Mycology Practice Questions

Q: Which of the following is correct about the vegetative fungal spores?

A = Blastospores, B= Arthrospores, C= Chlamydospores. **A = Blastospores, B= Arthrospores, C= Chlamydospores** - Image A depicts **blastospores**, which are asexually produced spores formed by **budding** from a parent cell, giving them a distinct tear-drop or oval shape. - Image B illustrates **arthrospores**, which are formed by the **fragmentation** of a hyphal cell into barrel-shaped segments. - Image C shows **chlamydospores**, characterized by their **thick-walled**, resistant, and usually spherical or oval structure within a hypha. *A = Arthrospores, B= Blastospores, C= Chlamydospores* - This option incorrectly identifies image A as arthrospores, which are typically barrel-shaped and result from hyphal fragmentation, not the budding pattern seen in image A. - Image B is incorrectly labeled as blastospores, but the fragmentation pattern is characteristic of arthrospores. *A = Blastospores, B= Chlamydospores, C= Arthrospores* - While image A is correctly identified as blastospores, this option misidentifies image B as chlamydospores. - Image C does not show arthrospores; the thick-walled structure is characteristic of chlamydospores, not the barrel-shaped arthrospores. *A = Chlamydospores, B= Arthrospores, C= Blastospores* - This option incorrectly identifies image A as chlamydospores, which are thick-walled resistant structures, not the budding spores visible in the image. - It also incorrectly labels image C as blastospores; the thick-walled appearance is typical of chlamydospores, not budded blastospores.

Q: All are correct about the organism causing the following lesion except:

Reynold Braude phenomenon. ***Reynold Braude phenomenon*** - The **Reynolds-Braude phenomenon** is associated with **Staphylococcus aureus** and refers to the increased invasiveness of *S. aureus* in the presence of certain other bacteria. - This phenomenon is **not characteristic of *Candida albicans***, the organism responsible for the oral candidiasis (thrush) shown in the image. - **This is the correct answer** to this "except" question. *Gram positive yeast cells* - *Candida albicans* is a **Gram-positive yeast** that appears purple/blue on Gram staining. - It typically shows **budding yeast cells** and **pseudohyphae** on microscopy. - This statement is TRUE for *Candida albicans*. *Chlamydospores obtained on cornmeal agar* - **Chlamydospores** are thick-walled, large, round terminal spores that are characteristic of *Candida albicans*. - They are best demonstrated on **cornmeal agar with Tween 80** (or rice agar), which is the standard medium for their production. - The presence of chlamydospores is a key identifying feature that helps differentiate *C. albicans* from other *Candida* species. - This statement is TRUE for *Candida albicans*. *Creamy patches that on removal lead to red oozing patches* - The image shows **creamy white patches** on an inflamed oral mucosa, characteristic of **pseudomembranous candidiasis** (oral thrush). - These patches can be **scraped off**, revealing an **erythematous, bleeding** (red oozing) underlying surface. - This is a classic clinical presentation of oral candidiasis. - This statement is TRUE for *Candida albicans*.

Q: All are correct about the image shown except:

Primary site of infection is CNS. ***Primary site of infection is CNS*** - While *Cryptococcus neoformans* is well-known for causing **meningitis** (a CNS infection), the **primary site of infection** is typically the **lungs**, acquired through inhalation of spores. Dissemination to the CNS occurs subsequently, especially in immunocompromised individuals. *Cryptococcus neoformans* - The image, showing encapsulated yeast cells with varying sizes and budding, is characteristic of **Cryptococcus neoformans** under India ink stain, where the capsule excludes the ink, creating a halo effect. - This fungus is known for its distinctive **thick polysaccharide capsule** and its tendency to be found in environments contaminated with bird droppings. *Thick polysaccharide capsule* - The clear halo around the yeast cells in the image directly demonstrates the presence of a **thick polysaccharide capsule**, which is a key virulence factor distinguishing *Cryptococcus neoformans*. - This capsule is responsible for the organism's unique appearance in **India ink preparations** and plays a crucial role in immune evasion. *Mucicarmine stain can be used* - The **mucicarmine stain** specifically stains the **polysaccharide capsule** of *Cryptococcus neoformans* bright red, aiding in its identification in tissue samples. - This stain is a valuable diagnostic tool, particularly when dealing with tissue biopsies where the capsule might not be as distinctly visible with India ink due to cellular debris.

Q: A patient walking barefoot during his morning walk has developed a swelling in the foot. What is the probable diagnosis?

