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Medical and Pathogenic Mycology Fungal ABC’s. Medical Mycology: Clinical Classification. Yeasts Systemic disease, pulmonary disease absent or subclinical Dimorphic fungi Primary pulmonary disease with dissemination prominent part of disease Molds - PowerPoint PPT Presentation
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Medical and Pathogenic Mycology
Fungal ABC’s
Medical Mycology: Clinical Classification
• Yeasts Systemic disease, pulmonary disease absent or
subclinical• Dimorphic fungi Primary pulmonary disease with dissemination
prominent part of disease• Molds Primary pulmonary disease with dissemination
less common
• Immunosuppressed patients only• Pulmonary infection by inhalation of airborne
spores with subsequent dissemination• Very aggressive, destructive• Aspergillus most common (>80%) Aspergillus fumigatus most common species
• Others Rhizopus, Absidia, Mucor (Zygomycetes) Penicilllium Pseudallescheria boydii
Invasive Mold Infections
Aspergillus fumigatus
• Ubiquitous mold• Found on decaying
material • Produces large
amount of airborne conidia
• On average at 100 to 1000 conidia are inhaled daily
A
B C D
E
Flow
G
H
I KJ L
F
Flow
G
H
I KJ L
FFlow
G
H
I KJ L
F
Flow
G
H
I KJ L
F
Alveolar Infection
Angioinvasion
Dissemination
18%63%
12%
7%BMT/HemeSOTAIDS/ImmunePulm
Marr KA et al. Blood 2002;100:4358-66; Lin SJ et al. Clin Infect Dis. 2001;32:358-66.
SOT = solid organ transplant
• Hematologic malignancy• HSCT (especially allogeneic)
Host variables (age, underlying disease) Transplant factors (source of stem cells) Late complications (GVHD, corticosteroids, secondary neutropenia)
• Solid-organ transplant• Advanced HIV disease
Invasive Aspergillosis Risk Groups - Risk Factors
PG Pappas: Transplant Associated Infection Surveillance Network
Time to Onset of IFI After HSCT
0
20
40
60
80
100
120
Early Onset (0-30 days) Intermediate Onset (30-60 days) Late Onset (90+ days)
IACandidiasisFusariumOther mouldPCPUnspec. mouldZygomycetes
# of
UFU
’s
0.0
0.2
0.4
0.6
1981 1986 1991 1996
CandidiasisAspergillosisOther Mycoses
Rat
e pe
r 100
,000
pop
ulat
ion
McNeil MM et al. Clin Infect Dis. 2001;33:641-7.
Invasive Mycotic Diseases 1980 – 1997 Trends in Mortality
Year
Aspergillosis+357%
Candidiasis
Other Mycoses+329%
Invasive Aspergillosis in CanadaEmerging Epidemiology:
Ascioglu S et al. Clin Infect Dis. 2002;34:7-14.
The Diagnostic Challenge – IA
Proven• Histopathology and/or• Growth in culture from tissue biopsy or aspirate from a
sterile site
Probable
• Presence of 1 host factor criterion, 1 clinical feature and microbiological evidence (includes galactomannan)
• Culture from sputum or BAL in immunocompromised patient with clinical evidence of infection
“The problem of uncertainty cannot be disregarded as if it does not exist…”
EORTC International Consensus
Possible
• At least 1 host factor criterion Neutropenia Persistent fever despite antibiotics in high-risk patients Signs and symptoms of GVHD Prolonged corticosteroid use
Ante Mortem Screening: (1) Regular galactomannan testing (2) CT scans
Sinko et al. Transpl Infect Dis 2008: 10: 106 -109
Autopsy-Proven IFD ConfirmsUnder-Diagnosis of IFD
•Two-site autopsy study of 97 allogeneic stem cell recipients
4
3
1
0
10
6
2 2
0
2
4
6
8
10
12
Total Aspergillosis Candidiasis Mucromycosis
Ante MortemPost Mortem
IFI D
eath
s
Perlroth J et al. Med Mycol. 2007;45:321-46.
