Weekly Year 3: Medical Mycology Exam - October 2, 2026 (S...

Question 1

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

Accepted Answer

Deuteromycetes (Fungi Imperfecti) — Fungi with no known teleomorph (sexual stage) are classified as Deuteromycetes, also known as Fungi Imperfecti or Mitosporic fungi. This classification is based on their asexual reproductive structures.

Question 2

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

Accepted Answer

Ergosterol — Azole antifungals like miconazole work by inhibiting the synthesis of ergosterol, a key component of fungal cell membranes, thereby disrupting their formation and integrity.

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 those of pigeons. Inhalation of these encapsulated yeasts can lead to cryptococcosis.

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 characterized by itching, burning, and discharge.

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 the host's tissues. This is a hallmark of Coccidioidomycosis.

Question 6

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

Accepted Answer

Aspergillus flavus; hepatocarcinogen — Aspergillus flavus produces aflatoxins, which are potent mycotoxins and known hepatocarcinogens, often contaminating grains and nuts.

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 Sporothrix schenckii, which enters the body through minor trauma.

Question 8

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

Accepted Answer

Coccidioides and Histoplasma — Candida, Cryptococcus, and Sporothrix all typically appear as budding yeasts in tissue samples. Other dimorphic fungi like Histoplasma and Coccidioides have different characteristic forms in tissue.

Question 9

Which statement regarding paracoccidiomycosis is NOT correct?

Accepted Answer

Patients may present with oral ulcers. — Paracoccidioides brasiliensis is susceptible to amphotericin B. Resistance to amphotericin B is not a characteristic of this fungus.

Question 10

A kidney transplant patient develops nosocomial systemic candidiasis. Candida glabrata is isolated and found to be 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 such cases.

Question 11

All are characteristics of systemic/deep mycosis EXCEPT:

Accepted Answer

They are always caused by fungi classified as Deuteromycetes. — Systemic mycoses are not exclusively caused by Deuteromycetes; many are caused by fungi with known sexual stages (e.g., Ascomycetes, Basidiomycetes). Also, not all systemic infections start in the lungs; some can be associated with indwelling devices or gastrointestinal colonization.

Question 12

Thousands experienced a flu-like illness in the western USA in 1992 after inhaling soil fungal spores, a condition known as 'valley fever.' What is the pathogen?

Accepted Answer

Coccidioides immitis — Coccidioidomycosis, also known as Valley Fever, is endemic to the southwestern United States and is caused by Coccidioides immitis or C. posadasii, which are inhaled as arthroconidia from soil.

Question 13

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

Accepted Answer

Superficial dermatophytosis — Amphotericin B is a potent antifungal used for severe systemic fungal infections. Superficial dermatophytoses are typically treated with topical or oral azoles or terbinafine.

Question 14

All of the following are superficial mycoses EXCEPT:

Accepted Answer

Pityriasis capitis — Pityriasis capitis, commonly known as dandruff, is a scaling of the scalp, often associated with Malassezia species, but it's generally considered a condition of the stratum corneum or a mild form of superficial mycosis, whereas Tinea versicolor, Tinea nigra, and Tinea cruris are classic examples of superficial mycoses affecting skin and hair.

Question 15

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

Accepted Answer

It is a deep, invasive fungal infection. — Tinea nigra is a superficial fungal infection that causes dark (hyperpigmented) macules, typically on the palms and soles. It is caused by Exophiala werneckii and is treated with topical antifungals. It is not a deep, invasive infection.

Question 16

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

Accepted Answer

Trichophyton rubrum — Trichophyton rubrum is the most common cause of Tinea pedis (athlete's foot), although other dermatophytes like Epidermophyton floccosum and Trichophyton mentagrophytes can also be responsible.

Question 17

All of the following are characteristics of cutaneous mycoses EXCEPT:

Accepted Answer

They can spread systemically to cause deep infections. — While cutaneous mycoses primarily affect the keratinized tissues (skin, hair, nails) and are often caused by dermatophytes, they generally do not spread systemically to cause deep infections. Systemic spread is more characteristic of deep mycoses.

Question 18

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

Accepted Answer

Candida albicans — Candida albicans can cause nail infections (onychomycosis), but it is a yeast, not a dermatophyte. Trichophyton rubrum, Trichophyton tonsurans, and Epidermophyton floccosum are all dermatophytes known to cause nail infections.

Question 19

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

Accepted Answer

Aspergillus fumigatus — Aspergillus fumigatus is an opportunistic pathogen that causes aspergillosis, particularly in immunocompromised individuals. While the others can cause significant disease, they are often considered primary pathogens in certain contexts, though immunocompromise can increase susceptibility.

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 that exhibit acute-angle (approximately 45-degree) branching. Spherules with endospores are seen in Coccidioidomycosis, broad-based budding yeasts in Blastomycosis, and encapsulated yeast cells in Cryptococcosis.

