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Micro 04 - Opportunistic Mycoses


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5 main opportunistic Fungi
Pneumocystis Carinii
Penicillium marneffeii
Are opportunistic fungi inherently pathogenic?
-one of the most common __1__ infections
-frequency has risen __2__ since 1980
-nosocomial candidiasis is associated with excess __3__
1. nosocomial
2. five-fold
3. mortality (>40%)
Describe Nosocomial Candidiasis
People walk into the hospital with C. albicans and walk out with C. tropicalis, a more drug-resistant species
80% of people have Candida in ______ surfaces
Where is Candida rarely found?
List several factors for Candidiasis
Broad-spectrum antibiotics
BMT or Solid organ transplants
Perianal Cutaneous Candidiasis is associated with _________
Antibiotic use
Does Mucocutaneous candidiasis have propensity to progress to disseminated disease?
Why is Candida Vulvovaginitis not always considered Opportunistic?
b/c it occurs in healthy women
What are some promoting factors of Candida Vulvovaginitis?
1. Specific sexual behaviors
2. Antibiotic use
3. higher pH
4. Diabetics
Eye condition Candida can cause

Hematogenous Endophthalmitis
-can cause blindness
All patients with Candidemia should have this exam
Dilated Retinal Exam to check for Hematogenous Endophthalmitis
-see colonies with filamentous border
Candidemia symptoms
-renal shutdown?
Possible causes of Candidemia
Urinary candidiasis is associated with?
Catheter use
-candida in urine is not always significant though
DOC for Hematogenous Endophthalmitis
Fluconazole b/c it can penetrate into the eye
Invasive Candidiasis usually only occurs in these people
Species most often involved in Invasive Candidiasis (2)
C. albicans
C. tropicalis

*C. glabrata is increasing
HIV patients usually present with Candidia infections of __1__ and __2__
1. oropharynx
2. GI tract

*rarely systemic disease
*not a defining disease for AIDS
Organs involved in Invasive Candidiasis

Diagnosis of Candidiasis

Yeasts with Pseudohyphae
How are Candida SPECIES diagnosed?
Metabolic tests
Morph structures
Treatment for Disseminated Candidiasis
1. IV Amphotericin B +/- Flucytosine

2. predisposing conditions should be controlled
-diabetes, neutropenia, malnutrition
What is C. glabrata resistant to?
Topical treatment sometimes used for Candida Vulvovaginitis
Boric Acid
Candida Endocarditis usually requires this treatment
Valve replacement

Long-term therapy with Fluconazole
Neonatal treatment for Candidiasis
Amphotericin B
Urinary Candidiasis treatment
Fluconazole or AmB
Endophthalmitis treatment
AmB +/- Flucytosine
Fluconazole (penetrates into eyes)
Practical uses of Aspergillus
food production
3 diseases of Aspergillus
1. Allergic Bronchopulmonary Aspergillosis
2. Pulmonary Aspergilloma
3. Invasive Aspergillosis
Hypersensitivity disease in Allergic Bronchopulmonary Aspergillosis is almost always caused by ___________ (species?)
A. fumigatus
Allergic Bronchopulmonary Aspergillosis is not uncommon in ___________
Cortico-steroid dependent Asthmatics
Where is Aspergillus commonly found?
Compost heaps (>40'C)
How is Aspergillus infection acquired?
Breathing spores

Direct invasion at sites of broken skin
Susceptibility factors for Invasive Aspergillosis
1. Neutropenia
2. Corticosteroid use
3. broad-spectrum antibiotics
Most common sites for Aspergillus disease
LUNGS (most common)
blood vessels
How does Aspergillus usually spread?
grows along or through tissue

