NEET-PG 2019 - Microbiology PYQs Practice Questions

Q: Rubella virus belongs to which family?

Togavirus. ***Togavirus*** - The **Rubella virus** is categorized under the family **Togaviridae**, specifically within the genus *Rubivirus*. - This classification is based on its genetic structure, being an **enveloped, positive-sense, single-stranded RNA virus**. *Rheovirus* - **Reoviruses** are characterized by a **double-stranded segmented RNA genome** and are typically non-enveloped. - This contrasts with Rubella's single-stranded, non-segmented RNA and enveloped structure. *Picornavirus* - **Picornaviruses** are a family of **non-enveloped, positive-sense, single-stranded RNA viruses** that are structurally different from Rubella. - Examples include species like **poliovirus** and **rhinovirus**, which do not share the distinct biological properties of Rubella. *Orthomyxovirus* - **Orthomyxoviruses** are a family of **enveloped, negative-sense, segmented RNA viruses**, which includes influenza viruses. - Their genomic organization and replication strategy are fundamentally different from those of the Rubella virus. [Practice more Microbiology PYQs on OnCourse]

Q: A 36-year-old male patient complaining of cough, cold, fever, and rusty sputum, with a history of travel to China and consumption of crab. Name the infection.

Paragonimus westermani. ***Paragonimus westermani*** - This patient's symptoms of **cough**, **fever**, and **rusty sputum**, combined with a history of **travel to China** and consumption of **crab**, are highly suggestive of **paragonimiasis**. - *Paragonimus westermani* is a **lung fluke** endemic to East Asia, and its larvae are acquired by ingesting undercooked **crabs** or **crayfish**. *Fasciola hepatica* - *Fasciola hepatica* causes **fascioliasis**, primarily affecting the **liver** and **biliary ducts**, leading to symptoms like **fever**, **abdominal pain**, and **hepatomegaly**. - It is acquired by consuming **contaminated watercress** or other aquatic plants, not crabs. *Fasciolopsis buski* - *Fasciolopsis buski* causes **fasciolopsiasis**, an **intestinal fluke infection** presenting with **abdominal pain**, **diarrhea**, and **malabsorption**. - It is transmitted through ingestion of **contaminated aquatic plants**, and does not typically cause respiratory symptoms or "rusty sputum." *Entamoeba histolytica* - *Entamoeba histolytica* is a **protozoan** that causes **amoebiasis**, primarily presenting as **dysentery** or **amoebic liver abscess**. - While it can manifest as fever and liver involvement, it does not cause respiratory symptoms like "rusty sputum" and is not acquired from crabs. [Practice more Microbiology PYQs on OnCourse]

Q: What is the gold standard microbiological test for diagnosing Leptospira infection?

Microscopic agglutination test (MAT). ***Microscopic agglutination test (MAT)*** - The **Microscopic Agglutination Test (MAT)** is considered the **gold standard** for diagnosing leptospirosis due to its high sensitivity and specificity. - It detects **agglutinating antibodies** against live leptospiral serovars, allowing for both diagnosis and serovar identification. *Cold agglutination* - **Cold agglutinins** are antibodies that react with red blood cells at cold temperatures and are typically associated with **Mycoplasma pneumoniae** infections or certain autoimmune conditions. - This test is **not used** for the diagnosis of leptospirosis. *Standard agglutination* - **Standard agglutination tests** involve macroscopic observation of agglutination and are generally less sensitive and specific than microscopic methods. - While agglutination is the principle, the **MAT** specifically refers to the microscopic, highly sensitive method used for Leptospira. *ELISA test* - **ELISA (Enzyme-Linked Immunosorbent Assay)** is used for leptospirosis, primarily for screening and detecting **IgM antibodies** in acute infections. - However, it has **lower specificity** and sensitivity compared to MAT, particularly in early stages or for serovar differentiation. [Practice more Microbiology PYQs on OnCourse]

Q: Which viral infection is known to cause a condition resembling erythroblastosis?

