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52 Cards in this Set

  • Front
  • Back
The Fungi are members of what kingdom
Myceteae
What are the complex polysaccharides that made up the rigid cells walls of Fungi
Chitin, glucans, mannans
What are the four hereotrophic states of Fungi
Saprobes, Symbionts, Commensals, Parasites
What are saprobes
Organisms that live on dead or decaying matter
What are symbionts
Organisms that live together and in which the association is of mutual advantage
What are commensals
Organisms living in a close relationship in which one benefits from the relationship and the other neither benefits nor is harmed
What are parasites
Organsims that live on or within a host, from which they derive benefits without making useful contribution in return; in the case of pathogens the relationship is harmful to the host
How can yeasts be defined morphologically
A cell that reproduces by budding or by fission, in which a progenitor or "mother" cell pinches off a portion of itself to produce a progeny or "daughter" cell. The daughter cells may elongate to form sausagelike pseudoyphae. Yeasts are usually unicellular and produce round, pasty or mucoid colonies on agar
How can moulds be defined morphologically
Multicellular organisms consisting of threadlike tubular structures call hyphae that elongate at their tips by a process known as apical extension. Hyphae are either coencoytic or septate. The hyphae form together to produce a matlike structure called a mycelium. The colonies formed by moulds are often described as filamentous, hairy, or woolly
How do coenocytic hyphae look
Hollow and multinucleate
How do septate hyphae look
Divided by partitions or cross-walls
What is the name for the form of the fungus producing sexual spores
Teleomorph
What is the name for the fungus producing asexual spores
Anamorph
In what form are the fungi isolated from patient specimens
Anamorph, the asexual form
What are the two general types of asexual fungal spores
Sporangiospores and conidia
What are the characterisitcs of Zygomycetes
Moulds with broad, coenocytic hyphae, rare septa, asexual sporangiospores; hyphae with rhizoids
What are the characteristics of Ascomycetes
Yeasts and moulds, septate hyphae; conidiophores produce asexual spores; sexual spores produced in ascus
What are the characteristics of Deuteromycetes
Imperfect fungi; sexual stage unknown; septate hyphae, conidia produced on conidiophores; yeasts reproduce by budding
What organism produces the superficial disease Pityriasis versicolor
Malassezia furfur
What organisms produces Ringworm (tinea)
Trichophyton species
What two opportunistic fungal species produce Zygomycosis
Mucor and Rhizopus
Which fungi cause endemic mycoses
Histoplasma, Blastomyces, Coccidioides, Paracoccidioides, Penicilium marneffei
These are true virulent pathogens that can cause infection in healthy normal people.
Primary infection in the lung, then may disseminate
What fungi cause opportunistic mycoses
Aspergillus, Candida, Crytococcus neoformans, Pneumocystis jiroveci
These cause disease in immunocompromised individuals
How are fungal infections transmitted
Respiratory inhalation of spores
Systemic spread by normal flora (Candida) or dissemination from the lungs
Cutaneous/subcutaneous inoculation (sporothrix, dematiaceous molds)
Direct contact with infected hosts (dermatophytoses)
What is the primary protective host response to fungal pathogens
Cellular
What fungus can produce chronic, local dermal inflammation
Dermatophytes
What funus can produce allergic hypersensitivity without tissue invasion
Allergic bronchopulmonary aspergillosis
Infection with what fungus can lead to acute pyogenic abscess
Candida
Infection with what fungus can lead to chronic granuloma formation
Histoplasma (mimics TB)
Infection with what fungus can lead to mixed pyogenic/granulomatous inflammation
Blastomyces
Infection with what fungi can lead to blood vessel invasion with thrombosis and infarction
Mucor or Rhizopus
Aspergillus
India ink stains for what
Cryptococcus capsule
What does mucicarmine stain for
Cryptococcus neoformans capsule
What are the characteristics of Amphotericin B
Binds to ergosterol; increases membrane permeability resulting in leakage of cytoplasmic contents, also causes cascade of oxidative reactions which generate toxic free radicals; fungicidal, IV
What are the characteristics of azoles
Inhibit ergosterol synthesis (at the lanosterol C14 a-demethylase, cytochrome P-450-dependent, enzymatic step). The depletions of ergosterol disrupts the permeability of the fungal cell membrane
What are the three Triazoles
Fluconazole, Itraconazole, Voriconazole
What are the three Imidazoles
Ketoconazole, Clotrimazole, Miconazole
What type of infections are Clortimazole and Miconazole used for
They are too toxic for systemic use, so they are primarily used for topical fungal infections, includings pityriasis versicolor, cutaneous candidiasis, and the dermatophytosis (tinea pedis, corporis, etc.)
What is the drug of choice for chronic mucocutaneous candidiasis (Candida on every surface)
Ketonazole. It is not used for systemic candidiasis (Amphotericin B is)
What drug kills Candida albicans very well
Fluconazole, one of the Triazoles
Fluconazole is limited to what spectrum of fungi
Yeasts, Cryptococcus, dermatophytes
What is Itraconazole used for
First line treatment for chromoblastomycosis, histoplasmosis, coccidioidomycosis, blastomycosis, and possible for invasive aspergillosis
Voriconazole may be used with what
Invasive aspergillosis
How do the Echinocandins work
They inhibit synthesis of B-(1,3)-glucans, a component of cell walls of specific fungi
What is the Echinocandin drug Caspofungin (Cancidas) approved for
IV use vs. invasive infections by Candidia (fungicidal) and Aspergillus (fungistatic)
How does Flucytosine work
It interferes with synthesis of DNA, RNA. It is used as a tag team partner with Amphotericin B, since resistance develops if used alone
What does Flucytosine work against
It is Fungistatic and narrow spectrum against Candidia species and Cryptococcus
How do Allylamines work
They inhibit squalene epoxidase, blocking ergosterol synthesis at the squalene to lanosterol step; Fungistatic
What are the two Allylamine drugs
Terbinafine and Naftifine
How does Griseofulvin work
It disrupts microtubules, resulting in inhibition of fungal mitosis
What is Griseofulvin used against
Visualize griseofulvin as a greasy fulcrum used to lever the dermatophyte plaques off the skin. The worker is peeling fungus off your "toe," sis
Infection with what can lead to hypersensitivity without tissue reaction
Allergic bronchopulmonary aspergillosis