Fungi - Opportunistic Fungi Flashcards
Aspergillus fumigatus
lab tests
Asparagus Farm
Catalase (+) *
Acute branching (< 45º) with septations (Aspergillus)
(ddx Mucor which has 90º branching and is nonseptate)
* Candida also catalase (+). Catalase (+) ↑ risk of Chronic Granulomatous Disease (CGD)
Aspergillus fumigatus
source
Asparagus Farm
Aspergillus fumigatus is found nearly everywhere in soil and decaying plants (like compost heaps), and generally won’t infect healthy people.
They are condiospores with fruiting bodies that get inhaled by human.
Aspergillus fumigatus
3 types of infection
Asparagus Farm
- Allergic bronchopulmonary aspergillus (ABPA)
- Aspergillosis causing aspergillomas
- Angioinvasive aspergillosis
Aspergillus fumigatus
3 types of infection
1. Allergic bronchopulmonary aspergillus (ABPA)
Asparagus Farm
Causes asthma, wheezing, fever, and a migratory pulmonary infiltrate.
Type 1 hypersensitivity, IgE response.
Aspergillus fumigatus
3 types of infection
2. Aspergillosis causing aspergillomas
Asparagus Farm
Associated with TB (susceptibility ↑ with TB cavities)
Aspergillomas are gravity dependent so fungus balls will be at the bottom of the cavity
Aspergillus fumigatus
3 types of infection
3. Angioinvasive aspergillosis
Asparagus Farm
Seen in pt with neutropenia from leukemia or lymphoma.
Aspergillus invades blood vessels and the surrounding tissues.
Leads to kidney failure, endocarditis, ring enhancing lesions in the brain.
Invades nasal sinus (causing Angioinvasive aspergillosis) leading to hemoptysis (coughing up blood) or blood stained mucos.
Aspergillus flavus
Aspergillus flavus key facts
(NOT Aspergillus fumigatus!)
Asparagus Farm
Aflatoxin associated with peanuts or grain!
Can lead to Hepatocellular carcinoma (HCC)
Aspergillus fumigatus
treatment
Asparagus Farm
_For less serious infection_s: Voriconazole
For angioinvasive disease: AMP B
Candida albicans
lab tests
Candid Canadians
Dimorphic (but not mold in cold!!!)
- Budding yeast at 20º with pseudohyphae.
- Mold form with true hyphae germ tubes at 37º
catalase (+)*
AIDS defining illness at CD4 < 100
White patches in mouth can be scraped off for KOH prep. (vs. leukoplakia where patches CANT be scraped off)
* Aspergillus also catalase (+). Catalase (+) ↑ risk of Chronic Granulomatous Disease (CGD).
Candida albicans
source
Candid Canadians
Normal flora of the GI tract and Oral cavity.
Commonly contaminates sputum cultures.
Candida albicans
signs and symptoms
Candid Canadians
- Severe diaper rash (when exposed to heat and humidity)
- Oral candidiasis (in immunocompromised or from inhaled steroids)
- White patches in mouth (CAN be scraped for KOH prep)
- Esophagitis and white pseudo membranes
- Vaginal candidiasis
- Endocarditis
Candida albicans
AIDS defining illness
Candid Canadians
AIDS defining illness at CD4 < 100
Candida albicans
predisposing factors
Candid Canadians
- AIDS (CD4 < 100)
- Diabetics
- Birth control pills
- Antibiotics (due to lowering the pH).
* Candida infections occur at a pH < 4 vs. gardenella at a pH > 4.5
- IV drug users (Candida found in some heroine) infecting tricuspid valve.
Candida albicans
Treatment
Candid Canadians
For minor infections: Azoles
For major infections: AMP B
For oral or esophageal candiasis: Nystatin
For resistant candida: Capsofungin
Cryptococcus neoformans
lab tests
Crypt for Cryptococcus
- Cryptococci are heavily encapsulated.
- Repeating polysaccharide antigen. Can be detected by Latex agglutination test by causing agglutination.
- Urease (+)
- Bronchopulmonary washings of lung tissue that resembles soap bubbles. (can be stained with mucicarmine red or methanamine silver stains).
- Lumbar puncture and India ink will show wide encapsulated halos (Negative stain! Dark background with transparent organisms)
Cryptococcus neoformans
source
Crypt for Cryptococcus
Transmitted by pigeon droppings!
Also found in soil.
Inhaled into lungs.
Cryptococcus neoformans
signs and symptoms
Crypt for Cryptococcus
- Opportunistic infection. HIV, High dose steroids, Malignancies.
- Pulmonary symptoms like cough, dyspnea, pneumonia and other lung infections.
- Can spread to the CSF and cause meningitis, often leading to permanent neuro deficits.
- Fever
- Distinct pathology of brain having soap bubble lesions.
Cryptococcus neoformans
Treatment
Crypt for Cryptococcus
Joint therapy with AMP B and flucytosine…
Then fluconazole after
Mucormycoses
lab tests
Mu Car Auto Shop
Biopsy is needed for diagnosis.
Hyphae have right angle branching (90º) and are non-septate
(ddx Aspergillus which have acute branching < 45º and have septations “Aspergillus”)
Broad, irregular, and ribbon-like.
Mucormycoses
source
Mu Car Auto Shop
Mucormycoses is found nearly everywhere in soil and decaying plants (like compost heaps), and generally won’t infect healthy people.
Transmitted via spore inhalation.
Mucormycoses
signs and symptoms
Mu Car Auto Shop
Invade through cribriform plate in the skull → cause necrosis of tissues and frontal cortex abscesses.
- Presents as a black eschar and necrosis of nasal cavity and eyes, causing neuro deficits and death (Rhinocerebral mucormycosis)
Mucormycoses
predisposing factors
Mu Car Auto Shop
- Immunocompromised (leukemia, neutropenia, etc)
- Diabetes patients
- Diabetic Ketone acidosis (DKA) is the most common predisposing factor.
(Mucormycoses likes to proliferate in blood vessel walls, especially where there is ↑ glucose and ↑ keytones)
Mucormycoses
Rhizopus
Mu Car Auto Shop
Most common cause of Mucormycosis.
Rhizopus is a bread mold.
Mucormycoses
Treatment
Mu Car Auto Shop
- Debridement first: Surgically remove dead tissue.
- AMP B
Pneumocystis jiroveci (Pneumocystis Pneumonia)
lab tests
PCP Ping Pong
Bronchoalveolar lavage (BAL) for diagnosis.
Will often not be visible on XRAY, but if it is, it will have a cracked glass appearance in both lungs.
Methamine silver stain to identify fungus. Looks like disc shaped yeasts.
Pneumocystis jiroveci (Pneumocystis Pneumonia)
predisposing factors
PCP Ping Pong
- Associated with AIDS CD4 < 200
- Premature infants
- Immunocompromised
Pneumocystis jiroveci (Pneumocystis Pneumonia)
signs and symptoms
PCP Ping Pong
- PCP is a diffuse interstitial pneumonia
- pneumonia-like symptoms
- NON-productive cough
(symptoms evident in immunocompromised vs. asymptomatic in healthy individuals.)
Pneumocystis jiroveci (Pneumocystis Pneumonia)
Treatment
PCP Ping Pong
- Prophylaxis begins when CD4 count is < 200:
Bactrim (TMP/SMX) (Trimethoprim and sulfamethoxazole)
- If sulfa allergies:
Pentadamine
