Weekly Year 3: Medical Mycology Exam - September 25, 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 historically classified as Fungi Imperfecti or Deuteromycota. Modern classification reassigns them to existing phyla based on molecular data.

Question 2

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

Accepted Answer

Plasma membrane due to ergosterol disruption — Azole antifungals like miconazole inhibit ergosterol synthesis, which is a crucial component of the fungal plasma membrane, disrupting its integrity and function.

Question 3

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

Accepted Answer

Cryptococcus neoformans — Cryptococcus neoformans is commonly found in soil contaminated with bird droppings, particularly from pigeons.

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, often caused by Candida albicans, is extremely common globally and is characterized by itching and internal burning sensations.

Question 5

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

Accepted Answer

Coccidioidomycosis — Coccidioides species form arthroconidia in the soil (mold form) and develop into spherules containing endospores within infected human tissues.

Question 6

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

Accepted Answer

Aspergillus flavus; a potent hepatocarcinogen — Aspergillus flavus produces aflatoxins, which are a group of potent toxins known to be hepatocarcinogenic (cancer-causing to the liver).

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, commonly known as 'rose gardener's disease,' caused by Sporothrix schenckii.

Question 8

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

Accepted Answer

Aspergillus fumigatus only — Candida, Cryptococcus, and Sporothrix all typically appear as budding yeasts in tissue specimens.

Question 9

Which statement regarding paracoccidiomycosis is NOT correct?

Accepted Answer

It is caused by Paracoccidioides brasiliensis. — Paracoccidioides brasiliensis is susceptible to amphotericin B; resistance would be an incorrect statement.

Question 10

A kidney transplant patient develops a 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 often retains activity against Candida species that are resistant to fluconazole, making it a suitable oral alternative in this scenario.

Question 11

All of the following are generally considered characteristics of systemic/deep mycoses EXCEPT:

Accepted Answer

They always originate from an exogenous source like soil inhalation. — While many systemic fungal infections originate from exogenous sources like soil inhalation (e.g., histoplasmosis, coccidioidomycosis), candidiasis can also arise from endogenous sources (e.g., gut flora) or through medical devices like catheters.

Question 12

Thousands of people in the western USA experienced a flu-like illness in 1992 after inhaling soil fungal spores, leading to what is commonly known as 'valley fever.' What is the pathogen responsible?

Accepted Answer

Coccidioides immitis — Coccidioidomycosis, caused by Coccidioides immitis and Coccidioides posadasii, is commonly referred to as Valley Fever and is endemic to the southwestern United States. Inhalation of spores from the soil leads to the infection.

Question 13

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

Accepted Answer

Superficial tinea infections — Amphotericin B is a potent antifungal used for severe systemic fungal infections. Superficial tinea infections are typically treated with topical antifungals.

Question 14

All of the following are generally classified as superficial mycoses EXCEPT:

Accepted Answer

Candidiasis — While Candida can cause superficial skin infections, it is also a significant cause of mucocutaneous and systemic (deep) infections, particularly in immunocompromised individuals. Tinea pedis, pityriasis versicolor, and Tinea nigra are classic superficial mycoses affecting the outermost layers of skin and hair.

Question 15

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

Accepted Answer

It requires systemic antifungal therapy for treatment. — Tinea nigra is a superficial fungal infection that typically responds well to topical antifungal agents and is not usually considered a dermatophytosis (caused by dermatophytes) but rather by dematiaceous fungi like Hortaea werneckii.

Question 16

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

Accepted Answer

Trichophyton rubrum — Tinea pedis, commonly known as athlete's foot, is most frequently caused by dermatophytes, with Trichophyton rubrum being the most prevalent species.

Question 17

All of the following are generally considered characteristics of cutaneous mycoses EXCEPT:

Accepted Answer

They can spread to deeper tissues and become systemic. — Cutaneous mycoses, by definition, are confined to the keratinized structures and do not typically invade deeper tissues. When they do, they are no longer considered solely cutaneous.

Question 18

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

Accepted Answer

Microsporum canis — Microsporum species primarily infect hair and skin, rarely nails. Trichophyton rubrum, Epidermophyton floccosum, and Trichophyton mentagrophytes are common causes of onychomycosis.

Question 19

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

Accepted Answer

Candida albicans — Candida albicans is considered an opportunistic pathogen, meaning it can cause disease in individuals with compromised immune systems or when normal flora are disrupted. While the others can cause disease, Candida is a prime example of an opportunistic fungus.

Question 20

Aspergillosis is recognized in tissue by the presence of:

Accepted Answer

Hyphae with characteristic 45-degree branching — Tissue sections of Aspergillus infections typically show septate hyphae that exhibit characteristic dichotomous (45-degree) branching.

