Fungal Pathogens Flashcards
Name three risk factors for acquiring Candida albicans.
- HIV/Immunodeficiency.
- Prolonged Neutropenia.
- Steroid Treatment.
- Extreme Prematurity.
- Neutrophil Deficits.
- Lengthy Antibiotic Course.
- Indwelling Lines.
- GI Operation.
What are the possible clinical presentations of Candida albicans in an immunocompetent patient?
Oral thrush, vaginitis, and diaper rash.
What is the clinical presentation of Candida albicans in immunocompromised patients?
Oral thrush, esophageal candidiasis, endocarditis, endophthalmitis (inflammation of the inner coats of the eye), hepatosplenic candidiasis . . .
What is Candida albicans?
A yeast. It is found in some, but not all, people endogenously.
What would the treatment for Candida albicans be?
- Remove any indwelling lines.
- Fluconazole for stable patients.
- Amphotericin B for more serious cases.
What three fungi are associated with ringworm?
Trichophyton, Epidermophyton, and Microsporum.
What tropism is present with Trichophyton, Epidermophyton, and Microsporum?
A tropism for keratin.
Tinea (aka ringworm) has a centrifugal growth pattern. Where should samples for microscopy be taken from?
The outer ring of the growth. This is where the viable mould is growing.
Name three dermatophytes.
Trichophyton, Epidermophyton, and Microsporum.
Which fungi requires a high triglyceride content it grow? How is this yeast often contracted?
Malassezia
Often acquired through indwelling lines.
Malassezia is a yeast which causes which condition?
Tinea versicolor - lesions with different skin pigmentation.
Name four dimorphic fungi. In which form do these dimorphs exist in the human body?
Sporothrix schenckii, Coccidioidomycosis, Histoplasmosis, and Blastomycosis.
The yeast form predominates in the higher temperatures found in the human body.
Where are you likely to acquire Sporothrix schenckii from?
It is a soil saprophyte.
How does Sporothrix schenckii present?
Deep ulcerated lesions which progress up lymph vessels.
How and where does a person catch Coccidioidomycosis from?
The arthroconidia from the mould can become airborne and inhaled. Coccidioidomycosis like hot summers and are found in Arizona.
What are the symptoms of Coccidioidomycosis?
- Most people are asymptomatic.
- 40% get flu like symptoms.
- A small percentage gets pneumonia.
How is Coccidioidomycosis treated?
Fluconazole is most cases but Amphotericin B is used in severe cases.
Which fungal infection must be treated to avoid the death of the patient?
Histoplasmosis
What is one of the best forms of transmission for histoplasmosis?
Bat guano and bird excrement. It is endemic to Mississippi/Ohio river valleys, Australia, SE Asia, and South America.
How is histoplasmosis infection diagnosed?
Hilar Adenopathy, Culture, Fungal stain, Serological tests.
How is histoplasmosis treated?
Start with Amphotericin B and eventually transition to Itraconazole. 100% mortality without treatment of disseminated disease.
Briefly describe the pathogenesis of histoplasmosis infection.
Microconidia are inhaled and causes pneumonitis.
The microconidia are engulfed by neutrophils and conversion to yeast form takes place. The yeast then migrates to lymph nodes where it grows in macrophages.
Where is blastomycosis endemic?
North America - Mississippi/Ohio river valleys, Midwest states, Eastern Manitoba, and Ontario near the great lakes.
What are some of the symptoms of blastomycosis infection?
Fever, fatigue, and weight loss.
Chronic pneumonia, lobar consolidation on X-Ray.
Cutaneous lesions may be seen ate late stage infection.
Which fungi is hinted at if pets are also infected?
Blastomycosis