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 commonly found colonizing wounds and lesions, but it is not a fungus. Candida, Aspergillus, and Malassezia are fungi that can opportunistically colonize or infect compromised skin or other lesions.

Question 22

Which statement regarding dermatophytosis is correct?

Accepted Answer

Dermatophytes are fungi that utilize keratin for growth. — Dermatophytes are a group of fungi that are capable of infecting keratinized tissues (skin, hair, nails) because they produce enzymes that break down keratin. While many dermatophytoses are treated with topical agents, extensive or stubborn infections often require systemic antifungal therapy.

Question 23

Which statement regarding laboratory identification of fungi is correct?

Accepted Answer

India ink stain is useful for visualizing the capsule of Cryptococcus neoformans. — An India ink stain can be used to visualize the characteristic capsule of Cryptococcus neoformans in cerebrospinal fluid or other clinical specimens. KOH mounts are used to dissolve keratin and visualize fungal elements. Gram stains are for bacteria. Sabouraud dextrose agar is a selective medium for fungal culture.

Question 24

All of the following are examples of superficial mycoses EXCEPT:

Accepted Answer

Aspergillosis — Pityriasis versicolor, Tinea pedis (athlete's foot), and Tinea nigra are all superficial mycoses affecting the stratum corneum or epidermis. Aspergillosis is typically considered a deep or systemic mycosis, although superficial forms can occur.

Question 25

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

Accepted Answer

Superficial dermatophytosis — Amphotericin B is a potent antifungal agent used for severe systemic fungal infections. Superficial dermatophytoses are typically treated with topical or oral agents that are less toxic and more targeted.

Question 26

A component of the cell membrane of most fungi is:

Accepted Answer

Ergosterol — Ergosterol is the primary sterol found in the cell membranes of fungi, analogous to cholesterol in mammalian cell membranes. Many antifungal drugs target ergosterol synthesis or function.

Question 27

Which statement regarding dermatophytosis is correct?

Accepted Answer

Dermatophytes are fungi that utilize keratin for growth. — Dermatophytes are a group of fungi that are capable of infecting keratinized tissues (skin, hair, nails) because they produce enzymes that break down keratin. While many dermatophytoses are treated with topical agents, extensive or stubborn infections often require systemic antifungal therapy.

Question 28

Which statement regarding laboratory identification of fungi is correct?

Accepted Answer

India ink stain is useful for visualizing the capsule of Cryptococcus neoformans. — An India ink stain can be used to visualize the characteristic capsule of Cryptococcus neoformans in cerebrospinal fluid or other clinical specimens. KOH mounts are used to dissolve keratin and visualize fungal elements. Gram stains are for bacteria. Sabouraud dextrose agar is a selective medium for fungal culture.

Question 29

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

Accepted Answer

Aspergillus fumigatus — Aspergillus fumigatus is an opportunistic pathogen that causes aspergillosis, particularly in immunocompromised individuals. While the others can cause significant disease, they are often considered primary pathogens in certain contexts, though immunocompromise can increase susceptibility.

Question 30

Aspergillosis is recognized in tissue by the presence of:

Accepted Answer

Septate hyphae with acute-angle branching — Aspergillus species are characterized by septate hyphae that exhibit acute-angle (approximately 45-degree) branching. Spherules with endospores are seen in Coccidioidomycosis, broad-based budding yeasts in Blastomycosis, and encapsulated yeast cells in Cryptococcosis.

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

Staphylococcus aureus — Staphylococcus aureus is a bacterium commonly found colonizing wounds and lesions, but it is not a fungus. Candida, Aspergillus, and Malassezia are fungi that can opportunistically colonize or infect compromised skin or other lesions.

Question 32

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

Accepted Answer

It causes blastomycosis. — Cryptococcus neoformans causes cryptococcosis, not blastomycosis. Blastomycosis is caused by Blastomyces dermatitidis. C. neoformans is indeed a yeast with a prominent polysaccharide capsule, found in bird droppings, and can cause severe meningoencephalitis.

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 dimorphic in the classical sense of exhibiting yeast and mold forms. It exists primarily as a yeast that can form pseudohyphae and true hyphae under certain conditions. It is a common commensal and opportunistic pathogen.

Question 34

Natural habitat for Paracoccidioides brasiliensis is:

Accepted Answer

Soil in endemic areas — Paracoccidioides brasiliensis is found in soil in endemic regions of Latin America. Inhalation of spores from this soil leads to infection.

Question 35

Coccidioidomycosis is also called:

Accepted Answer

All of the above — Coccidioidomycosis is known by several names, including Valley Fever and San Joaquin Valley Fever, due to its endemicity in these regions. 'Desert rheumatism' is also a term used to describe some of its more systemic manifestations.

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 common mycotoxins that contaminate nuts, grains, and other foodstuffs, and are potent carcinogens.

Weekly Year 3: Medical Mycology Exam - October 2, 2026 (S...

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