Diagnostic MethodsCT Scan Nodules or patchy consolidations Halo sign: attenuated area around a nodule
Specific to IA? - in the setting of immunocompromise
Sensitivity varies with timing relative to diagnosis (high early)
(1,3)-ß-D-glucan assay Excellent negative predictive value False positives:
Albumin Immunoglobulin Hemodialysis
Galactomannan assay Sensitivity 0.73, specificity 0.81 (proven IA) False positives:
Lowered threshold for test positivity Bifidobacterium lipoglycan Concurrent use of ß-lactam antibiotics,
particularly piperacillin-tazobactam
PCR detection of fungal DNA Sensitivity 100% for IA (preceding
symptoms by a median of 2 days) Requires further standardization
and validation
Galactamannan (GM) Assay
• GM is a carbohydrate constituent of the fungal cell wall and is released during hyphal growth
• Commercial, FDA approved sandwich EIA for detection of circulating A. fumigatus GM
• Can be used on serum or BAL fluid• Cutoff for positive is an index of 0.5 (serum)• May be detected 5-8 days before symptoms
Utility and Limitations • Serum FDA literature - Sensitivity 80.7%, Specificity 89.2% Meta analysis - Sensitivity 73% and Specificity 81% Most useful in serial sampling Highest sensitivity in neutropenic patients
• BAL Cutoff 0.5 – Sensitivity 100%, Specificity 78% Cutoff 2.0 – Sensitivity 100%, Specificity 93.2% GM > 2 associated with a 4.68 CHR of death
Protocol for MUHC
1. Presumptive diagnosis of IA:• Testing on request of adult inpatients with at least one risk
factor for IA and at least one clinical criteria consistent with IA 2. Pre-emptive screening:• Routine screening of all high risk inpatients on hematology
wards• Sera will be collected three times per week (Mon-Wed-Fri)• Assays will be run twice weekly (Tues-Thurs).
Case51 year old womanApril 2010 AML Induced with FLAG-IDA CR
March 2011 Allo HSCT from brother
CaseSeveral complications GVHD (Grade III) – liver skin and bowel CMV positive April 2011 until Dec 2011
Multiple antivirals used including gancyclovir, foscarnet and cidofivir
EBV PCR positive April 2011, Rituximab given Dec 2011
Case Admitted Dec 2011 with fevers 7 d after
rituximab S. bovis bacteremia (Rx Ceftriaxone) RSV + in nasal swab – (Rx Ribivarin) HHV-6 PCR positive on blood CMV colitis
Relative stable by Jan 1 2012 and afebrile
Days4
Days
Voriconazole
Inci
denc
e of
IA
McGill University: Incidence of IAAML and Allogeneic Stem Cell Transplant patients Pre-galactoamman
Inci
denc
e of
IA
McGill University: Incidence of IAAML and Allogeneic Stem Cell Transplant patients Post-galactomannan
Rates of Invasive Aspergillosis
Centre Population IA Incidence (%)
Maisonneuve Rosemont Hospital
Allogeneic HSCT 15
Acute Leukemia 8.9
Vancouver General Hospital Allogeneic HSCT 18.8
Hotel Dieu Quebec AML 17.8
Invasive Fungal InfectionManagement
Azoles
ß-1, 3 glucanpolysaccharide
Cell MembranePhospholipid bilayer
Ergosterol
Antifungal Agents - Sites of Action
EchinocandinsAmpho B
Adapted from Metcalf SC, Dockrell DH. J Infect. 2007;55:287-99.
Drug Classes and Agents
Polyenes• Amphotericin B (AMB)• Lipid-based formulations
ABLC ABCD L-AMB
Expanded-spectrum azoles• Voriconazole• Posaconazole• Ravuconazole*
Azoles• Fluconazole• Itraconazole
Echinocandins• Caspofungin• Micafungin• Anidulafungin
*Not yet approvedABLC = Amphotericin B lipid complex; ABCD = Amphotericin B colloidal dispersion; L-AMB: Liposomal amphotericin B
Metcalf SC, Dockrell DH. J Infect 2007;55:287-299; Petrikkos G, Skiada A. Internat J Antimicrob Agents 2007;30:108-117
Wingard JR. Best Pract Res Clin Haematol 2007;20:99-107; Bow EJ. Hematol. 2006;1:361-7.
IFI Management
Nodisease
Markers
Signs & symptoms
Full-blown disease
Sequelae
Dis
ease
pro
gres
sion Prophylactic
Preemptive
Therapy
Empirical
Asymptomatic high-risk patient
Asymptomatic + colonization OR novel diagnostic
High risk: Antibiotic + fever
Evidence of infection+ clinical disease
0
20
40
60
80
100
0 2 4 6 8 10 12
Herbrecht R et al. N Engl J Med. 2002;347:408-15.
