Term
| What are the important constituents of fungal cell walls? |
|
Definition
| Glucans, chitin, and mannan. 9-3 |
|
|
Term
| What are the important constituents of fungal cell membranes? |
|
Definition
| Ergosterol (predominates) and zymosterol. 9-2 |
|
|
Term
| T/F. Fungi's motility varies by species and in dimorphic fungi it may vary depending upon the environment in which the organism is found. |
|
Definition
| False. Fungi are nonmotile. Spread by wind, water, and contact 9-2 |
|
|
Term
| What's the gram stain for fungi? |
|
Definition
| Don't Gram stain, except Candida. 9-2 |
|
|
Term
| Name the stains that will stain fungi in general. |
|
Definition
| Calcofluor. Silver stains. Periodic-acid schiff (PAS) 9-2 |
|
|
Term
| What molecule is most abundant in chitin? |
|
Definition
| N-acetylglucosamine. (NAG) 9-2 |
|
|
Term
| Is the following a characteristic of yeast or mold: pseudohyphae? |
|
Definition
|
|
Term
| Is the following a characteristic of yeast or mold: Include Cryptococcus neoformans? |
|
Definition
|
|
Term
| Is the following a characteristic of yeast or mold: produce multicellular forms? |
|
Definition
|
|
Term
| Is the following a characteristic of yeast or mold: have fuzzy colonies? |
|
Definition
|
|
Term
| Is the following a characteristic of yeast or mold: reproduce by budding? |
|
Definition
|
|
Term
| Is the following a characteristic of yeast or mold: are speciated by biochemical tests? |
|
Definition
|
|
Term
| Is the following a characteristic of yeast or mold: are speciated by colony morphology, color, and microscopic appearance? |
|
Definition
|
|
Term
| Is the following a characteristic of yeast or mold: reproduce by branching and longitudinal expansion. |
|
Definition
|
|
Term
| Name the four types of antifungals. |
|
Definition
| Amphotericin, azoles, echinocandins, and flucytosine. 9-4 |
|
|
Term
| Which drug binds to ergosterol and causes membrane permeability to increase? (like penicillin to fungi). |
|
Definition
|
|
Term
| What is the major toxicity of amphotericin? |
|
Definition
|
|
Term
| What is the target for azole drugs? |
|
Definition
| They bind to one of the cytochrome P-450 enzymes and inhibit the c-14 alpha demethylation of lanosterol. Lanosterol is a precursor for ergosterol. This leads to less ergosterol and increased methylsterols in the membrane. 9-4 |
|
|
Term
|
Definition
| Imidazole, Triazole, Fluconazole, Voriconazole, Itraconazole, and posaconazole. 9-4 |
|
|
Term
| What do echinocanidins inhibit? |
|
Definition
| Synthesis of 1,3-beta-D-glucan. It is against the cell wall synthesis. 9-4 |
|
|
Term
| Which agents target the 1,3-beta-D-glucan? |
|
Definition
|
|
Term
| Name the 3 enchinocandins. |
|
Definition
| Caspofungin, micafungin, and anidulafungin. 9-4 |
|
|
Term
| What are the most common side affects of echinocandins? |
|
Definition
| Headache and elevation of liver enzymes. 9-4 |
|
|
Term
| How does the antifungal drug flucytosine work? |
|
Definition
| interferes with fungal DNA synth, via Noncompetitive inhibition of thymidylate synthase. It is a fluorine analogue of cytosine. 9-4 |
|
|
Term
| What is the most common use of flucytosine? |
|
Definition
Used with amphotericin against cryptococcal meningitis. Use as a monotherapy rapidly induces resistance.
9-4 |
|
|
Term
| Name risk factors for candidal infection. |
|
Definition
Antibiotics that destroy flora of GI or vagina. Steroid and anti-metabolites that impair cell mediated immunity or induce neutropenia. Chemotherapeutic agents that cause mucosal injury and ulceration of GI tract. GI surgery (b/c it leads to spillage of GI organisms into peritoneal cavity)
. 9-5 |
|
|
Term
| Which organism is identified by india ink stain? |
|
Definition
| Cryptococcus neoformans. Mix india ink with body fluids (especially CSF), yeasts appear bright. 9-6 |
|
|
Term
| Name the yeast for which there is an antigen test. |
|
Definition
| Cryptococcus neoformans. 9-6 |
|
|
Term
| What is the treatment for Cryptococcus neoformans? |
|
Definition
| Amphotericin and flucytosine. Followed by fluconazole for maintenance. 9-7 |
|
|
Term
| What is the main site of entry for Aspergillus? where does it go from there? |
|
Definition
| Respiratory tract (inhalation of spores). From there it evades pulmonary macrophages, can enter the lungs, and proceed into the blood vessels, which provide a route to other parts of the body (e.g. brain) 9-7 |
|
|
Term
| Name the 5 manifestations of aspergillus in a certain part of the body. . . |
|
Definition
Manifestations in the lungs:
Airway colonization
Allergic bronchopulmonary aspergillosis (ABPA) (Chronic allergic response to colonization with aspergillus)
Aspergilloma
Invasive pulmonary aspergillosis
Disseminated aspergillosis 9-7 |
|
|
Term
| What is the antigen that can be detected with aspergillosis? |
|
Definition
|
|
Term
| The presence of galactomannan antigen indicates which pathogen may be present? |
|
Definition
|
|
Term
| Aspergillus is susceptible to... |
|
Definition
Amphotericin formulations Voriconazole, posaconazole, or itraconazole Echinocandins
Voricanazole is the drug of choice.
