Question 1

The agency that provides documents and sets standards for antifungal susceptibility testing is the:&#10;A)National Accrediting Agency for Clinical Library Sciences (NAACLS).&#10;B)Association of Specialized and Cooperative Library Agencies (ASCLS).&#10;C)College of American Pathologists (CAP).&#10;D)Clinical Laboratory Standards Institute (CLSI).

Accepted Answer

The Clinical Laboratory Standards Institute (CLSI),formerly the National Committee for Clinical Laboratory Standards (NCCLS),provides documents and sets standards for antifungal susceptibility testing.Their website is available at www.nccls.org.

Question 2

A patient who is positive for the human immunodeficiency virus (HIV)is diagnosed with a Cryptococcus neoformans infection.The attending resident prescribed Griseofulvin;however,the patient's condition did not seem to improve.Which one of the following statements explains this discrepancy?

A)The dose should be increased to penetrate the blood-brain barrier.
B)Nystatin,which would have been more effective,should have been prescribed.
C)Griseofulvin is not effective against C.neoformans;therefore the therapy should be changed.
D)Potassium iodide is the therapy of choice,not griseofulvin.

C
Fluconazole has excellent activity against most Candida spp.and C.neoformans;therapeutic levels are easily reached in the central nervous system.Griseofulvin is an oral agent used to treat dermatophytosis fungal infections;therefore the wrong antifungal was prescribed to this patient.

Accepted Answer

Fluconazole has excellent activity against most Candida spp.and C.neoformans;therapeutic levels are easily reached in the central nervous system.Griseofulvin is an oral agent used to treat dermatophytosis fungal infections;therefore the wrong antifungal was prescribed to this patient.

Question 3

MATCHING&#10;Match the antifungal agent with its mode of action.&#10;a.Amphotericin B&#10;b.Griseofulvin&#10;c.5-Fluorocytosine&#10;d.Echinocandin&#10;e.Azole&#10;Is a glucan synthesis inhibitor

Accepted Answer

Echinocandins are glucan synthesis inhibitors, meaning they disrupt the production of glucans, a key component of fungal cell walls. This leads to weakened cell walls and ultimately cell death.

Answer: B
 Griseofulvin targets fungal cell division by inhibiting microtubule formation, which prevents the fungus from replicating properly.

Answer: C
 5-Fluorocytosine (5-FC) interferes with fungal RNA and protein synthesis, leading to inhibition of fungal growth and replication.

Answer: E
 Azoles inhibit the synthesis of ergosterol, a key component of the fungal cell membrane. This disruption of the cell membrane leads to structural instability and ultimately cell death.

Answer: A
 Amphotericin B works by binding to ergosterol in the fungal cell membrane, leading to membrane disruption and cell death. It does not target glucan synthesis specifically.

Question 4

MATCHING&#10;Match the antifungal agent with its mode of action.&#10;a.Amphotericin B&#10;b.Griseofulvin&#10;c.5-Fluorocytosine&#10;d.Echinocandin&#10;e.Azole&#10;Alters membrane permeability

Accepted Answer

The answer of MATCHING&#10;Match the antifungal agent with its mode...

Question 5

MATCHING&#10;Match the antifungal agent with its mode of action.&#10;a.Amphotericin B&#10;b.Griseofulvin&#10;c.5-Fluorocytosine&#10;d.Echinocandin&#10;e.Azole&#10;Binds microtubular proteins

Accepted Answer

Griseofulvin binds to microtubular proteins, disrupting the mitotic spindle and inhibiting fungal cell mitosis.

Question 6

The Reference Method for Broth Dilution Antifungal Susceptibility Testing of Filamentous Fungi;Approved Standard (M38-A2)describes the guidelines for antifungal susceptibility testing for molds.The suspension must be standardized with a spectrophotometer.Susceptibility testing is determined by which method?

A)Disk diffusion
B)Microdilution
C)Broth dilution
D)Immunodiffusion

Accepted Answer

M38-A2 is an approved microdilution method for antifungal susceptibility testing for molds;it also suggests using the Roswell Park Memorial Institute (RPMI)-1640 medium with 4-morpholinepropanesulfonic (MOPS)acid in yeast testing.The suspension must be standardized with a spectrophotometer.The amount of growth in each well should be compared with the growth in the control well.

Question 7

MATCHING&#10;Match the antifungal agent with its mode of action.&#10;a.Amphotericin B&#10;b.Griseofulvin&#10;c.5-Fluorocytosine&#10;d.Echinocandin&#10;e.Azole&#10;Inhibits protein synthesis

Accepted Answer

5-Fluorocytosine works by being converted into 5-fluorouracil within fungal cells, which then inhibits fungal protein synthesis by interfering with the synthesis of pyrimidine, a nucleotide necessary for DNA and RNA synthesis.

Question 8

MATCHING&#10;Match the antifungal agent with its mode of action.&#10;a.Amphotericin B&#10;b.Griseofulvin&#10;c.5-Fluorocytosine&#10;d.Echinocandin&#10;e.Azole&#10;Interferes with ergosterol synthesis

Accepted Answer

Azoles work by inhibiting the synthesis of ergosterol, a critical component of fungal cell membranes.

Question 9

A patient is diagnosed with an invasive Aspergillosis infection.The antifungal therapy that should be administered is:&#10;A)nystatin.&#10;B)griseofulvin.&#10;C)amphotericin B.&#10;D)fluconazole.

Accepted Answer

Amphotericin B is produced by the actinomycete Streptomyces nodosus.It is commonly infused intravenously to treat deep-seated fungal infections (e.g. ,invasive aspergillosis),as well as those caused by Candida spp. ,Cryptococcus,and members of the Zygomycetes family.

Deck 62: Anti-fungal Susceptibility Testing, therapy, and Prevention