70.8%
57.9%
Survival at 12 weeks
Voriconazole vs. Amphotericin BIA Primary Therapy
Pat
ient
s S
urvi
ving
(%)
WeeksNo. at Risk
Voriconazole 144 131 125 117 111 107 102Amphotericin B 133 117 99 87 84 80 77
P=0.02
Siwek GT et al. Clin Infect Dis. 2004;39:584-7; Scott LJ, Simpson D. Drugs 2007;67:269-298
Voriconazole
Caveats No activity against
Zygomycetes Erratic
pharmacokinetics Drug interactions Hepatotoxicity Visual toxicity
0
2
4
6
8
10
12
Pre-Voriconazole
Post-Voriconazole
AspergillusZygomycetes
Cum
ulat
ive
Inci
denc
e (%
)
Maertens J et al. Clin Infect Dis. 2004;39:1563-71.
IA Salvage TherapyCaspofungin 83 evaluable patients
refractory to or intolerant of Ampho B, lipid formulations or triazoles 86% refractory, 15% intolerant 48% hematologic malignancy, 25% HSCT
45% favourable response, including 50% with pulmonary aspergillosis 23% with disseminated aspergillosis
Excellent safety profile
Early Intervention is Associated with Lower Mortality
Von Eiff et al. Respiration. 1995;62:341-347.
Retrospective analysis of the timing of empiric antifungal treatment for 33 cases of invasive aspergillosis between 1987 and 1992
0102030405060708090
Mor
talit
y, %
<10 days >11 daysTime from onset of pneumonia to initiation of
antifungal therapy
Morrell M et al. Antimicrob Agents Chemother. 2005;49:3640-5.
Initiation of Therapy
Early Therapy Better Outcomes
"Clinical trial data indicate rapidity of therapy initiation is an important and independent determinant of outcome."
M. Morrell
Bow EJ. Hematol. 2006;1:361-7.
IFI Management
Nodisease
Markers
Signs & symptoms
Full-blown disease
Sequelae
Dis
ease
pro
gres
sion Prophylactic
Preemptive
Therapy
Empirical
Asymptomatic high-risk patient
Asymptomatic + colonization OR novel diagnostic
High risk: Antibiotic + fever
Evidence of infection+ clinical disease
Wingard JR. Best Pract Res Clin Haematol 2007;20:99-107; Bow EJ. Hematol 2006;1:361-367; Pizzo Am J Med. 1982:72;101-11; EORTC Am J Med. 1989;86:668-72.
• Treat all neutropenic patients with persistent fever despite broad-spectrum antibiotics
Empirical Therapy
Pros High mortality Difficulties in diagnosis Treat undetected infection May reduce systemic
mycoses (Pizzo) May reduce mortality
(EORTC)
Cons Over-treatment Fever is non-specific Side-effects and cost Difficulties in diagnosis
Infected patients: too little treatment
Uninfected patients: too much treatment
Early Trials• Pizzo Am J Med 1982 First comparative evaluation of empiric
antifungal therapy Enrollment Criteria
Fever for 7d after antimicrobials started, PMN<500 Predominately pediatric population (mean age 16)
Randomized to stopping all abts, no change or 0.5mg/kg/d AmB
Pizzo - Outcomes
No Δ +AmB D/C Rx
# pts 16 18 16
Candida 4(3) 0 1
Mold 2 1 1
Infectious Complications 7(6) 2 9
Survival 11 15 11
Time to defervesce 7-8 3-5d 11-12d
* Minimal renal toxicity
EORTC Trial
• Larger study of empiric AmB use in febrile neutropenics
• Enrollment Adult population Fever for 4 days after antibacterials started PMN<1000
• Randomized to empiric AmB 0.6mg/kg/d or 1.2mg/kg/2d
EORTC - Outcomes
No Δ +AmB
# pts 64 68
Candida 4 1
Mold 2 0
Survival 79% 84%
Response (fever) 53 69
Walsh T et al. N Engl J Med. 2002;346:225-35; N Engl J Med. 2004;351:1391-1402.
