Lab Final Flashcards
What characteristics make fungi true pathogens?
-have ability to attack and invade tissues
-exhibit dimorphism (can be mold/spores and yeast)
Based on temperature:
Mold in environment <30°C
Yeast in body >30°C
-yeasts are invasive
Production of enzymes and proteins
-endemic to certain regions, primarily the americas
Opportunistic fungi characteristics
-usually 2° infections
-take advantage of a weakness in a hosts defenses
-distributed throughout the world
-dermatophytes are considered opportunists
Factors that predispose individuals to opportunistic mycoses?
-medical procedures (surgery)
-medical therapies (cancer, steroid treatments)
-preexisting conditions (aids, diabetes)
-lifestyle factors (poor diet, hygiene or drugs)
3 clinical categories of fungal diseases?
-fungal infections *most common
Regular infection (skin) true or opportunist pathogen
-toxicoses *aquired through ingestion
Fungal toxins contaminate other foods
(Mycetusmus-intoxication from eating poison mushroom)
-allergies *inhalation of fungal spores
What is critical for diagnosis of most mycoses?
Pt history :
Hobbies?
Travel?
What been doing lately ?
Fungal infection diagnosis require?
Isolation, lab culture, and morphological analysis of fungus
*2 weeks to grow
Best medium to grow fungi?
Medium full of carbohydrate and ph of 5
(This medium favors fungal growth over bacterial growth)
Immunological test are useful for fungi?
T/F?
Why?
False
Due to prevelance of fungi in environment, it is hard to distinguish between infection and simple exposure.
Opportunistic fungal infections are __________ to diagnose
Why?
Difficult
Fungal types can be confused with one another as well as with other diseases
Fungi can display abnormal morphology in tissues where infection wouldn’t normally occur.
Why is mycoses among the most difficult diseases to heal ?
- fungi can often resist oxidative damage of T cells during cell-mediated immune response
-as eukaryotes, fungi are similar to human cells and anti fungal drugs can harm human tissues
Fungi has (ergosterol/cholesterol) in their membranes and it is often a target of __________ treatment
Ergosterol
Antifungal
What is the “gold standard” of antifungal agents but also the most toxic?
Amphoterecin B
What are other antifungal agents ?
-azole drugs
-fluorocytosine
-griseofulvin
Opportunistic require what 2 steps?
High dose treatment to eliminate/reduce fungal pathogen
Long term maintenance therapy to control/prevent infection
Topical antifungal ?
Imidazole
