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Invasive aspergillosis : Update on conventional diagnosis Jacques Bille, MD Institut of Microbiology University Hospital Lausanne, Switzerland.

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Presentation on theme: "Invasive aspergillosis : Update on conventional diagnosis Jacques Bille, MD Institut of Microbiology University Hospital Lausanne, Switzerland."— Presentation transcript:

1 Invasive aspergillosis : Update on conventional diagnosis Jacques Bille, MD Institut of Microbiology University Hospital Lausanne, Switzerland

2 Invasive aspergillosis : update on conventional diagnosis The problems The disease is evolving Clinical signs/ symptoms are non specific Conventional diagnosis is insensitive or too late Non conventional diagnosis is "promising"

3 Invasive aspergillosis : update on conventional diagnosis The disease is evolving A continuum of clinical presentations New (?) hosts Underdiagnosed ante-mortem

4 Invasive aspergillosis : update on conventional diagnosis Hope, WW, Walsh TJ, Denning DW. The invasive and saprophytic syndromes due to Aspergillus species. Medical Mycology 2005, 43: S

5 Invasive aspergillosis : update on conventional diagnosis Clinical signs/symptoms are non specific fever dyspnea non productive cough hemoptysis chest pain pleural rib In a proper host rapidly progressive

6 Invasive aspergillosis : update on conventional diagnosis Conventional diagnosis direct examination of tissue of indirect clinical specimens (sputum, BAL) sputum/BALtissue unstainedwet prep ± KOH routine stainsGramHE fungal stainsGMS, PASGMS, PAS fluorescentCalcofluor white dyesUvitex 2B Blankophor

7 Invasive aspergillosis : update on conventional diagnosis In: Hope et al., Lancet Infectious Diseases 5: 609, 2005

8 Invasive aspergillosis : update on conventional diagnosis Histopathologic diagnosis of Aspergillosis Improvement by immunohistochemical detection Monoclonal antibodies WF-AF-1 (Dako) 1) EB-A1 2) Sensitivity in culture-proven cases : 89-94% Genus or species specific results 1) Choi JK et al., Am J Clin Pathol 121: 18, ) Pierard GE et al., Am J Clin Pathol 96: 373, 1991 Verweij PE et al., Am J Clin Pathol 49: 798, 1996

9 Invasive aspergillosis : update on conventional diagnosis In: Choi JK, Am J Clin Pathol 121: 18, 2004

10 Invasive aspergillosis : update on conventional diagnosis Culture Isolation:Sabouraud (+ antibiotics) Media blood agar, chocolate agar Identification :malt-extract, corn-meal agar Czapek agar Incubation temperature25-30°C improvement ? athmosphereaerobic duration2-6 weeks

11 Invasive aspergillosis : update on conventional diagnosis In: Andreoni et al., Medical Mycology Atlas

12 Invasive aspergillosis : update on conventional diagnosis Culture Can we improve the sensitivity ? (in tissue) What is the best indirect specimen ? Sputum or BAL What are the PPV of a positive culture for IA, and the sensitivity of culture to diagnose IA ?

13 Invasive aspergillosis : update on conventional diagnosis Performance of a diagnostic test Caveat –timing of sampling - evolution of the disease –per test vs per episode analysis –patient population –Prior antifungal prophylaxis or therapy

14 Invasive aspergillosis : update on conventional diagnosis Yield of culture for molds in histopathologic positive samples n= culture positive Autopsy samples % Surgical or biopsy tissue30930% Tarrand JJ et al., Am J Clin Pathol 2003; 119: 854

15 Invasive aspergillosis : update on conventional diagnosis Culture Can we do better ? Mimic physiologic termperature and decreased oxygen environment : 35°C, 6% O 2 -10% CO 2 significant increase of Aspergillus spp from autopsy tissue and various clinical samples (+ 31%) Tarrand JJ et al., J Clin Microbiol 2005; 43: 382

16 Invasive aspergillosis : update on conventional diagnosis Culture : BAL is better than sputum (?) Overall sensitivity 50% Adapted from Reichenberger et al., Bone Marrow Transplantation 1999; 24: 1195 Diagnostic yield of bronchoscopy specimen in histologically proven IPA No. of casesBronchoscopy diagnostic Albeda % Treger % Kahn % Saito % Levy % Mc Whinney % Saugier-Weber % Von Eiff % Horvath % Caillot % Baron % Reichenberger % Overall %

17 Invasive aspergillosis : update on conventional diagnosis The paradox of a positive sputum culture for Aspergillus low sensitivity for IA low specificity for IA Can we improve ?

18 Invasive aspergillosis : update on conventional diagnosis How to increase the PPV for IA of a positive sputum culture at (high) risk patient multiple positive samples 1) quantitative culture 1) 2) use of a score 2) 3) 1) Nalesnik et al., J Clin Microbiol 1980; 11: 370 2) Greub and Bille, Clin Microbiol Infect 1998; 4: 710 3) Bouza and Muñoz, J Clin Microbiol 2005; 43: 2075

19 Invasive aspergillosis : update on conventional diagnosis Positive predictive value of a positive sputum culture for IA Highly variable (15-77%) Depends on host factors allo BMT60% leukemia + neutropenia70-80% SOT20-60% HIV/AIDS14-20% Corticosteroids20% Perfect et al. (MSG), Clin Infect Dis 2001; 33: 1824 Yu et al., Am J Med 1986; 81: 249 Horvath and Dummer, Am J Med 1996; 100: 171

20 Invasive aspergillosis : update on conventional diagnosis Prospective assessment of the clinical signi- ficance of isolating A.fumigatus by culture 404 A.fumigatus positive cultures (260 patients) 90 (22.3%) from 31 (12%) patients with IA 6% if1+cult. 18% 2+ 38% 3+ 10%if 1-2score 40% % 5 Bouza et al., J Clin Microbiol 2005; 43: 2075 Score Criteriapoints Invasive procedure1 2 + cultures1 Leukemia2 Corticosteroids2 Neutropenia5

21 Invasive aspergillosis : update on conventional diagnosis Radiology 2 interesting recent findings : Systematic CTis more sensitive than galactomannan for early detection of IA 1) reduces the amount of antifungal therapy when combined to GM screening 2) Angio CT has a higher specificity than CT for IA 3) 1) Weisser et al., Clinical Infectious Diseases 2005; 41: ) Maertens et al., Clinical Infectious Diseases 2005; 41: ) Sonnet et al., Am J Roentgenol 2005; 184: 746

22 Invasive aspergillosis : update on conventional diagnosis Conclusions Conventional diagnosis of IA is : suboptimal indispensable genus, species AFST perfectible


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