title: Evaluation of galactomannan enzyme immunoassay and quantitative real-time PCR for the diagnosis of invasive pulmonary aspergillosis in a rat model.
abstract: Since there is no consensus about the most reliable assays to detect invasive aspergillosis from samples obtained by minimally invasive or noninvasive methods, 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. 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. The A. fumigatus DNA detection sequence was detected in the following number of samples from 12 immunosuppressed, infected rats examined on the scheduled days: day 1 (0/12), day 3 (0/12), day 5 (6/12), and day 7 (8/12) post-infection. The sensitivity and specificity of the qRT-PCR assay was 29.2% and 100%, respectively. Receiver operating characteristic curve (ROC) analysis indicated a Ct (cycle threshold) 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 Ct cut-off value was 1.40 (AUC, 0.919). The GM assay was more sensitive than the qRT-PCR assay in diagnosing invasive pulmonary aspergillosis in rats.
authors.affiliation: Department of Internal Medicine, Huang Pu Hospital of the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510700, P. R. China.
authors.forename: Jian-Cong
authors.initials: JC
authors.lastname: Lin
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Xing
authors.forename: Wen-Ming
authors.initials: WM
authors.lastname: Xu
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Pang
authors.initials: P
authors.lastname: Bo
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Niu
authors.forename: Chang-Ran
authors.initials: CR
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001232:Aspergillus fumigatus / Q000737:chemistry / Q000235:genetics / Q000254:growth & development; D003955:Diagnostic Tests, Routine / Q000379:methods*; D004195:Disease Models, Animal; D005690:Galactose / Q000031:analogs & derivatives; D007124:Immunoenzyme Techniques / Q000379:methods; D055744:Invasive Pulmonary Aspergillosis / Q000175:diagnosis*; D008351:Mannans / Q000032:analysis* / Q000276:immunology; D012372:ROC Curve; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D008351:Mannans; C012990:galactomannan; D005690:Galactose