections and consequent mortality has increased throughout the last 2 decades, and the reported mortality from an epidemiological study covering the period from 2002 to 2006 is 28.6% [1]
The efficacies of GM assay and quantitative real-time polymerase chain reaction (PCR) assay (qRT-PCR) assays for the detection of Aspergillus infection were evaluated in a well-established rat model of pulmonary invasive aspergillosis (IA)
The results showed that while both assays were 100% specific for the diagnosis of IA and GM assay exhibited much greater sensitivity and allowed for earlier detection
Summary
The prevalence of invasive fungal infections and consequent mortality has increased throughout the last 2 decades, and the reported mortality from an epidemiological study covering the period from 2002 to 2006 is 28.6% [1]. Traditional histopathological examination and fungal culture relying on invasive procedures are relatively insensitive and not commonly used in clinical diagnosis due to the challenges of sampling pulmonary fluids or tissues from critically ill patients. Consensus on the most reliable assays to detect invasive aspergillosis from minimally or noninvasive samples has not been reached. We compared the efficacy of an enzyme-linked immunosorbent assay (ELISA) for galactomannan (GM) detection and quantitative real-time PCR assay (qRT-PCR) for the diagnosis of invasive pulmonary aspergillosis in a rat model. Tissue and whole blood samples were harvested on days 1, 3, 5, and 7 post-infection and examined with GM ELISA and qRT-PCR. The GM assay detected antigen in sera obtained on day 1 (5/12), day 3 (9/12), day 5 (12/12), and day 7 (12/12) post-infection, and had a sensitivity of 79.2% and a specificity of 100%. Conclusions: The GM assay was more sensitive than qRTPCR assay in diagnosing invasive pulmonary aspergillosis in rats
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