Parvovirus B19. ***Parvovirus B19*** - **Parvovirus B19** has a specific tropism for **erythroid progenitor cells** in the bone marrow. - In the fetus, congenital infection causes **severe anemia** due to destruction of red blood cell precursors, leading to **hydrops fetalis** with massive compensatory erythropoiesis. - This results in circulating **nucleated red blood cells (erythroblasts)**, hepatosplenomegaly from extramedullary hematopoiesis, and severe anemia - a picture closely **resembling erythroblastosis fetalis**. - Unlike the immune-mediated hemolysis in Rh isoimmunization, parvovirus causes direct viral destruction of erythroid precursors with similar clinical manifestations. *CMV* - **Cytomegalovirus (CMV)** is the most common congenital infection and can cause hepatosplenomegaly, jaundice, and thrombocytopenia. - However, CMV typically causes **direct hyperbilirubinemia** from hepatocellular damage rather than the hemolytic anemia pattern seen in erythroblastosis. - While CMV can affect hematopoiesis, it does not characteristically produce the massive erythroblast response and hydrops pattern typical of erythroblastosis fetalis. *EBV* - **Epstein-Barr virus (EBV)** primarily causes **infectious mononucleosis** in older children and adults, with atypical lymphocytosis. - EBV is rare in neonates and does not cause fetal hydrops or an erythroblastosis-like syndrome. - Associated with lymphoproliferative disorders and post-transplant complications rather than fetal anemia. *HSV* - **Herpes simplex virus (HSV)** causes disseminated neonatal infection with encephalitis, hepatitis, and mucocutaneous lesions. - HSV does not have tropism for erythroid precursors and does not cause the anemia, hydrops, or erythroblastosis-like picture. - Typically acquired perinatally rather than causing congenital infection with hematologic manifestations. [Practice more Microbiology PYQs on OnCourse]

Q: Which culture media is specifically used for the growth of Legionella?

Buffered Charcoal Yeast Extract (BCYE) agar. ***(BCYE) agar media*** - **Buffered charcoal yeast extract (BCYE) agar** is the specific and most widely used culture medium for the isolation and growth of *Legionella* species. - It contains **L-cysteine** and **iron salts**, which are essential growth factors for *Legionella*, along with activated charcoal to neutralize toxic metabolites. *MacConkey agar* - **MacConkey agar** is a selective and differential medium primarily used for the isolation of **Gram-negative enteric bacilli**. - It inhibits the growth of Gram-positive bacteria and differentiates lactose fermenters from non-fermenters. *Baird–Parker agar* - **Baird–Parker agar** is a selective medium specifically designed for the isolation and enumeration of **coagulase-positive staphylococci**, particularly *Staphylococcus aureus*, from food and clinical samples. - It contains tellurite, which is reduced by staphylococci to form black colonies. *Sabouraud’s agar* - **Sabouraud's dextrose agar (SDA)** is a selective medium primarily used for the cultivation of **fungi** (yeasts and molds). - Its low pH and high dextrose concentration inhibit the growth of most bacteria. [Practice more Microbiology PYQs on OnCourse]

Question 1

Rubella virus belongs to which family?

Accepted Answer

Togavirus

Answer

Orthomyxovirus

Answer

Rheovirus

Answer

Picornavirus

Question 2

A 36-year-old male patient complaining of cough, cold, fever, and rusty sputum, with a history of travel to China and consumption of crab. Name the infection.

Accepted Answer

Paragonimus westermani

Answer

Fasciola hepatica

Answer

Fasciolopsis buski

Answer

Entamoeba histolytica

Question 3

What is the gold standard microbiological test for diagnosing Leptospira infection?

Accepted Answer

Microscopic agglutination test (MAT)

Answer

Cold agglutination

Answer

Standard agglutination

Answer

ELISA test

Question 4

Which viral infection is known to cause a condition resembling erythroblastosis?

Accepted Answer

Parvovirus B19

Answer

EBV

Answer

CMV

Answer

HSV

Question 5

Which culture media is specifically used for the growth of Legionella?

Accepted Answer

Buffered Charcoal Yeast Extract (BCYE) agar

Answer

MacConkey agar

Answer

Baird–Parker agar

Answer

Sabouraud’s agar

Question 6

What is the causative organism for the condition depicted in the image?

Accepted Answer

Staphylococci

Answer

Candidal infection

Answer

Streptococcus

Answer

Actinomycetes

Question 7

Green frothy vaginal discharge is produced by –

Accepted Answer

Trichomonas vaginalis

Answer

Herpes simplex

Answer

Candida albicans

Answer

Normal vaginal flora

Question 8

A 6-year-old boy presents with fever and chills, cough, rapid breathing, difficulty breathing, and chest pain. A culture from a respiratory sample shows Gram-positive bacteria. What is the most likely organism causing this infection?

Accepted Answer

Streptococcus pneumoniae

Answer

Streptococcus pyogenes

Answer

Staphylococcus aureus

Answer

Propionibacterium acnes

Question 9

What is the primary method for diagnosing Pneumocystis jirovecii pneumonia?

Accepted Answer

Bronchoalveolar lavage (BAL)

Answer

Sputum microscopy

Answer

Chest X-ray findings

Answer

Serum beta-D-glucan assay

Question 10

MHC II is associated with:-

Accepted Answer

Antigen presenting cells

Answer

Red blood cells

Answer

Platelets

Answer

Epithelial cells

NEET-PG 2019 — Microbiology