usually not by fragmentation
Prognostic factors for Pulmonary Aspergilloma
1. # of lesions
2. severity of underlying disease
3. immunosuppression
4. HIV status
5. anti-Aspergillus IgG titer
Pulmonary Aspergilloma secondary symptoms
7% of these patients have Allergic Bronchopulmonary Aspergillosis
Cystic Fibrosis
Treatment of Allergic Bronchopulmonary Aspergillosis
Corticosteroids to lessen IgE response
What is the ultimate pathology of Invasive Aspergillosis?
penetrate the bloodstream and occlude vessels
Why is Aspergillosis especially difficult to diagnose? (3)
-blood cultures are usually negative
-positive sputum cultures may represent ENVIRONMENTAL CONTAMINATION
-pulmonary lesions can mimic TB or neoplasm
What observation is diagnostic of Aspergillosis?
movable Fungus ball within a cavitary lesion
Describe an Aspergillus biopsy specimen
Narrow, ACUTE branching septate hyphae
Mortality rate for untreated invasive aspergillosis
near 100%
Treatment for Invasive Aspergilosis
Amphotericin B
Aspergilloma treatment options
Surgical removal

Administer antifungal directly into lung via catheter
Unique characteristic of Zygomycetes
have Zygote as their reproductive structure
Where are Zygomycetes found?
they are Saphrophytic (live on dead organic matter) Soil fungi
3 Common Zygomycete fungi
Rhizopus arrhizus
Disease caused by Zygomycetes
Rhinocerebral Zygomycosis
-epistaxis (nose bleed)
-paranasal swelling
-necrotic tissues
Patients that are susceptible to Rhinocerebral Zygomycosis
Diabetic ketoacidosis


High-dose Corticosteroid
List 4 Secondary forms of Zygomycosis
1. primary cutaneous, pulmonary, or GI lesions
2. Hematogenous dissemination
3. invasion --> blood clots
4. can occur under occlusive dressings in burn patients
How do you diagnose Zygomycosis?

History with predisposing factors = diabetic, etc

Repeated culture from sterile site

Nonseptate Hyphae with Right angle branching
Explain the treatment method for Zygomycosis
Treatment may precede demonstration of the organism b/c Rhinocerebral Zygomycosis can be lethal within very few days
-Amphotericin B and Posaconazole
-Surgical debridement
-correct susceptibility
Pneumocystis carinii was once considered this type of organism

*ribotyping now says its fungus
3 morphologic stages of Pneumocystis
1. Trophozoite = multiplies by binary fision

2. Cyst = mature cysts contain 6-8 intracystic bodies

3. Pre-cystic = intermediate b/w trophs and cysts
Descrbie characteristics of Pneumocystis
1. found in the lungs of healthy humans and animals
2. NO enviromental reservoir identified
3. most children have been exposed by AGE 4
Pneumocystis is common in HIV+ patients with this CD4 count
< 200
PCP symptoms
Bilateral pneumonia
Non-productive cough
Diagnosis of Pneumocystis

Silver stained cysts in sputum, BAL, or lung biopsy
Treatment for PCP

Illness caused by Penicillium marneffei
flu-like pneumonia
How was Penicillium marneffei discovered?
from a Bamboo Rat in 1956
Explain the life cycle of Penicillium marneffei
grows as yeast at 37'C = thermally dimorphic

*only thermal dimorphic penicillium species
Where is Penicilliosis reported
among HIV patients in Asian countries
CD4 cell count of those infected with Penicillium marneffei
50 cells or less
How is Penicilliosis diagnosed?

-skin lesions appearing as papules with central necrosis
-fever, weight loss
-microscopic examination of bone marrow, skin
-culture for dimorphic fungi
Penicilliosis skin manifestation is similar to.....

Molluscum contagiosum
Treatment for Penicilliosis
AmB or Itraconazole

-Azole prophylaxis for life after initial treatment
Opportunistic fungi that occur in neutropenic patients (2)
Trichosporon beigelii

Blastoschizomyces capitatus
Fungus that causes UTI's and Pneumonia and is resistant to Azoles and AmB
Candida glabrata
2 commensal flora that can cause opportunistic infections

A soil fungus that is a plant pathogen

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