NOT fluconazole
9-9 |
|
|
Term
| Which fungal infection may go from the sinuses to the brain? |
|
Definition
|
|
Term
| Most molds enter the body through inhalation, but this one enters through puncture wounds in the skin. |
|
Definition
| What is Sporothrix schenckii? 9-9 |
|
|
Term
| Rose gardeners disease is caused by... |
|
Definition
| Sporothrix schenckii. 9-9 |
|
|
Term
| Which fungus causes a string of red, nodular lesions? |
|
Definition
| Sporothrix schenckii. 9-9 |
|
|
Term
| Name the other molds we should know, but don't have any other information about. |
|
Definition
Dematiaceous molds
Penicillium marneffei
Fusarium
Scedosporium 9-10 |
|
|
Term
| Two dimorphic fungi are commonly found in the Ohio and Mississippi River area. Which are they? |
|
Definition
| Histoplasma capsulatum, and Blastomyces dermatitidis. 9-10,11 |
|
|
Term
| Where is Coccidioides immitis found in the US? AKA? |
|
Definition
| Southwestern states. "Valley Fever" 9-10 |
|
|
Term
| Name the clinical presentations of histoplasma capsulatum. |
|
Definition
| respiratory infection. >90% Mediastinal granuloma and fibrosis 9-10 |
|
|
Term
| Name the fungus that lacks ergosterol. |
|
Definition
| Pneumocystis jiroveci. 9-10 |
|
|
Term
| Which course of antibiotics is given to T cell impaired individuals to prevent Pneumocystis jiroveci infection? |
|
Definition
| Trimethoprim/sulfamethoxazole. (or Bactrim) 9-12 |
|
|
Term
| What kind of organism is a dermatophyte? |
|
Definition
|
|
Term
| Name the zoophilic dermatophytes. |
|
Definition
| Microsporum canis. It is the only one. 9-12 |
|
|
Term
| Name the anthropophilic dermatophyte. |
|
Definition
|
|
Term
| Which fungus will fluoresce green under ultraviolet light (Wood's light)? |
|
Definition
|
|
Term
| What is the treatment for dermatophytes? |
|
Definition
| Imidazoles topically. azoles orally. 9-12 |
|
|
Term
| T/F: Chitin is found in all fungi |
|
Definition
|
|
Term
| How do fungi reproduce? Bacteria? |
|
Definition
fungi: sexually
bacteria: asexually |
|
|
Term
| Is the following a characteristic of a yeast or mold?: form smooth flat colonies. |
|
Definition
|
|
Term
| What are aka filamentous fungi? |
|
Definition
|
|
Term
| Is the following a characteristic of a yeast or mold? Composed of hyphae. |
|
Definition
|
|
Term
| Describe the structure of fungal cell membrane and cell wall. |
|
Definition
| From inside to out: cell membrane with sterols (ergosterol and zymosterol embedded); chitin; glucans (beta 1,6 and beta 1,3); mannan (made of mannoproteins) |
|
|
Term
| What types of fungi is amphotercin active against? |
|
Definition
| almost all fungi, because almost all fungi have ergosterol in their membranes. |
|
|
Term
| What is the classic antifungal drug? How does it work? |
|
Definition
| Amphotericin B. Like all amphotericins, it works by binding to ergosterol in fungal cytoplasmic membrane, thereby causing membrane permeability to increase. |
|
|
Term
| What drug would you use for cutaneous fungal infections? |
|
Definition
| imidazole (it's a topical agent) |
|
|
Term
| What drug (azole) would you use for more serious fungal infections? |
|
Definition
|
|
Term
| What azole drug would you use for Candida infections? |
|
Definition
| Fluconazole, voriconazole, itraconazole, posaconazole. |
|
|
Term
| What azole drugs could you use for mold infections? |
|
Definition
| Itraconazole, voriconazole, and posaconazole. NOT fluconazole. |
|
|
Term
| What can happen if you infuse antifungal echinocandins too rapidly? |
|
Definition
| You can get a histamine-like rxn. |
|
|
Term
| What fungi can you use echinocandins against? |
|
Definition
Active against Candida spp. and Aspergillus (used for serious infections)
NOT ACTIVE against Cryptococcus and Zygomycetes (b/c they have a lot of beta 1,6 glucon in cell wall and echinocandins are active against beta 1,3 glucon)
9-4 |
|
|
Term
|
Definition
| azoles are antifungals. they are usua. well tolerated. Liver toxicity with elevation of transaminases may occur. |
|
|
Term
| How are ecinocandins metabolized? |
|
Definition
| by the liver, which means you don't have to adjust your dose based on renal function. |
|
|