Madura foot. **Madura foot (Correct Answer)** - **Madura foot**, or mycetoma, is a **chronic granulomatous infection** often acquired through minor skin trauma, such as walking barefoot on contaminated soil - Classic presentation: **localized swelling, draining sinuses, and grain formation** - The image shows a **swollen foot** with signs of chronic infection, consistent with the progressive nature of Madura foot affecting subcutaneous tissues and eventually bone - Endemic in tropical regions including India, making this the most likely diagnosis given barefoot walking *Staphylococcus aureus (Incorrect)* - While *S. aureus* can cause various skin infections and swelling, it typically presents with **acute infections** (abscesses, cellulitis, folliculitis) - A **chronic, localized swelling with potential sinus tracts** that progresses over time is less typical for uncomplicated *S. aureus* infections - The context of barefoot walking on soil is more suggestive of fungal or actinomycotic infections *Botryomycosis (Incorrect)* - **Botryomycosis** is a rare chronic bacterial infection that causes granulomas and abscesses, often with "grains" similar to mycetoma - Typically caused by bacteria like *Staphylococcus aureus* or *Pseudomonas aeruginosa*, **not typically acquired directly from soil** - Though it presents with granulomas and "grains," the context of walking barefoot and the endemic nature of mycetoma in India makes Madura foot more likely *Tetanus (Incorrect)* - **Tetanus** is a severe neurological condition caused by the toxin of *Clostridium tetani*, entering through wounds - Presents with **muscle spasms, rigidity, and lockjaw** (trismus) - Does **not cause localized swelling or chronic granulomatous lesions** as shown in the image - Wrong clinical presentation entirely

Q: A carpenter presents with a nodule on dorsum of hand which ulcerates after few days and has not healed for last 2 months. Biopsy of lesion was performed and shown below. Diagnosis is:

Sporotrichosis. ***Sporotrichosis*** - The image shows **cigar-shaped yeast cells** (arrow), characteristic of *Sporothrix schenckii*, the causative agent of sporotrichosis. The presence of an **asteroid body** (asterisk) formed by eosinophilic material radiating from the yeast cell is also classic for sporotrichosis in tissue. - The history of a **carpenter** presenting with a nodule that ulcerates after trauma (e.g., from wood splinters) and doesn't heal is highly suggestive of **sporotrichosis**, often referred to as "rose gardener's disease" due to occupational exposure. *Chromomycosis* - Characterized by the presence of **sclerotic bodies** (also known as Medlar bodies or fumagoid bodies) which are darkly pigmented, thick-walled, round cells that divide by septation. - The clinical presentation is typically slow-growing, **verrucous plaques** or nodules, predominantly on the lower extremities, which are distinct from the ulcerating nodule seen here. *Lobomycosis* - Caused by *Lacazia loboi*, it presents with **chains of yeast cells** that are spherical or ovoid, thick-walled, and interconnected by short tubes. - Clinically, it typically manifests as **keloid-like lesions** or chronic nodular plaques, primarily in tropical and subtropical regions, and does not commonly ulcerate in the initial presentation like the case described. *Cutaneous histoplasmosis* - Caused by *Histoplasma capsulatum*, which appears as **small, oval yeast cells** (2-4 µm) within macrophages in tissue sections. - While it can manifest cutaneously, especially in immunocompromised individuals, the yeast cells are much smaller and do not have the distinct cigar-shape or form asteroid bodies seen in the image.

Q: A 25-year-old truck driver presents with history of fever for 3 days with altered sensorium for 1 day. On the way to hospital he had an episode of vomiting followed by seizures. On examination reflexes are brisk and neck stiffness was noted. Mannitol was given and Lumbar puncture was performed. The microscopic examination of CSF sample yields the view given below. What is the diagnosis?

Cryptococcus. ***Cryptococcus*** - The image provided depicts an **India ink stain** of CSF, which is characteristic for visualizing the large polysaccharide **capsule** of *Cryptococcus neoformans* as a **clear halo** against a dark background. - Clinical features of fever, altered sensorium, seizures, brisk reflexes, and **neck stiffness** are consistent with meningitis, and *Cryptococcus* is a common cause, particularly in immunocompromised individuals or those with environmental exposure (like a truck driver who might be exposed to bird droppings). *Pneumococcus* - *Streptococcus pneumoniae* (Pneumococcus) is a common cause of bacterial meningitis, but it is a **bacterium, not a fungus**, and would not show a distinct capsule with India ink stain. - Microscopic examination of CSF for Pneumococcus would typically reveal **Gram-positive diplococci**, not encapsulated yeast forms. *Enterococcus* - *Enterococcus* species are **Gram-positive cocci** that can cause meningitis, especially in neonates, the elderly, or hospitalized patients, but they are also **bacteria**. - They also would not present with a capsule visible by India ink staining; routine Gram stain would be used for their identification. *Listeria monocytogenes* - *Listeria monocytogenes* is a **Gram-positive rod** that causes meningitis, particularly in pregnant women, neonates, the elderly, and immunocompromised individuals. - Similar to the other bacterial options, it is identified by **Gram stain** and culture, and an India ink stain would not reveal encapsulated yeast.

