Mycology Flashcards
Substance in fungal cell wall
Chitin
Character of fungi: true nucleus, 80s ribosomes, mitochondria
Eukaryotic
Major membrane sterol of fungi
Ergosterol
Inhibit ergosterol synthesis
Imidazole antifungals
Bind more tightly to ergosterol than cholesterol
Polyene antifungals
Organisms living on dead organic material
Saprophytic or saprobic
Two basic forms of fungal structure
Yeast Mold
Basic forms of fungal structure exhibit this character
Thermal dimorphism
Two type of host response of fungal pathogens
Granulomatous response Pyogenic response
Fungal toxin in Amanita mushroom that causes liver necrosis
Amanitin Phylloidin
Ingestion of contaminated peanuts and grains causes liver cancer due to
Aflatoxin (Aspergillus flavus toxin)
Laboratory diagnosis of fungi that uses low pH to inhibit the growth of bacteria
Sabouraud’s agar
Infect only superficial keratinized structures Septate hyphae in 10% KOH Hyphae and conidia on Sabouraud’s agar Green fluorecence on Wood’s lamp
Dermatophytoses
Three important dermatophytes
Microsporum canis Trichophyton tonsurans Epidermophyton floccosum
Asteroid body Dimorphic fungi that lives on vegetation Occurs most often in gardeners via thorn prick
Sporotrichosis
Dimorphic fungus that exists as mold in soil and yeast in tissue/spherules Inhaled by arthrospores Treated with amphotericin B or itraconazole
Coccidioides immitis
Influenza-like illness Lung infiltrates, adenopathy, effusions Erythema nodosum Arthralgias Meningitis
Valley fever
Two great mimickers of PTB
Histoplasmosis Paragonimus
Two types of of asexual spores formed by Histoplasma capsulatum
Tuberculate macroconidia Microconidia
Round yeast with broad-base bud Transmitted by inhalation of conidia Most common cause of fungal pneumonia Ulcerated granulomas Lytic bone lesions Prostatitis
Blastomyces dermatitidis
Thick yeast with multiple buds in wheel configuration (mariner’s wheel) Transmitted via inhalation of conidia Chronic pneumonia with painful ulcers on mouth and nose
Paracoccidioides brasiliensis
Predisposing factors to opportunistic mycosis
Broad-spectrum antibiotic use Steroid use Hematologic malignancies Transplant recipients Systemic chemotherapy AIDS
Normal flora of URT, GIT, FGUT May appear as oval yeast with a single bud or as pseudohyphae Form germ tubes in serum and chlamydo-spores in culture
Candida Albicans
Presentation of Candida albicans in immunocompromised patients
Pseudomembranous esophagitis Subcutaneous nodules Right-sided endocarditis
Diagnostic tests that show the presence of Cryptococcus neoformans
Oval yeast with narrow-based bud surrounded by a wide polysacchtadise capsule seen in India ink preparation Positive latex agglutination test
Grows abundant in soil with bird droppings Transmission by inhalation of airborne yeast cell (Eucalyptus tree) Asymptomatic lung infection, meningitis, encephalitis
Cryptococcus neoformans
Exists as molds, with septate hyphae that form V-shaped dichotomous branches
Aspergillus fumigatus
Asthmatic symptoms with expectoration of brownish bronchial pulgs
Allergic bronchopulmonary aspergillosis
Saprophytic mold with non-septate hyphae with walls and branches at right angles Rhino-orbital-cerebral infectionnwith eschar formation Common in patients with DKA, burns, leukemia
Rhizopus oryzae / Mucormycosis
An indeterminate organism that is diagnosed by staining BAL washings Transmission is by inhalation of cysts Cysts in the alveoli induce an inflammatory response consisting plasma cells Seen in diffuse interstitial pneumonia with ground glass infiltrates bilaterally
Pneumocystis jiroveci
Major surface glycoproteinnof Pneumocystis jiroveci undergoes _____
Programmed rearrangements
Inciting organism of Tinea Versicolor Spaghetti and meatballs appearance on 10% KOH
Malassezia Furfur
