Medical and Pathogenic Mycology

1

• Medical and Pathogenic Mycology
• Fungal ABCs

2
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

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Invasive Mold Infections

• Immunosuppressed patients only
• Pulmonary infection by inhalation of airborne
  spores with subsequent dissemination
• Very aggressive, destructive
• Aspergillus most common (gt80)
• Aspergillus fumigatus most common species
• Others
• Rhizopus, Absidia, Mucor (Zygomycetes)
• Penicilllium
• Pseudallescheria boydii

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Aspergillus fumigatus

• Ubiquitous mold
• Found on decaying material
• Produces large amount of airborne conidia
• On average at 100 to 1000 conidia are inhaled
  daily

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Invasive Aspergillosis

• Risk Groups - Risk Factors

• 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

SOT solid organ transplant
Marr KA et al. Blood 20021004358-66 Lin SJ et
al. Clin Infect Dis. 200132358-66.
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Time to Onset of IFI After HSCT
of UFUs
PG Pappas Transplant Associated Infection
Surveillance Network
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Trends in Mortality

• Invasive Mycotic Diseases 1980 1997

Candidiasis
Other Mycoses 329
Rate per 100,000 population
Aspergillosis 357
Year
McNeil MM et al. Clin Infect Dis. 200133641-7.
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Invasive Aspergillosis in CanadaEmerging
Epidemiology
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The Diagnostic Challenge IA
Proven Histopathology and/or Growth in culture from tissue biopsy or aspirate from asterile 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
Ascioglu S et al. Clin Infect Dis. 2002347-14.
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Autopsy-Proven IFD ConfirmsUnder-Diagnosis of IFD

• Two-site autopsy study of 97 allogeneic stem cell
  recipients

IFI Deaths
Ante Mortem Screening (1) Regular galactomannan
testing (2) CT scans
Sinko et al. Transpl Infect Dis 2008 10 106 -109
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Diagnostic Methods
CT 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
Perlroth J et al. Med Mycol. 200745321-46.
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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

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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 gt 2 associated with a 4.68 CHR of death

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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).

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Case

• 51 year old woman
• April 2010 AML
• Induced with FLAG-IDA
• CR
• March 2011
• Allo HSCT from brother

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Case

• Several 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

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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

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4
Days
20
Days
21
Voriconazole
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McGill University Incidence of IA
AML and Allogeneic Stem Cell Transplant patients
Pre-galactoamman
Incidence of IA
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McGill University Incidence of IA
AML and Allogeneic Stem Cell Transplant patients
Post-galactomannan
Incidence of IA
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Rates of Invasive Aspergillosis
Centre Population IA Incidence ()
Maisonneuve Rosemont Hospital Allogeneic HSCT 15
Maisonneuve Rosemont Hospital Acute Leukemia 8.9
Vancouver General Hospital Allogeneic HSCT 18.8
Hotel Dieu Quebec AML 17.8
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Invasive Fungal Infection

• Management

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Antifungal Agents - Sites of Action
ß-1, 3 glucanpolysaccharide
Ergosterol
Cell Membrane Phospholipid bilayer
Adapted from Metcalf SC, Dockrell DH. J Infect.
200755287-99.
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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 approved ABLC Amphotericin B lipid
complex ABCD Amphotericin B colloidal
dispersion L-AMB Liposomal amphotericin B
Metcalf SC, Dockrell DH. J Infect
200755287-299 Petrikkos G, Skiada A. Internat
J Antimicrob Agents 200730108-117
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IFI Management
Prophylactic
Asymptomatic high-risk patient
Asymptomatic colonization OR novel diagnostic
Preemptive
Empirical
High risk Antibiotic fever
Evidence of infection clinical disease
Therapy
Wingard JR. Best Pract Res Clin Haematol
20072099-107 Bow EJ. Hematol. 20061361-7.
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IA Primary Therapy
Voriconazole vs. Amphotericin B
Survival at 12 weeks
70.8
Patients Surviving ()
57.9
P0.02
Weeks
No. at Risk Voriconazole 144 131 125 117 111 107
102 Amphotericin B 133 117 99 87 84 80 77
Herbrecht R et al. N Engl J Med. 2002347408-15.
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Voriconazole