Empirical Therapy
VORN=415
L-AMBN=422
Point Estimate for Percent Difference
(95% CI)Overall responseno. (%)
108 (26%)
129 (30.6%)
-4.5 (-10.6 to 1.6)P=NS
Breakthroughfungal infection
8(1.9%)
21(5.0%) P=0.02
Voriconazole or Caspofungin vs L-AMB
CASN=556
L-AMBN=539
Point Estimate for Percent Difference
(95% CI)Overall responseno. (%)
190 (33.9%)
181 (33.7%)
0.2 (-5.6 to 6.0)Non-inferiority
Absence of breakthroughfungal infection
29 (5.2%)
24 (4.5%)
P=0.56
Empiric therapy - summary
Cons• Original evidence for efficacy is weak• Fever is not specific and not sensitive in hematology
population• 50% of GM+ patients are afebrile• Institution of highly active mold prophylaxis
reduces mortality, pulmonary infiltrates but NOT fever
• Overall success in high risk patients is sub-optimal
• So what else can we do?
Bow EJ. Hematol. 2006;1:361-7.
IFI Management
Nodisease
Markers
Signs & symptoms
Full-blown disease
Sequelae
Dis
ease
pro
gres
sion Prophylactic
Preemptive
Therapy
Empirical
Asymptomatic high-risk patient
Asymptomatic + colonization OR novel diagnostic
High risk: Antibiotic + fever
Evidence of infection+ clinical disease
Thoracic CT scan (± CT sinus)
Maertens J et al. Clin Infect Dis. 2005;41:1242-50.
Incorporation of Diagnostic TestsPreemptive Therapy
High-risk hematology patients (all received Candida prophylaxis, fluconazole 400 mg/day)
Daily GM monitoring and clinical evaluation
>5 days of unexplainedneutropenic fever
refractory toantibiotics or relapsing
Characteristic of invasivemycosis: ‘halo-sign’
Broad-spectrumantifungal therapy
OD index2 x ≥ 0.5
Bronchoscopy with BAL
Positive culture or microscopy (molds)
New infiltrate onchest X-ray or
signs/symptoms ofinvasive mycosis
Atypical lesion
Normal
Continued monitoringNo antifungal therapy
ThoracicCT&
BAL
+ -
9.0%
*2.7%
0%
5%
10%
15%
20%
Empirical, n=150 Pre-emptive, n=143
% o
f pat
ient
s
*p<0.02
97.0% 95.0%
0%
20%
40%
60%
80%
100%
Empirical, n=150 Pre-emptive, n=143
% o
f pat
ient
s
p=ns
Overall survival Proven and probable IFI
Cordonnier et al. CID 2009
Empirical vs Preemptive antifungal therapy in high risk neutropenic patients
Preemptive Therapy Does Not Reduce IA Mortality
If earlier is better…
Is prevention best?
Bow EJ. Hematol. 2006;1:361-7.
IFI Management
Nodisease
Markers
Signs & symptoms
Full-blown disease
Sequelae
Dis
ease
pro
gres
sion Prophylactic
Preemptive
Therapy
Empirical
Asymptomatic high-risk patient
Asymptomatic + colonization OR novel diagnostic
High risk: Antibiotic + fever
Evidence of infection+ clinical disease
0.00
0.25
0.50
0.75
1.00
0 1 2 3 4 5 6 7 8 9
Placebo
Fluconazole 400 mg/d
Sur
viva
l Pro
babi
lity
Years After TransplantMarr KA, et al. Blood. 2000;96:2055-2061.
Related and Unrelated Donor Transplants
P = .0018
HSCT indicates hematopoietic stem cell transplant.
Fluconazole Prophylaxis in HSCT•Evidence for Long-term Survival
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 10 20 30 40 50 60 70
Adapted from van Burik JA, et al: Clin Infect Dis 2004; 39(10):1407-16.
Pro
porti
on o
f pat
ient
s w
ith tr
eatm
ent s
ucce
ss
Time to treatment failure (days since first dose of study drug)
micafungin (n = 425)Fluconazole (n = 457)
P = 0.025, by the log rank test
Overall Treatment Success•Micafungin vs. Fluconazole
Voriconazole vs. Fluconazole
*Proven + probable + presumptiveAdapted from Wingard JR, et al: Blood epub 2010
Subjects: 600 standard-risk allogeneic blood and marrow transplant patients
p=0.12
p=0.49
Voriconazole vs. Itraconazole: Improvit489 allogeneic stem cell transplant patients
N = 602 Chemotherapy& prophylaxis
Chemotherapy & prophylaxis (if needed)
Day 100postrandomization
Posaconazole (n = 304)
Fluconazole or Itraconazole (n = 298)
Primary end point time period
Secondary end point time period
Cornely OA et al. N Engl J Med 2007;356:348-59.
