NEET-PG 2017 Practice Questions

Q: A 15-year-old female presents with nasal obstruction and occasional profuse epistaxis for last 8 weeks. Nasal speculum view and histopathology of resected lesion is given. All are correct about the diagnosis except:

Best cultured on nasal inoculation in hamster. *Best cultured on nasal inoculation in hamster* - This statement is **incorrect** because *Rhinosporidium seeberi*, the causative agent of rhinosporidiosis (which is indicated by the images and clinical presentation), is an **uncultivable organism** in artificial media or animal models. - Its complex life cycle and specific host requirements make *in vitro* or *in vivo* culture challenging and largely unsuccessful. *Multiple fungal spherules embedded in stroma of connective tissue* - The histopathology image clearly shows characteristic **spherules** of varying sizes, containing numerous endospores, embedded within the connective tissue stroma, which is typical for rhinosporidiosis. - These spherules represent different stages of the organism's life cycle. *Infection originates from stagnant water* - *Rhinosporidium seeberi* is commonly found in **stagnant water** (rivers, ponds) and is often associated with swimming, bathing, or working in such environments. - Exposure to contaminated water is the primary mode of transmission for this rare chronic granulomatous disease. *Surgical excision is best treatment* - **Surgical excision** of the mass with electrocoagulation of the base is considered the most effective treatment for rhinosporidiosis to prevent recurrence. - Anti-fungal medications like dapsone may be used as an adjunct to reduce recurrence rates.

Q: Which of the following eggs is seen in stool microscope examination?

Trichuris trichiura. ***Trichuris trichiura (whipworm) egg*** - The image displays a **barrel-shaped egg** with prominent, translucent **polar plugs (mucous plugs)** at each end, which is characteristic of *Trichuris trichiura* (whipworm) - These eggs measure approximately **50-54 × 22-23 μm** and have a thick, smooth shell with characteristic bipolar plugs - Found in **stool samples** during microscopic examination, indicating whipworm infection *Ascaris lumbricoides* - Eggs are **oval/round** (45-75 × 35-50 μm), not barrel-shaped - Have a thick, mammillated (bumpy) outer coat when unfertilized, or smooth when fertilized - **No polar plugs** - this is the key differentiating feature *Enterobius vermicularis* - Eggs are **asymmetrically oval** and flattened on one side (50-60 × 20-30 μm) - **No polar plugs** present - Rarely seen in stool; best detected by **perianal scotch tape test** *Taenia species* - Eggs are **spherical** (30-40 μm diameter) with radial striations - Contain a **six-hooked embryo (hexacanth)** inside - **No polar plugs** and completely different morphology

Q: Which of the following worms is shown in the specimen?

Ascaris lumbricoides. ***Ascaris lumbricoides*** - The image displays a collection of **large, creamy-white to yellowish-brown, roundworms** that are characteristic of *Ascaris lumbricoides*. These worms are often referred to as **giant roundworms** due to their size. - They are typically found in the **intestines** and can grow up to 35 cm in length, which is consistent with the appearance of the worms in the specimen jar. *Trichinella* - *Trichinella* species are **much smaller** and are typically not visible as macroscopic worms in a specimen jar in this manner. - They are primarily known for causing **trichinellosis**, where larvae encyst in muscle tissue, rather than forming large masses in the intestines. *Wuchereria bancrofti* - *Wuchereria bancrofti* causes **lymphatic filariasis** and its adult worms reside in the lymphatic system. - These worms are **thin and thread-like** and are generally much smaller and more delicate than the worms shown in the specimen, which appear robust. *Trichuris trichiura* - *Trichuris trichiura*, also known as **whipworm**, has a characteristic **whip-like appearance** with a thin anterior portion and a thicker posterior end. - While they are intestinal nematodes, they are generally **smaller** and have a distinct morphology not seen in the specimen.

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: 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 true about the terminal area marked 'X' in this bacteria except:

Strongly eosinophilic. ***Strongly eosinophilic*** - The terminal areas marked 'X' represent **metachromatic granules** (also called volutin granules) which stain reddish-purple with methylene blue, a basic dye, indicating they are **basophilic**, not eosinophilic. - Eosinophilic structures stain well with acidic dyes like eosin, resulting in a pink or red color. *Volutin granules* - The terminal areas marked 'X' are characteristic **volutin granules**, also known as **metachromatic granules**, which are inclusions seen in certain bacteria. - These granules are prominent in *Corynebacterium diphtheriae*, which typically exhibits a **club-shaped** or **cuneiform** morphology. *Function as storage reservoir for phosphate* - Volutin granules primarily serve as a **storage reservoir for inorganic polyphosphate**, which is crucial for the bacterium's energy metabolism and various cellular processes. - This stored phosphate can be utilized when environmental phosphate levels are low. *Also found in Yersinia pestis* - **Bipolar staining**, which resembles prominent granules at the ends of the bacteria (similar to the appearance of volutin granules), is a characteristic feature of *Yersinia pestis*. - This gives *Yersinia pestis* a distinctive "safety pin" appearance on Wright-Giemsa or Wayson stain.

Q: Which of the following bacteria will have following appearance?

