Weekly Year 3: Medical Mycology Exam - September 11, 2026...

Question 1

An organism without a known sexual stage of reproduction would be classified in which of the following fungal groups?

Accepted Answer

Deuteromycota (Fungi Imperfecti) — Fungi with no known teleomorph (sexual stage) are classified as Deuteromycota, also known as Fungi Imperfecti or Mitosporic fungi.

Question 2

An antifungal drug such as Miconazole inhibits proper formation of which cellular component?

Accepted Answer

Plasma membrane ergosterol — Azoles, such as miconazole, inhibit the enzyme lanosterol 14α-demethylase, which is crucial for ergosterol synthesis. Ergosterol is a vital component of fungal plasma membranes, and its disruption leads to cell death.

Question 3

Which of the following fungi would you most likely find growing in pigeon droppings?

Accepted Answer

Cryptococcus neoformans — Cryptococcus neoformans is an encapsulated yeast that is commonly found in soil contaminated with pigeon or bird droppings. Inhalation of the yeast can lead to cryptococcosis, particularly in immunocompromised individuals.

Question 4

Which fungal condition causes more than 200 million cases per year worldwide, with symptoms including an itching sensation and burning internal pain?

Accepted Answer

Vulvovaginal candidiasis — Vulvovaginal candidiasis (yeast infection) is extremely common globally, affecting millions annually, and is characterized by intense itching and a burning sensation.

Question 5

The formation of arthrospores and spherules in infected tissue is characteristic of which fungal disease?

Accepted Answer

Coccidioidomycosis — Coccidioides species exist as arthroconidia in the environment (soil) and develop into characteristic large, multinucleated spherules within host tissues during infection.

Question 6

Aflatoxin is produced by which organism, and what type of substance is it?

Accepted Answer

Aspergillus flavus; hepatocarcinogen — Aspergillus flavus is a common mold that produces aflatoxins, which are potent mycotoxins known to be hepatocarcinogenic (liver-damaging and cancer-causing).

Question 7

A girl who pricked her finger while pruning rose bushes develops a local pustule that progresses to an ulcer. Several nodules then develop along the local lymphatic drainage. What is the most likely causative agent?

Accepted Answer

Sporothrix schenckii — This presentation is classic for lymphocutaneous sporotrichosis, often referred to as 'rose gardener's disease,' caused by the fungus Sporothrix schenckii, which is found on plants and in soil.

Question 8

Fungal cells that reproduce by budding are seen in the infected tissues of patients with which of the following combinations?

Accepted Answer

Candida albicans, Cryptococcus neoformans, Sporothrix schenckii — Candida, Cryptococcus, and Sporothrix are all dimorphic fungi that exist as budding yeasts in tissue form.

Question 9

Which statement regarding paracoccidiomycosis is NOT correct?

Accepted Answer

It is caused by Paracoccidioides brasiliensis. — Paracoccidioides brasiliensis is susceptible to Amphotericin B; it is not resistant.

Question 10

A kidney transplant patient develops nosocomial systemic candidiasis. The isolated Candida glabrata is resistant to fluconazole. Which of the following would be a reasonable oral alternative?

Accepted Answer

Posaconazole — Posaconazole retains activity against many strains of fluconazole-resistant Candida, including Candida glabrata. Voriconazole is also an option, but posaconazole is often preferred for oral maintenance therapy in such cases.

Question 11

All are characteristics of systemic/deep mycosis EXCEPT:

Accepted Answer

They primarily affect the epidermis and dermis. — Systemic/deep mycoses invade deeper tissues and organs, not primarily the epidermis and dermis, which are characteristic of superficial and cutaneous mycoses.

Question 12

Thousands in the western USA experienced a flu-like illness in 1992 from inhaling soil fungal spores, termed 'valley fever.' What is the pathogen responsible?

Accepted Answer

Coccidioides immitis — Coccidioidomycosis, also known as Valley Fever, is endemic to the southwestern United States and is caused by inhaling spores of Coccidioides immitis or Coccidioides posadasii.

Question 13

Amphotericin B would be used to treat all of the following EXCEPT:

Accepted Answer

Tinea pedis — Amphotericin B is a broad-spectrum antifungal typically used for severe systemic fungal infections. Tinea pedis (athlete's foot) is a superficial fungal infection usually treated with topical antifungals.

Question 14

All of the following are superficial mycoses EXCEPT:

Accepted Answer

Candidiasis — Candidiasis can be superficial (e.g., oral thrush, vulvovaginal candidiasis) but also invasive and systemic, affecting deeper tissues and organs, thus it's not solely a superficial mycosis.

Question 15

Which of the following statements regarding Tinea nigra is NOT correct?

Accepted Answer

It is a dermatophytosis. — Tinea nigra is caused by Exophiala werneckii (formerly Hortaea werneckii) and is characterized by superficial discoloration of the skin, but it is not a dermatophytosis, which are infections caused by dermatophytes.

Question 16

Which of the following is the common cause of Athlete's foot?

Accepted Answer

Dermatophytes (e.g., Trichophyton rubrum) — Athlete's foot (Tinea pedis) is most commonly caused by dermatophytes, with Trichophyton species being the most frequent culprits. Epidermophyton floccosum also causes athlete's foot.

Question 17

All of the following are characteristics of cutaneous mycoses EXCEPT:

Accepted Answer

They are often asymptomatic. — Cutaneous mycoses, while affecting keratinized tissues, are often symptomatic, causing itching, scaling, and inflammation, rather than being asymptomatic.