Study Design
Antifungal Prophylaxis: NeutropeniaPosaconazole vs Fluconazole / Itraconazole
4 (1%)
(5%) 14
2 (1%)
(2%) 7
(9%) 26
33 (11%)
(7%) 20
25 (8%)
0
5
10
15
20
25
30
35
40
All IFIs* Aspergillosis All IFIs Aspergillosis†
* P<0.001; † P= 0.003
Treatment Phase 100 Day Period After Randomization
Primary Endpoint: Prevention of IFI
Posaconazole vs Flu/Itra
Cornely OA et al. N Engl J Med 2007;356:348-59.
Fluconazole n=304Posaconazole n=298
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 20 40 60 80 100
Pro
babi
lity
of D
eath
Days After Randomization
P = .04*
PosaconazoleFluconazole or Itraconazole
Death From Any Cause
*Estimated using log-rank statistics.Censoring time is the minimum of the last contact date and day 100.
Cornely OA, et al. N Engl J Med 2007;356:348-359
21%
14%
33% relative reduction in
mortality
Antifungal Prophylaxis: Neutropenia
N = 600Firstdose
Lastdose
Last dose+ 7 days
Posaconazole
(n = 301)
(n = 299)
Fluconazole
Secondary end point time periodPrimary end point time period
Day112
Day 112+2 months
Follow-up
Ullmann AJ et al. New Engl J Med. 2007;356:335-47.
Posaconazole vs Fluconazole
Antifungal Prophylaxis: GVHD
Study Design
* P=0.07; † P= 0.006; ‡ P=0.004; § P=0.001
Ullmann AJ et al. New Engl J Med. 2007;356:335-47.
Antifungal Prophylaxis: GVHD
†
Fixed Treatment Period Exposure Period
Num
ber o
f IFI
(Pro
ven/
Pro
babl
e)
‡ §
(5%) 16
7 (2%) (2%) 7
3 (1%)
27 (9%)
(7%) 21 22 (8%)
(6%) 17
0
5
10
15
20
25
30
35
40
All IFIs* Aspergillosis All IFIs Aspergillosis
Fluconazole n=304Posaconazole n=298
Primary Endpoint: Prevention of IFI
Deaths - By Cause
39
42 2
31
37
12 11
1
33
0
5
10
15
20
25
30
35
40
45
Adverse Event IFI - InfectionComplications
Proven or ProbableInfection
Possible Infection Progression ofUnderlying Disease
or GVHD
Fluconazole (N=301)Posaconazole (N=299)
**
*
Ullmann AJ et al. New Engl J Med. 2007;356:335-47.
Antifungal Prophylaxis: GVHD
*
Comparative Efficacy in ProphylaxisRetrospective review: 573 AML inductions over 12 years
Ananda-Rajah et al; Hematologica 2012;97(3)
De Pauw BE. N Engl J Med. 2007;356:409-11.
Prophylaxis:
What are the trade-offs in the long-term? Cost and potential resistance Incidence within an institution (number-needed-
to-treat)
ResistanceIntrinsic barrier to resistance for molds Infections acquired in the community Not transmitted person to person No selection pressure on the environmental
reservoir
Breakthroughs in 3 years of posaconazole prophylaxis
• Intrinsic resistance only 1 case of MDR Fusarium 1 case of Aspergillus calidoustus
Costs Costs
Prophylactic agent Benefits
Reduced empiric antifungal use or screening protocols
Reduction in associated costs (ICU stay, other drugs/fever workup)
Reduction in mortality Sensitive to NNT – linked to local epidemiology
FUNGAL PROPHYLAXIS
AML/MDS induction
Stem cell transplant GVHD
FLUCONAZOLE Allo transplant: 400 mg PO/IV QD
Autologous transplant: 200 mg IV/PO QD GVHD: 200-400 mg PO/IV QD
(adjust with renal function, check for interactions)
POSACONAZOLE 200 mg PO TID
(Check for interactions, optimize absorption**)
AML/MDS Induction
(this is the only indication for
posaconazole)
YES
NO **Absorption: Avoid acid suppressants; give with or after high
fat meal or with nutritional supplement
MUHC Algorithm – Prophylaxis
MUHC Algorithm – PreemptiveAutologous HSCT, Consolidation, Allo HSCT pre-engraftment