M1: Mycology Flashcards
10-100 fold larger. Eukaryotic MO. Contain a well defined nucleus as well as cytoplasmic organelles such as mitochondria, golgi & ER. Exhibit aerobic respiration. Slow growing with doubling times in terms of hours rather than minutes.
Fungi
The plasma cell membrane of the fungi contain _______ than cholesterol as the principal membrane sterol.
Ergosterol
Usually unicellular reproduce by budding or by fission and produce round pasty or mucoid colonies on agar.
Yeasts
Multicellular organisms consisting of threadlike tubular structures called ______. That elongate at their tips by process called __________.
Molds. Hyphae. Apical extension.
The hyphae combine to produce a matlike structure
Mycelium
The colonies formed by _______ are often described as filamentous, hairy and wooly.
Molds
The hyphae may also produce specialized asexual reproductive elements known as
Spore & Conidia
The form of fungus producing sexual spores is termed as
Teleomorph
Form producing asexual spores is termed as
Anamorph
Is isolated from clinical specimen
Anamorphic state
Occurs only under very specialized conditions in the laboratory
Teleomorphic phase
Capable of initiating infection in a normal, apparently immunocompromised host. Possess putative virulence factors that allow them to actively breach host defenses that ordinarily restrict the invasive growth of other microbes.
Primary pathogens
Only cause infection when there are disruptions in the protective barriers of the skin & mucous membranes or when defects in the host immune system to allow them to penetrate,colonize & reproduce the host.
Opportunistic pathogens
Characterized by filamentous septate hyphae typically found in soil or decaying vegetation and that produces the airborne infectious cells.
Saprobic phase
Adapted to grow at 37°c and to reproduce asexually in the alternative environmental niche of the host respiratory mucosa.
Parasitic phase
Most important line of defense against the endemic dimorphic fungi is the
Pulmonary macrophage
Both primary and opportunistic fungal pathogens are capable of replication at
37°C
Knowledge of the specific etiology agent may have important prognostic implications and may directly influence the choice of
Antifungal Therapy
The identification of _________ fungi to the species level often requires the determination of the biochemical and physiologic profile of the organism in addition to the assessment of the microscopic morphology.
Yeastlike
The definitive identification of a _____ is based almost entirely on its microscopic morphology.
Mold
The endemic dimorphic pathogens are identified by their microscopic features by the demonstration of __________ and by exoantigen and _______________.
Thermal dimorphism. Nucleic acid probe test.
Inhibit the 1,3 B-glucan synthesis enzyme complex, resulting in deficient cell wall production. Selective in its toxicity for fungi.
Echinocandin antifungal agents
Azole resistance in C. Albicans can be caused by overexpression or mutation of __________ and by overexpression of efflux plumps, CDR & MDR genes.
14-a-demethylase
May be able to achieve a better clinical outcome than with monotherapy
Combination therapy
May be achieved by combining two agents such as terbifanine and an azole that both attack the sterol pathway at different points, resulting in a more effective inhibition of ergosterol synthesis and disruption of the fungal cell membrane.
Synergy
