NEET-PG 2017 - Microbiology Practice Questions

Q: Which of the following diseases is caused by the virus shown below?

Aplastic crisis. ***Aplastic crisis*** - The image depicts a **bun-shaped, non-enveloped virus** with a **single-stranded DNA genome**, characteristic of **Parvovirus B19**. - **Parvovirus B19** has a strong tropism for **erythroid progenitor cells** in the bone marrow, leading to their lysis and subsequent inhibition of erythropoiesis, which can cause **aplastic crisis**, especially in individuals with underlying hemolytic disorders like sickle cell anemia. *Burkitt lymphoma* - This lymphoma is caused by **Epstein-Barr virus (EBV)**, a **double-stranded DNA herpesvirus**, which has a different morphology than the virus depicted. - EBV is associated with B-cell proliferation, not direct destruction of erythroid precursors which leads to aplastic crises. *Primary effusion lymphoma* - This is a rare B-cell lymphoma associated with **Human Herpesvirus 8 (HHV-8)**, also known as Kaposi's sarcoma-associated herpesvirus. - HHV-8 is a **double-stranded DNA virus** with a different structure and tropism than the parvovirus shown in the image. *Vesicular vaccination lesion* - Vesicular vaccination lesions are typically caused by the **Vaccinia virus**, a **large, complex DNA virus** belonging to the Poxviridae family. - The Vaccinia virus has a distinct brick-shaped morphology and replicates in the cytoplasm, unlike the small, non-enveloped parvovirus shown.

Q: Which of the following diseases is caused by the virus shown below?

Swimming pool conjunctivitis. ***Swimming pool conjunctivitis*** - The image displays an **adenovirus**, characterized by its **icosahedral shape** and distinct **fiber proteins** projecting from the vertices. - Adenoviruses are a common cause of **pharyngoconjunctival fever**, often referred to as "swimming pool conjunctivitis" due to its spread in **inadequately chlorinated swimming pools**. - This is the **most characteristic disease** associated with adenovirus infection, particularly serotypes **3, 4, and 7**. *Neurodegenerative disorder* - Adenoviruses are **not associated** with neurodegenerative disorders. - Neurodegenerative conditions are typically linked to **prions, misfolded proteins**, or other viral agents like **JC virus** (progressive multifocal leukoencephalopathy). - Adenoviruses cause **acute infections**, not chronic neurodegeneration. *Solid organ graft infection* - While adenoviruses can cause severe infections in **immunocompromised patients**, including transplant recipients, this is not their most characteristic presentation. - In transplant patients, adenovirus may cause **colitis, hepatitis, or nephritis**, but these are **opportunistic infections** rather than the typical disease association. - The characteristic disease remains **conjunctivitis and respiratory infections** in immunocompetent hosts. *Solid organ graft rejection* - **Graft rejection** is an **immunological process** where the recipient's immune system attacks the transplanted organ, not a viral infection. - Adenovirus does not directly cause the mechanism of graft rejection. - While viral infections may complicate graft outcomes, rejection itself is **immune-mediated**, not infectious.

Q: A 2-year-old unimmunized child from a village presents with fever, decreased feeding and ear ache. All are true about the virus responsible for the condition shown except: (Recent NEET Pattern 2016-17)

Belongs to genus morbillivirus. The image shows a child with characteristic swelling of the parotid gland, indicative of Mumps. The clinical presentation (unimmunized child, fever, decreased feeding, ear ache, and parotid swelling) strongly points to Mumps. ***Correct Answer: Belongs to genus morbillivirus*** - This statement is **FALSE** and therefore the correct answer to this "EXCEPT" question. - The virus responsible for Mumps is the **Mumps virus**, which belongs to the **genus Rubulavirus** within the family Paramyxoviridae, NOT Morbillivirus. - Morbillivirus is the genus to which the **Measles virus** belongs. *Incorrect: Nonsuppurative parotitis* - **TRUE statement** - Mumps is classically characterized by **nonsuppurative parotitis**, meaning inflammation of the salivary glands (primarily parotid) without pus formation. - This is a key diagnostic feature of Mumps. *Incorrect: Can lead to aseptic meningitis* - **TRUE statement** - Aseptic meningitis is one of the most common and significant complications of Mumps, occurring in 10-15% of cases. - This complication typically presents with headache, stiff neck, and photophobia, without bacterial infection. *Incorrect: Causative virus possesses both H and N proteins* - **TRUE statement** - The Mumps virus, a member of the Paramyxoviridae family, possesses a combined **HN (hemagglutinin-neuraminidase) protein** on its surface. - The HN protein has both hemagglutinin and neuraminidase activities, responsible for binding to host cells and facilitating release of new virions from infected cells.

Q: A 40-year-old AIDS positive patient complains of seeing floaters followed by progressive reduction in visual acuity over next weeks. Fundus examination was performed. All are true about the causative agent except: (Recent NEET Pattern 2016-17)

Eosinophilic intranuclear inclusions. ***Eosinophilic intranuclear inclusions*** - The causative agent of **CMV retinitis** (Cytomegalovirus) typically forms **basophilic intranuclear inclusions** (owl's eye inclusions), not eosinophilic ones. - This statement is therefore incorrect regarding CMV. *Shed in semen* - **CMV** is commonly shed in various bodily fluids, including **semen**, urine, and saliva, contributing to its transmission. - This is a true characteristic of CMV. *Largest virus in human herpes virus* - **CMV** (Human herpesvirus 5) is indeed the **largest virus in the human herpesvirus family**, both in terms of genome size and virion size. - This is a true characteristic of CMV. *Leads to pizza pie retinopathy* - The classic description of **CMV retinitis** on fundus examination is often referred to as "**pizza pie retinopathy**" or "cottage cheese and ketchup" appearance, due to its characteristic retinal hemorrhages and white, necrotic areas. - This is a true clinical manifestation of CMV retinitis.

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.

Question 1

Which of the following diseases is caused by the virus shown below?

Accepted Answer

Aplastic crisis

Answer

Burkitt lymphoma

Answer

Primary effusion lymphoma

Answer

Vesicular vaccination lesion

Question 2

Which of the following diseases is caused by the virus shown below?

Accepted Answer

Swimming pool conjunctivitis

Answer

Neurodegenerative disorder

Answer

Solid organ graft infection

Answer

Solid organ graft rejection

Question 3

A 2-year-old unimmunized child from a village presents with fever, decreased feeding and ear ache. All are true about the virus responsible for the condition shown except: (Recent NEET Pattern 2016-17)

Accepted Answer

Belongs to genus morbillivirus

Answer

Nonsuppurative parotitis

Answer

Can lead to aseptic meningitis

Answer

Causative virus possesses both H and N proteins

Question 4

A 40-year-old AIDS positive patient complains of seeing floaters followed by progressive reduction in visual acuity over next weeks. Fundus examination was performed. All are true about the causative agent except: (Recent NEET Pattern 2016-17)

Accepted Answer

Eosinophilic intranuclear inclusions

Answer

Shed in semen

Answer

Largest virus in human herpes virus

Answer

Leads to pizza pie retinopathy

Question 5

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 6

Which of the following worms is shown in the specimen?

Accepted Answer

Ascaris lumbricoides

Answer

Trichinella

Answer

Wuchereria bancrofti

Answer

Trichuris trichiura

Question 7

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 8

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 9

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 10

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

NEET-PG 2017 — Microbiology