Question 21

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

Accepted Answer

Dermatophytes — Dermatophytes are primarily parasitic on keratinized tissues and are less likely to be found as incidental colonizers of non-keratinized lesions compared to Candida, Staph aureus, or Aspergillus, which are common environmental or commensal organisms that can opportunistically grow in damaged tissue.

Question 22

Which statement regarding dermatophytosis is correct?

Accepted Answer

Dermatophytes are fungi that require keratin to grow. — Dermatophytes are a group of fungi that produce enzymes to digest keratin, the main protein in skin, hair, and nails, thus they are adapted to infect these structures.

Question 23

Which statement regarding laboratory identification of fungi is correct?

Accepted Answer

Direct microscopic examination of KOH preparations is useful for visualizing fungal elements in clinical specimens. — A potassium hydroxide (KOH) wet mount is a standard laboratory technique for preparing clinical specimens to visualize fungal elements like hyphae and yeasts.

Question 24

All of the following are examples of superficial mycoses EXCEPT:

Accepted Answer

Disseminated candidiasis — Disseminated candidiasis is a deep, systemic infection, not a superficial mycosis. Tinea corporis, pityriasis versicolor, and tinea capitis affect the outermost layers of the skin or hair.

Question 25

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

Accepted Answer

Tinea cruris (jock itch) — Amphotericin B is a broad-spectrum antifungal reserved for severe systemic fungal infections. Tinea cruris is a superficial dermatophyte infection typically treated 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 fungal cell membranes, analogous to cholesterol in mammalian cell membranes. It is a common target for antifungal drugs.

Question 27

Which statement regarding dermatophytosis is correct?

Accepted Answer

Dermatophytes invade keratinized tissues. — Dermatophytes are fungi that specialize in invading and breaking down keratin, the protein found in skin, hair, and nails, leading to infections in these structures.

Question 28

Which statement regarding laboratory identification of fungi is correct?

Accepted Answer

India ink is used to detect the capsule of Cryptococcus neoformans. — Histoplasma capsulatum is a dimorphic fungus; it exists as a yeast in tissue and as a mold (mycelial form) in the environment or culture. India ink is used for Cryptococcus neoformans capsule visualization. Blood agar is not the primary medium for yeast identification, and Malassezia furfur is not well visualized by Gram stain.

Question 29

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

Accepted Answer

Aspergillus fumigatus — Aspergillus fumigatus is a common opportunistic pathogen, particularly affecting immunocompromised individuals, causing invasive aspergillosis. The others are typically endemic dimorphic fungi that cause primary infections.

Question 30

Aspergillosis is recognized in tissue by the presence of:

Accepted Answer

Hyaline septate hyphae with dichotomous branching — Histological examination of tissue infected with Aspergillus reveals hyaline (clear), septate hyphae with characteristic acute-angled or 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 in such lesions?

Accepted Answer

Dermatophytes — Dermatophytes are obligate parasites of keratinized tissues and are less likely to colonize non-keratinized lesions compared to opportunistic organisms like Candida, Staphylococcus aureus, or Aspergillus.

Question 32

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

Accepted Answer

It is a common cause of meningitis in immunocompetent individuals. — While Cryptococcus neoformans can cause meningitis in immunocompetent individuals, it is far more common and severe in immunocompromised patients (e.g., those with HIV/AIDS).

Question 33

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

Accepted Answer

It is a dimorphic fungus. — Candida albicans is not considered a dimorphic fungus in the same way as Histoplasma or Coccidioides. While it can exist in yeast form and develop pseudohyphae and true hyphae, it does not have distinct yeast and mold phases in the environment and tissue like true dimorphic fungi.

Question 34

Natural habitat for Paracoccidioides brasiliensis is:

Accepted Answer

Soil in endemic areas of Latin America — Paracoccidioides brasiliensis is endemic to Latin America, and its natural habitat is believed to be the soil, particularly in association with vegetation.

Question 35

Coccidioidomycosis is also called:

Accepted Answer

San Joaquin Valley Fever — Coccidioidomycosis is commonly known as Valley Fever, and specifically San Joaquin Valley Fever due to its endemicity in that region of California. Other options refer to different fungal diseases.

Question 36

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

Accepted Answer

Aflatoxin — Aflatoxins, produced primarily by Aspergillus flavus and Aspergillus parasiticus, are among the most potent mycotoxins, commonly found contaminating crops like corn, peanuts, and other nuts and grains. They are known for their carcinogenic properties, particularly hepatotoxicity.

Weekly Year 3: Medical Mycology Exam - September 25, 2026...

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