Q: Identify the fungal organism in this slide stained with Gomori-methenamine silver stain. (AIIMS Nov 2017)

Acute angle branching, aspergillus. **Acute angle branching, aspergillus** - The image shows **septate hyphae** with **acute angle (45-degree) branching**, which is characteristic of *Aspergillus* species. - While *Aspergillus* can be identified by conidial heads in culture, in tissue sections stained with Gomori-methenamine silver (GMS) stain, these morphological features are key. *Acute angle branching, rhizopus* - **Rhizopus** species typically exhibit **non-septate or sparsely septate hyphae** with **irregular branching**, often at wide angles. - This morphology differs from the regularly septate, acutely branching hyphae seen in the image. *Right angle branching, aspergillus* - **Aspergillus** hyphae characteristically show **acute angle (45-degree) branching**, not right-angle branching. - The hyphae are also **septate**, a feature that is clearly visible in the image. *Right angle branching, mucor* - **Mucor** species, like other Mucorales (e.g., *Rhizopus*, *Lichtheimia*), are known for their **non-septate or sparsely septate hyphae** with **wide-angle (often right-angle) branching**. - The hyphae in the image are clearly septate and branch acutely, ruling out *Mucor*.

Q: A young male presents with the following itchy lesion for one month. All of the following genera can cause this kind of lesion except:

Aspergillus. ***Aspergillus*** - **Aspergillus** species are opportunistic fungi that primarily cause **invasive aspergillosis** in immunocompromised patients, affecting lungs and sinuses rather than superficial skin infections. - Unlike dermatophytes, **Aspergillus** does not commonly cause **tinea (ringworm)** infections or the characteristic **annular, itchy lesions** seen in healthy individuals. *Trichophyton* - **Trichophyton** is a major dermatophyte genus causing various forms of **tinea**, including **tinea corporis**, which presents as itchy, ring-like lesions with central clearing. - This genus is responsible for **athlete's foot (tinea pedis)** and **jock itch (tinea cruris)**, commonly producing the scaly, erythematous lesions described. *Microsporum* - **Microsporum** is another important dermatophyte genus that causes **tinea corporis** and **tinea capitis**, manifesting as circular, itchy, scaling patches. - Infections by **Microsporum** typically show **well-demarcated borders** with central clearing, matching the clinical presentation of the described lesion. *Epidermophyton* - **Epidermophyton floccosum** is a dermatophyte that commonly causes **tinea cruris** and **tinea corporis**, producing characteristic **annular, pruritic lesions**. - While it cannot infect hair (no **tinea capitis**), it readily causes **superficial skin infections** with the typical ring-like appearance and scaling borders.

Q: The given KOH mount of a patient shows:

Budding yeasts and pseudohyphae. ***Budding yeasts and pseudohyphae*** - The image clearly displays structures characteristic of **budding yeast cells** and elongated forms consistent with **pseudohyphae**, which are typical findings in candidiasis. - This morphology is a hallmark of *Candida* species, commonly seen in KOH mounts from samples like vaginal swabs or skin scrapings for diagnosing fungal infections. *Spaghetti and meat ball appearance* - This description refers to the characteristic appearance of *Malassezia furfur* in KOH preparations, associated with **tinea versicolor**, showing short, curved hyphae and spherical yeast forms. - The image provided does not show the distinctive short, curved hyphae and clusters of yeast cells indicative of **Spaghetti and meat ball appearance**. *Clusters of pigmented cells* - This description would suggest the presence of **melanocytes** or possibly **pigmented fungi** (phaeohyphomycosis), which can be seen in certain fungal infections but are not what is depicted here. - The structures in the image appear to be fungal elements and are not distinctly pigmented cells formed in clusters. *Septate hyphae* - **Septate hyphae** are long, filamentous structures with regular cross-walls, characteristic of dermatophytes like *Trichophyton* or *Microsporum* species, causing ringworm. - While there are filamentous structures, they are primarily **pseudohyphae** (constricted at the septa, resembling a chain of elongated budding cells) rather than true septate hyphae, and are accompanied by distinct budding yeast forms.

Q: A patient has the following rash in the groin. Which of the following cannot be a cause?