Term
| side effects to worry about with flucytosine? |
|
Definition
| bone marrow suppression, rash, diarrhea. More common in patients with impaired renal function. |
|
|
Term
| Candida albicans has historically been the most frequent species to infect humans. Why then are non-albicans species (such as C. glabrata) becoming more common isolates in hospitalized patients? |
|
Definition
| Because C. glabrata is less susceptible to fluconazole than is C. albicans. (Fluconazole is a widely used prophylactic to prevent fungal infections) C. glabrata fills the niche that is voided by C. albicans. |
|
|
Term
| Where do you normally find Candida spp.? What type of bug are they? |
|
Definition
| normal inhabitants of mouth, GI tract, vagina. They are fungi (yeasts) |
|
|
Term
| What kinds of diseases does Candida spp. cause? |
|
Definition
| wide spectrum: superficial invasion of the mouth (thrush), esophagus, vagina, and skin (diaper rash), abscesses, bacteremia |
|
|
Term
| Where does Crytococcus neoformans live? |
|
Definition
| all over the world, certain trees and rotting wood, droppings of some birds (pigeons) |
|
|
Term
| How does C. neoformans get inside the body? |
|
Definition
|
|
Term
| Diseases caused by Crytococcus neoformans? |
|
Definition
most important: crytococcal meningitis
pneumonia
skin and bloodstream infections |
|
|
Term
| What do lymphocytes have to do with Cryptococcus neoformans? |
|
Definition
| Human lymphocytes (especially CD4+ cells) inhibit growth of C. neoformans by direct contact. So, T lymphocyte deficiencies (AIDS, transplant patients) are major risk factors for cryptococcal meningitis. |
|
|
Term
| What are dimorphic fungi? |
|
Definition
grow in host as yeast-like forms
grow at room temp in vitro as molds
e.g. histoplasmosis, blastomycosis, sporotrichosis, and coccidoidomycosis |
|
|
Term
| What type of organism is histoplasmosis? |
|
Definition
|
|
Term
| What type of organism is a zygomycete? What is the most common form of zygomycosis? |
|
Definition
| It's a mold. Most common form is rhinocerebral disease. |
|
|
Term
| How does a zygomycete get into the body and where does it go from there? |
|
Definition
| Spores are inhaled into respiratory tract. Spores may also stay in the nose and when bacteria grow they invade first the sinuses and then the brain. |
|
|
Term
| What kind of organism is Sporothrix schenckii? |
|
Definition
|
|
Term
| Describe the geographically restricted dimorphic fungi in general (what are the 3 we talked about?) How are they acquired, how do they manifest? How are they treated? |
|
Definition
We talked about: Histoplasmosa capsulatum
Caccidioides immitis
Blastomyces dermatitidis
Acquired vis respiratory tract
Manifest as pneumonia or disseminated infections (esp. in immunocompromised)
All can be treated with Amphotericin |
|
|
Term
| How does Pneumocystis jiroveci manifest? |
|
Definition
| pneumonia (in individuals with T cell impairment) |
|
|
Term
| What disease does Microsporum canis cause? What kind of organism is it? |
|
Definition
Causes ring worm (tinea corporis)
It's a zoophilic dermatophyte (mold) |
|
|
Term
| What causes ring worm? What is ring work aka? |
|
Definition
aka tinea corporis
caused by Microsporum canis (a zoophilic dermatophyte (mold)) |
|
|
Term
| What causes athlete's foot, and what is athlete's foot aka? |
|
Definition
caused by Trichophyton rubrum (anthropophilic dermatophyte (mold))
athlete's foot aka tinea pedis |
|
|
Term
| What causes jock itch? What is jock itch aka? |
|
Definition
jock itch aka tinea cruris
caused by Trichophyton rubrum (anthropophilic dermatophyte) |
|
|
Term
| What does Trichophyton rubrum cause? |
|
Definition
jock itch (tinea cruris)
athlete's food (tinea pedis) |
|
|
Term
| What kinds of fungal organisms usually cause infection of the nails? Infection of nails aka? |
|
Definition
Anthropophilic dermatophytes (molds).
infection of nails aka onychomycosis |
|
|
Term
| What is the nutrition source for dermatophytes? where are dermatophytes commonly found? |
|
Definition
keratin
found all over the world, more common in tropical areas |
|
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