• Caveats
• No activity against Zygomycetes
• Erratic pharmacokinetics
• Drug interactions
• Hepatotoxicity
• Visual toxicity

Cumulative Incidence ()
Siwek GT et al. Clin Infect Dis. 200439584-7
Scott LJ, Simpson D. Drugs 200767269-298
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IA Salvage Therapy

• Caspofungin
• 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

Maertens J et al. Clin Infect Dis.
2004391563-71.
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Early Intervention is Associated with Lower
Mortality
Retrospective analysis of the timing of empiric
antifungal treatment for 33 cases of invasive
aspergillosis between 1987 and 1992
Von Eiff et al. Respiration. 199562341-347.
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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

Morrell M et al. Antimicrob Agents Chemother.
2005493640-5.
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IFI Management
Prophylactic
Asymptomatic high-risk patient
Asymptomatic colonization OR novel diagnostic
Preemptive
Empirical
High risk Antibiotic fever
Evidence of infection clinical disease
Therapy
Bow EJ. Hematol. 20061361-7.
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Empirical Therapy

• Treat all neutropenic patients with persistent
  fever despite broad-spectrum antibiotics

• 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

Wingard JR. Best Pract Res Clin Haematol
20072099-107 Bow EJ. Hematol 20061361-367
Pizzo Am J Med. 198272101-11 EORTC Am J Med.
198986668-72.
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Early Trials

• Pizzo Am J Med 1982
• First comparative evaluation of empiric
  antifungal therapy
• Enrollment Criteria
• Fever for 7d after antimicrobials started,
  PMNlt500
• Predominately pediatric population (mean age 16)
• Randomized to stopping all abts, no change or
  0.5mg/kg/d AmB

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Pizzo - Outcomes
No ? 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
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EORTC Trial

• Larger study of empiric AmB use in febrile
  neutropenics
• Enrollment
• Adult population
• Fever for 4 days after antibacterials started
• PMNlt1000
• Randomized to empiric AmB 0.6mg/kg/d or
  1.2mg/kg/2d

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EORTC - Outcomes
No ? AmB
pts 64 68
Candida 4 1
Mold 2 0
Survival 79 84
Response (fever) 53 69
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Empirical Therapy
Voriconazole or Caspofungin vs L-AMB
VOR N415 L-AMB N422 Point Estimate for Percent Difference (95 CI)
Overall response no. () 108 (26) 129 (30.6) -4.5 (-10.6 to 1.6) PNS
Breakthrough fungal infection 8 (1.9) 21 (5.0) P0.02
CAS N556 L-AMB N539 Point Estimate for Percent Difference (95 CI)
Overall response no. () 190 (33.9) 181 (33.7) 0.2 (-5.6 to 6.0) Non-inferiority
Absence of breakthrough fungal infection 29 (5.2) 24 (4.5) P0.56
Walsh T et al. N Engl J Med. 2002346225-35 N
Engl J Med. 20043511391-1402.
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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?

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IFI Management
Prophylactic
Asymptomatic high-risk patient
Asymptomatic colonization OR novel diagnostic
Preemptive
Empirical
High risk Antibiotic fever
Evidence of infection clinical disease
Therapy
Bow EJ. Hematol. 20061361-7.
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Preemptive Therapy
Incorporation of Diagnostic Tests
High-risk hematology patients (all received
Candida prophylaxis, fluconazole 400 mg/day)
Daily GM monitoring and clinical evaluation
gt5 days of unexplained neutropenic
feverrefractory toantibiotics or relapsing
New infiltrate on chest X-ray or signs/symptoms
of invasive mycosis
Positive culture or microscopy (molds)
OD index 2 x 0.5
Thoracic CT scan ( CT sinus)
Thoracic CT BAL
Characteristic of invasivemycosis halo-sign
Atypical lesion
Normal
Bronchoscopy with BAL
-

Broad-spectrumantifungal therapy
Continued monitoring No antifungal therapy
Maertens J et al. Clin Infect Dis.
2005411242-50.
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Empirical vs Preemptive antifungal therapy in
high risk neutropenic patients
Overall survival
Proven and probable IFI
pns
plt0.02
Cordonnier et al. CID 2009
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Preemptive Therapy Does Not Reduce IA Mortality
46

• If earlier is better
• Is prevention best?