Question 18

All of the following dermatophytes are responsible for nail infections EXCEPT:

Accepted Answer

Microsporum canis — Microsporum species, including Microsporum canis, are primarily associated with hair and skin infections, not typically nail infections (onychomycosis).

Question 19

Which of the following is an opportunistic pathogenic fungus in humans?

Accepted Answer

Candida albicans — Candida albicans is a commensal organism in many individuals but can become pathogenic and cause serious infections (opportunistic) in immunocompromised hosts or when normal flora is disrupted.

Question 20

Aspergillosis is recognized in tissue by the presence of:

Accepted Answer

Septate hyphae with acute angle branching — Aspergillus species are characterized by septate hyphae with characteristic dichotomous (acute angle) branching.

Question 21

Fungi often colonize lesions caused by other agents. Which is LEAST likely to be present as a colonizer?

Accepted Answer

Staphylococcus aureus — Staphylococcus aureus is a bacterium, not a fungus, and while it can cause skin lesions, it is not a fungal colonizer in the same way as the listed fungi.

Question 22

Which statement regarding dermatophytosis is correct?

Accepted Answer

Dermatophytoses are caused by molds that infect keratinized tissues. — Dermatophytoses, such as ringworm, are fungal infections caused by dermatophytes (molds) that exclusively infect keratinized tissues like skin, hair, and nails.

Question 23

Which statement regarding laboratory identification of fungi is correct?

Accepted Answer

KOH preparation is used to visualize fungal elements in skin scrapings. — A potassium hydroxide (KOH) preparation is a common laboratory technique used to digest keratinized material in skin scrapings, hair, and nails, making fungal elements like hyphae and spores more visible under microscopy.

Question 24

All of the following are examples of superficial mycoses EXCEPT:

Accepted Answer

Candidiasis — Candidiasis can manifest as a superficial infection but is also known for causing invasive and systemic diseases, unlike the other options which are exclusively superficial mycoses.

Question 25

Amphotericin B would be used to treat all of the following EXCEPT:

Accepted Answer

Tinea pedis — Amphotericin B is reserved for severe systemic fungal infections. Tinea pedis (athlete's foot) is a superficial fungal infection typically managed with topical antifungals.

Question 26

A component of the cell membrane of most fungi is:

Accepted Answer

Ergosterol — Ergosterol is the primary sterol found in the plasma membrane of most fungi, analogous to cholesterol in mammalian cell membranes. It is a key target for many antifungal drugs, such as azoles.

Question 27

Which statement regarding dermatophytosis is correct?

Accepted Answer

Dermatophytoses infect keratinized tissues. — Dermatophytes are a group of fungi that infect keratinized structures of the body, including the stratum corneum of the skin, hair, and nails.

Question 28

Which statement regarding laboratory identification of fungi is correct?

Accepted Answer

India ink is the primary stain for diagnosing candidiasis. — Direct microscopic examination of clinical specimens (e.g., skin scrapings, sputum) using a KOH preparation is a rapid and effective method for visualizing fungal hyphae and yeasts.

Question 29

Which of the following is an opportunistic pathogenic fungus in humans?

Accepted Answer

Aspergillus fumigatus — Aspergillus fumigatus is a ubiquitous mold that can cause serious opportunistic infections (aspergillosis), particularly in immunocompromised individuals, such as those with neutropenia or on corticosteroids.

Question 30

Aspergillosis is recognized in tissue by the presence of:

Accepted Answer

Septate hyphae with dichotomous branching — Histological examination of tissue infected with Aspergillus reveals characteristic septate hyphae with acute-angled (dichotomous) branching.

Question 31

Fungi often colonize lesions caused by other agents. Which of the following is LEAST likely to be present as a colonizer?

Accepted Answer

Streptococcus pyogenes — Streptococcus pyogenes is a bacterium and would not typically 'colonize' a lesion in the same way as fungi that are part of the normal flora or environmental contaminants; it would typically be a primary pathogen causing the lesion or a secondary bacterial infection.

Question 32

Each of the following statements concerning Cryptococcus neoformans is correct EXCEPT:

Accepted Answer

It is typically treated with fluconazole alone for cryptococcal meningitis. — Cryptococcal meningitis is a serious infection that is usually treated with a combination of amphotericin B and flucytosine, followed by a consolidation phase with fluconazole. Fluconazole alone is often insufficient for initial treatment of meningitis.

Question 33

Each of the following statements concerning Candida albicans is correct EXCEPT:

Accepted Answer

It is easily identified by its characteristic arthroconidia in tissue. — Candida albicans typically appears as budding yeasts and pseudohyphae in tissue. Arthroconidia are characteristic of Coccidioides immitis.

Question 34

Natural habitat for Paracoccidioides brasiliensis is:

Accepted Answer

Soil and decaying vegetation — Paracoccidioides brasiliensis is found in soil and on decaying vegetation, particularly in tropical and subtropical regions of South and Central America.

Question 35

Coccidioidomycosis is also called:

Accepted Answer

San Joaquin Valley Fever — Coccidioidomycosis is commonly known as Valley Fever, originating from the San Joaquin Valley in California, where it is endemic.

Question 36

One of the most common mycotoxins that infects nuts and grains and causes severe reactions is:

Accepted Answer

Aflatoxin — Aflatoxins, produced by Aspergillus flavus and Aspergillus parasiticus, are potent mycotoxins that frequently contaminate staple foods like nuts and grains, and are known for their severe toxic and carcinogenic effects.

Weekly Year 3: Medical Mycology Exam - September 11, 2026...

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