Alcaligenes faecalis. ***Alcaligenes faecalis*** - The image shown is a **rod-shaped bacterium** with a **tuft of flagella at each pole**, resulting in a **bipolar flagellation** pattern typical of *Alcaligenes faecalis*. - This arrangement of flagella (amphitrichous) is characteristic for motility in this specific bacterium. *Vibrio cholerae* - *Vibrio cholerae* is a **curved rod** (comma-shaped) and typically possesses a **single polar flagellum** (monotrichous), which is different from the structure shown. - Its unique shape and flagellar arrangement are key identifiers in microbiology. *Spirilla* - **Spirilla** are **spiral-shaped bacteria** with a rigid, wavy form, which is distinctly different from the rod shape depicted in the image. - They can have various flagellar arrangements, but their overall morphology is elongated and coiled, not straight. *Salmonella typhi* - *Salmonella typhi* is a **rod-shaped bacterium** but it is typically **peritrichous**, meaning it has flagella distributed all over its cell surface, not just at the poles. - The image clearly shows flagella only at the ends, ruling out *Salmonella typhi*.

Q: A 25-year-old abattoir worker presents with myoclonus and amnesia for recent and remote events for last 1 year. MRI head was performed. All statements are correct about the organisms leading to this disease except:

Sensitive to ethylene dioxide. ***Sensitive to ethylene dioxide*** - Prions, the causative agents of Creutzfeldt-Jakob Disease (CJD), are **resistant to conventional sterilization methods**, including ethylene oxide, radiation, and disinfectants like formaldehyde. This statement is incorrect. - They are primarily inactivated by methods that denature proteins, such as **autoclaving at high temperatures and pressures** or strong sodium hydroxide solutions. *Absence of nucleic acid* - **Prions are infectious proteinaceous particles** that lack nucleic acid (DNA or RNA), which distinguishes them from viruses, bacteria, and other conventional pathogens. - They propagate by inducing conformational changes in normal host proteins. *CSF examination of patient shows presence of protein 14.3.3* - The presence of **14-3-3 protein** in cerebrospinal fluid (CSF) is a significant and widely used diagnostic marker for **Creutzfeldt-Jakob Disease (CJD)**. - Elevated levels of this protein indicate neuronal damage and are often found in patients with rapidly progressive dementia caused by prions. *MRI shows cortical ribboning* - **Cortical ribboning**, characterized by hyperintense signal changes in the cerebral cortex on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences, is a **highly characteristic finding in MRI scans of patients with CJD**. - This MRI finding, along with involvement of the basal ganglia and thalamus, supports the diagnosis of CJD.

Q: The image shows:

Loeffler serum slope. ***Loeffler serum slope*** - This image shows a **Loeffler serum slope**, characterized by its **pale yellow, solidified appearance** in a test tube, often used for culturing *Corynebacterium diphtheriae*. - The medium provides various nutrients and typically encourages the rapid growth of diphtheria bacilli, producing **characteristic morphology**. *Lowenstein Jensen media* - **Lowenstein Jensen media** is typically **greenish** due to the presence of **malachite green**, which inhibits the growth of most contaminants. - It is primarily used for the cultivation of **mycobacteria**, particularly *Mycobacterium tuberculosis*. *Wilson-Blair medium* - **Wilson-Blair medium** is a classic selective medium used for the isolation of *Salmonella typhi* and other *Salmonella* species, appearing as **black colonies**. - This medium contains **bismuth sulfite**, which imparts a distinctive black color to the colonies due to hydrogen sulfide production. *Selenite F broth* - **Selenite F broth** is a **clear enrichment broth** used for the isolation of *Salmonella* and *Shigella* species from fecal samples. - It works by **inhibiting the growth of coliforms** while allowing *Salmonella* and *Shigella* to multiply.

Question 1

A 15-year-old female presents with nasal obstruction and occasional profuse epistaxis for last 8 weeks. Nasal speculum view and histopathology of resected lesion is given. All are correct about the diagnosis except:

Accepted Answer

Best cultured on nasal inoculation in hamster

Answer

Multiple fungal spherules embedded in stroma of connective tissue

Answer

Infection originates from stagnant water

Answer

Surgical excision is best treatment

Question 2

Which of the following eggs is seen in stool microscope examination?

Accepted Answer

Trichuris trichiura

Answer

Taenia species

Answer

Ascaris lumbricoides

Answer

Enterobius vermicularis

Question 3

Which of the following worms is shown in the specimen?

Accepted Answer

Ascaris lumbricoides

Answer

Trichinella

Answer

Wuchereria bancrofti

Answer

Trichuris trichiura

Question 4

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 5

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 6

All are true about the terminal area marked 'X' in this bacteria except:

Accepted Answer

Strongly eosinophilic

Answer

Volutin granules

Answer

Function as storage reservoir for phosphate

Answer

Also found in Yersinia pestis

Question 7

Which of the following is correct about the image shown?

Accepted Answer

A = Monotrichous, B = Lophotrichous, C = Amphitrichous, D = Peritrichous

Answer

A = Lophotrichous, B = Monotrichous, C = Amphitrichous, D = Peritrichous

Answer

A = Monotrichous, B = Lophotrichous, C = Peritrichous, D = Amphitrichous

Answer

A = Peritrichous, B = Lophotrichous, C = Amphitrichous, D = Monotrichous

Question 8

Which of the following bacteria will have following appearance?

Accepted Answer

Alcaligenes faecalis

Answer

Vibrio cholerae

Answer

Spirilla

Answer

Salmonella typhi

Question 9

A 25-year-old abattoir worker presents with myoclonus and amnesia for recent and remote events for last 1 year. MRI head was performed. All statements are correct about the organisms leading to this disease except:

Accepted Answer

Sensitive to ethylene dioxide

Answer

Absence of nucleic acid

Answer

CSF examination of patient shows presence of protein 14.3.3

Answer

MRI shows cortical ribboning

Question 10

The image shows:

Accepted Answer

Loeffler serum slope

Answer

Lowenstein Jensen media

Answer

Wilson-Blair medium

Answer

Selenite F broth

NEET-PG 2017

ENT

Microbiology