title: Comparison of Nonculture Blood-Based Tests for Diagnosing Invasive Aspergillosis in an Animal Model.
abstract: The EuropeanAspergillusPCR Initiative (EAPCRI) has provided recommendations for the PCR testing of whole blood (WB) and serum/plasma. It is important to test these recommended protocols on nonsimulated "in vivo" specimens before full clinical evaluation. The testing of an animal model of invasive aspergillosis (IA) overcomes the low incidence of disease and provides experimental design and control that is not possible in the clinical setting. Inadequate performance of the recommended protocols at this stage would require reassessment of methods before clinical trials are performed and utility assessed. The manuscript describes the performance of EAPCRI protocols in an animal model of invasive aspergillosis. Blood samples taken from a guinea pig model of IA were used for WB and serum PCR. Galactomannan and β-d-glucan detection were evaluated, with particular focus on the timing of positivity and on the interpretation of combination testing. The overall sensitivities for WB PCR, serum PCR, galactomannan, and β-d-glucan were 73%, 65%, 68%, and 46%, respectively. The corresponding specificities were 92%, 79%, 80%, and 100%, respectively. PCR provided the earliest indicator of IA, and increasing galactomannan and β-d-glucan values were indicators of disease progression. The combination of WB PCR with galactomannan and β-d-glucan proved optimal (area under the curve [AUC], 0.95), and IA was confidently diagnosed or excluded. The EAPRCI-recommended PCR protocols provide performance comparable to commercial antigen tests, and clinical trials are warranted. By combining multiple tests, IA can be excluded or confirmed, highlighting the need for a combined diagnostic strategy. However, this approach must be balanced against the practicality and cost of using multiple tests.
authors.affiliation: PHW Microbiology, Cardiff, United Kingdom lewis.white@wales.nhs.uk.
authors.forename: P Lewis
authors.initials: PL
authors.lastname: White
authors.affiliation: San Antonio Center for Medical Mycology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
authors.forename: Nathan P
authors.initials: NP
authors.lastname: Wiederhold
authors.affiliation: Wuerzburg University, Wuerzburg, Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Loeffler
authors.affiliation: San Antonio Center for Medical Mycology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
authors.forename: Laura K
authors.initials: LK
authors.lastname: Najvar
authors.affiliation: Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Willem
authors.initials: W
authors.lastname: Melchers
authors.affiliation: San Antonio Center for Medical Mycology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Herrera
authors.affiliation: Hôpital Saint Louis, Paris, France.
authors.forename: Stephane
authors.initials: S
authors.lastname: Bretagne
authors.affiliation: San Antonio Center for Medical Mycology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Wickes
authors.affiliation: San Antonio Center for Medical Mycology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA.
authors.forename: William R
authors.initials: WR
authors.lastname: Kirkpatrick
authors.affiliation: Cardiff University, UHW, Cardiff, United Kingdom.
authors.forename: Rosemary A
authors.initials: RA
authors.lastname: Barnes
authors.affiliation: Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: J Peter
authors.initials: JP
authors.lastname: Donnelly
authors.affiliation: San Antonio Center for Medical Mycology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA South Texas Veterans Health Care System, San Antonio, Texas, USA.
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Patterson
mesh_terms: D000818:Animals; D001769:Blood / Q000382:microbiology; D003955:Diagnostic Tests, Routine / Q000379:methods*; D004195:Disease Models, Animal; D005690:Galactose / Q000031:analogs & derivatives; D006168:Guinea Pigs; D055744:Invasive Pulmonary Aspergillosis / Q000175:diagnosis*; D008297:Male; D008351:Mannans / Q000032:analysis*; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011509:Proteoglycans; D012680:Sensitivity and Specificity; D013997:Time Factors; D047071:beta-Glucans / Q000032:analysis*
chemical_list: D008351:Mannans; D011509:Proteoglycans; D047071:beta-Glucans; C012990:galactomannan; C010770:polysaccharide-K; D005690:Galactose