Aspergillus. ***Aspergillus*** - **Aspergillus** is a **mold (filamentous fungus)**, NOT a dermatophyte, and therefore **cannot cause tinea cruris** (jock itch). - Dermatophytes (Trichophyton, Microsporum, Epidermophyton) are specialized fungi that digest keratin and cause superficial skin infections with characteristic ringworm patterns. - Aspergillus typically causes invasive infections in immunocompromised patients (invasive aspergillosis), allergic bronchopulmonary aspergillosis (ABPA), or rarely deep cutaneous infections in severely immunocompromised individuals—not superficial groin rashes. - **Key distinction:** Tinea cruris = dermatophyte infection; Aspergillus = opportunistic mold *Microsporum* - **Microsporum** species are dermatophytes that CAN cause tinea cruris, though less commonly than Trichophyton and Epidermophyton. - *M. canis* is the most common species, typically causing **tinea capitis** (scalp) and **tinea corporis** (body), but can extend to the groin area. - While not the most frequent cause, it remains a possible etiology and should not be excluded. *Epidermophyton* - **Epidermophyton floccosum** is one of the **most common causes** of tinea cruris. - Presents with itchy, erythematous, scaling patches with well-defined, elevated borders in the inguinal folds. - Thrives in warm, moist environments, making the groin an ideal location. - **Classic presentation:** bilateral involvement with central clearing and advancing scaly borders. *Trichophyton* - **Trichophyton rubrum** is the **MOST common** cause of tinea cruris worldwide, followed by **T. mentagrophytes**. - Causes characteristic pruritic, erythematous, annular or serpiginous lesions with raised, scaly borders. - T. rubrum accounts for the majority of dermatophyte infections in the groin, feet, and nails.

Question 1

Which of the following is correct about the vegetative fungal spores?

Accepted Answer

A = Blastospores, B= Arthrospores, C= Chlamydospores

Answer

A = Arthrospores, B= Blastospores, C= Chlamydospores

Answer

A = Blastospores, B= Chlamydospores, C= Arthrospores

Answer

A = Chlamydospores, B= Arthrospores, C= Blastospores

Question 2

All are correct about the organism causing the following lesion except:

Accepted Answer

Reynold Braude phenomenon

Answer

Gram positive yeast cells

Answer

Chlamydospores obtained on cornmeal agar

Answer

Creamy patches that on removal lead to red oozing patches

Question 3

All are correct about the image shown except:

Accepted Answer

Primary site of infection is CNS

Answer

Cryptococcus neoformans

Answer

Thick polysaccharide capsule

Answer

Mucicarmine stain can be used

Question 4

A patient walking barefoot during his morning walk has developed a swelling in the foot. What is the probable diagnosis?

Accepted Answer

Madura foot

Answer

Staphylococcus aureus

Answer

Botryomycosis

Answer

Tetanus

Question 5

A carpenter presents with a nodule on dorsum of hand which ulcerates after few days and has not healed for last 2 months. Biopsy of lesion was performed and shown below. Diagnosis is:

Accepted Answer

Sporotrichosis

Answer

Chromomycosis

Answer

Lobomycosis

Answer

Cutaneous histoplasmosis

Question 6

A 25-year-old truck driver presents with history of fever for 3 days with altered sensorium for 1 day. On the way to hospital he had an episode of vomiting followed by seizures. On examination reflexes are brisk and neck stiffness was noted. Mannitol was given and Lumbar puncture was performed. The microscopic examination of CSF sample yields the view given below. What is the diagnosis?

Accepted Answer

Cryptococcus

Answer

Pneumococcus

Answer

Enterococcus

Answer

Listeria monocytogenes

Question 7

Identify the fungal organism in this slide stained with Gomori-methenamine silver stain. (AIIMS Nov 2017)

Accepted Answer

Acute angle branching, aspergillus

Answer

Acute angle branching, rhizopus

Answer

Right angle branching, aspergillus

Answer

Right angle branching, mucor

Question 8

A young male presents with the following itchy lesion for one month. All of the following genera can cause this kind of lesion except:

Accepted Answer

Aspergillus

Answer

Trichophyton

Answer

Microsporum

Answer

Epidermophyton

Question 9

The given KOH mount of a patient shows:

Accepted Answer

Budding yeasts and pseudohyphae

Answer

Spaghetti and meat ball appearance

Answer

Clusters of pigmented cells

Answer

Septate hyphae

Question 10

A patient has the following rash in the groin. Which of the following cannot be a cause?

Accepted Answer

Aspergillus

Answer

Microsporum

Answer

Epidermophyton

Answer

Trichophyton

Mycology — MCQs

Mycology — MCQs

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