Micro 04 - Opportunistic Mycoses
Terms
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- 5 main opportunistic Fungi
-
Candida
Aspergillus
Zygomycetes
Pneumocystis Carinii
Penicillium marneffeii - Are opportunistic fungi inherently pathogenic?
- No
-
Candidiasis:
-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
-
Mucosal
-GI
-GU - Where is Candida rarely found?
- Skin
- List several factors for Candidiasis
-
Chemotherapy
Broad-spectrum antibiotics
Catheters
BMT or Solid organ transplants - Perianal Cutaneous Candidiasis is associated with _________
- Antibiotic use
- Does Mucocutaneous candidiasis have propensity to progress to disseminated disease?
- no
- 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
-
Fever
-shock?
-oligouria?
-renal shutdown?
-DIC? - Possible causes of Candidemia
-
catheters
gut
nosocomial - 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
- Immunosuppressed
- 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
-
Any - 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?
- Fluconazole
- 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
or
Fluconazole (penetrates into eyes) - Practical uses of Aspergillus
-
research
industry
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)
Insulation
Dust - 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)
sinus
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
-
Fever
Hemoptysis - 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
Mucor
Absidia - Disease caused by Zygomycetes
-
Rhinocerebral Zygomycosis
-epistaxis (nose bleed)
-headache
-paranasal swelling
-necrotic tissues - Patients that are susceptible to Rhinocerebral Zygomycosis
-
Diabetic ketoacidosis
Neutropenia
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
-
Protozoa
*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
Dyspnea
Non-productive cough
fever - Diagnosis of Pneumocystis
-
Silver stained cysts in sputum, BAL, or lung biopsy - Treatment for PCP
-
Trimethoprim-Sulfamethoxazole
Pentamidine - 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
-
Candida
Malessezia - A soil fungus that is a plant pathogen
- Fusarium