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IFI Management
Prophylactic
Asymptomatic high-risk patient
Asymptomatic colonization OR novel diagnostic
Preemptive
Empirical
High risk Antibiotic fever
Evidence of infection clinical disease
Therapy
Bow EJ. Hematol. 20061361-7.
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Fluconazole Prophylaxis in HSCT

• Evidence for Long-term Survival

Related and Unrelated Donor Transplants
Fluconazole 400 mg/d
Survival Probability
P .0018
Placebo
Years After Transplant
HSCT indicates hematopoietic stem cell transplant.
Marr KA, et al. Blood. 2000962055-2061.
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Overall Treatment Success

• Micafungin vs. Fluconazole

Proportion of patients with treatment success
P 0.025, by the log rank test
micafungin (n 425) Fluconazole (n 457)
Time to treatment failure (days since first dose
of study drug)
Adapted from van Burik JA, et al Clin Infect Dis
2004 39(10)1407-16.
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Voriconazole vs. Fluconazole
p0.49
p0.12
Subjects 600 standard-risk allogeneic blood and
marrow transplant patients
Proven probable presumptive Adapted from
Wingard JR, et al Blood epub 2010
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Voriconazole vs. Itraconazole Improvit
489 allogeneic stem cell transplant patients
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Antifungal Prophylaxis Neutropenia
Posaconazole vs Fluconazole / Itraconazole
Study Design
Posaconazole (n 304)
Chemotherapy prophylaxis
Chemotherapy prophylaxis (if needed)
Day 100postrandomization
N 602
Fluconazole or Itraconazole (n 298)
Primary end point time period
Secondary end point time period
Cornely OA et al. N Engl J Med 2007356348-59.
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Posaconazole vs Flu/Itra
Primary Endpoint Prevention of IFI
Treatment Phase
100 Day Period After Randomization

Plt0.001 P 0.003
Cornely OA et al. N Engl J Med 2007356348-59.
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Antifungal Prophylaxis Neutropenia
Death From Any Cause
Posaconazole Fluconazole or Itraconazole
21
P .04
Probability of Death
14
33 relative reduction in mortality
Days After Randomization
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 2007356348-359
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Antifungal Prophylaxis GVHD
Posaconazole vs Fluconazole
Study Design
Posaconazole (n 301)
N 600
Firstdose
Lastdose
Last dose 7 days
Day112
Day 1122 months
(n 299) Fluconazole
Secondary end point time period
Primary end point time period
Follow-up
Ullmann AJ et al. New Engl J Med. 2007356335-47.
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Antifungal Prophylaxis GVHD
Primary Endpoint Prevention of IFI
Fixed Treatment Period
Exposure Period
Number of IFI (Proven/Probable)



P0.07 P 0.006 P0.004 P0.001
Ullmann AJ et al. New Engl J Med. 2007356335-47.
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Antifungal Prophylaxis GVHD
Deaths - By Cause



Ullmann AJ et al. New Engl J Med. 2007356335-47.
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Comparative Efficacy in Prophylaxis
Retrospective review 573 AML inductions over 12
years
Ananda-Rajah et al Hematologica 201297(3)
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Prophylaxis

• What are the trade-offs in the long-term?
• Cost and potential resistance
• Incidence within an institution
  (number-needed-to-treat)

De Pauw BE. N Engl J Med. 2007356409-11.
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Resistance

• Intrinsic 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

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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

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MUHC Algorithm Prophylaxis
FUNGAL PROPHYLAXIS AML/MDS induction Stem cell
transplant GVHD
POSACONAZOLE 200 mg PO TID (Check for
interactions, optimize absorption)
AML/MDS Induction (this is the only indication
for posaconazole)
YES
Absorption Avoid acid suppressants give with
or after high fat meal or with nutritional
supplement
NO
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)
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MUHC Algorithm Preemptive
Autologous HSCT, Consolidation, Allo HSCT
pre-engraftment