Invasive aspergillosis : Update on conventional diagnosis Jacques Bille, MD Institut of Microbiology...
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Transcript of Invasive aspergillosis : Update on conventional diagnosis Jacques Bille, MD Institut of Microbiology...
Invasive aspergillosis :
Update on conventional diagnosis
Jacques Bille, MDInstitut of MicrobiologyUniversity HospitalLausanne, Switzerland
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"
Invasive aspergillosis : update on conventional diagnosis
The disease is evolving
A continuum of clinical presentations
New (?) hosts
Underdiagnosed ante-mortem
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 207-238
Invasive aspergillosis : update on conventional diagnosis
Clinical signs/symptoms are non specific
feverdyspneanon productive coughhemoptysischest painpleural rib
In a proper hostrapidly progressive
Invasive aspergillosis : update on conventional diagnosis
Conventional diagnosis
• direct examination of tissue of indirect clinical specimens (sputum, BAL)
sputum/BAL tissue
unstained wet prep ± KOHroutine stains Gram HE fungal stains GMS, PAS GMS, PASfluorescent Calcofluor white
dyes Uvitex 2BBlankophor
Invasive aspergillosis : update on conventional diagnosis
In: Hope et al., Lancet Infectious Diseases 5: 609, 2005
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, 20042) Pierard GE et al., Am J Clin Pathol 96: 373, 1991 Verweij PE et al., Am J Clin Pathol 49: 798, 1996
Invasive aspergillosis : update on conventional diagnosis
In: Choi JK, Am J Clin Pathol 121: 18, 2004
Invasive aspergillosis : update on conventional diagnosis
Culture
Isolation: Sabouraud (+ antibiotics)Media blood agar, chocolate agar
Identification : malt-extract, corn-meal agarCzapek agar
Incubationtemperature 25-30°C improvement ?athmosphere aerobicduration 2-6 weeks
Invasive aspergillosis : update on conventional diagnosis
In: Andreoni et al., Medical Mycology Atlas
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 ?
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
Invasive aspergillosis : update on conventional diagnosis
Yield of culture for molds in histopathologic positive samples
n= culture positive
Autopsy samples 23 12 52%
Surgical or biopsy tissue 30 9 30%
Tarrand JJ et al., Am J Clin Pathol 2003; 119: 854
Invasive aspergillosis : update on conventional diagnosis
Culture
Can we do better ?
Mimic physiologic termperature and decreased oxygen environment : 35°C, 6% O2 -10% CO2
significant increase of Aspergillus spp from autopsy tissue and various clinical samples (+ 31%)
Tarrand JJ et al., J Clin Microbiol 2005; 43: 382
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 cases Bronchoscopy diagnostic
Albeda 1984 15 14 5 36 %Treger 1985 16 12 8 67 %Kahn 1986 17 27 13 48 %Saito 1988 18 9 0 0 %Levy 1992 11 16 9 56 %Mc Whinney 1993 19 12 6 50 %Saugier-Weber 1993 2 10 3 30 %Von Eiff 1995 12 12 6 50 %Horvath 1996 8 29 11 38 %Caillot 1997 20 18 8 45 %Baron 1998 4 13 8 61 %Reichenberger 1999 9 23 7 30 %
Overall 195 84 43 %
Invasive aspergillosis : update on conventional diagnosis
The paradox of a positive sputum culture for Aspergillus
low sensitivity for IAlow specificity for IA
Can we improve ?
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: 3702) Greub and Bille, Clin Microbiol Infect 1998; 4: 7103) Bouza and Muñoz, J Clin Microbiol 2005; 43: 2075
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 BMT 60%leukemia + neutropenia 70-80%SOT 20-60%HIV/AIDS 14-20%Corticosteroids 20%
Perfect et al. (MSG), Clin Infect Dis 2001; 33: 1824Yu et al., Am J Med 1986; 81: 249Horvath and Dummer, Am J Med 1996; 100: 171
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% if 1+ cult.18% 2+38% 3+
10% if 1-2 score40% 3-470% 5
Bouza et al., J Clin Microbiol 2005; 43: 2075
ScoreCriteriapointsInvasive procedure 1 2 + cultures 1Leukemia 2Corticosteroids 2Neutropenia 5
Invasive aspergillosis : update on conventional diagnosis
Radiology
2 interesting recent findings :
Systematic CT • is more sensitive than galactomannan for early detection of IA1)
• reduces the amount of antifungal therapy when combined to GM screening2)
Angio CT has a higher specificity than CT for IA3)
1) Weisser et al., Clinical Infectious Diseases 2005; 41: 11432) Maertens et al., Clinical Infectious Diseases 2005; 41: 12423) Sonnet et al., Am J Roentgenol 2005; 184: 746
Invasive aspergillosis : update on conventional diagnosis
Conclusions
Conventional diagnosis of IA is :
suboptimal indispensable
genus, species
AFST perfectible