FMGE 2019 - Microbiology PYQs Practice Questions

Q: A bacterium that can thrive at temperatures around 60-70 degrees Celsius is classified as

Thermophilic. ***Thermophilic*** - **Thermophilic** bacteria are heat-loving organisms that thrive at high temperatures, typically in the range of **45°C to 80°C**, with optimal growth around 50-70°C - These organisms are commonly found in hot springs, compost heaps, and industrial processes - **Note**: Extreme thermophiles (hyperthermophiles) can grow at temperatures exceeding 80-100°C, found in hydrothermal vents and geothermal environments *Mesophilic* - **Mesophilic** bacteria grow best at moderate temperatures, typically between **20°C and 45°C** - This includes most human pathogens and bacteria found in normal body temperature environments - These organisms cannot survive the high temperatures characteristic of thermophiles *Cryophilic* - **Cryophilic** (or psychrophilic) bacteria are cold-loving organisms that thrive at low temperatures, typically **below 20°C** - These organisms are adapted to cold environments like polar regions, deep oceans, and refrigerated foods - They would be rapidly killed at thermophilic temperature ranges *Halophilic* - **Halophilic** bacteria require high concentrations of salt (NaCl) for growth - This classification is based on **salt tolerance**, not temperature preference - Halophiles can be mesophilic, thermophilic, or psychrophilic depending on their temperature requirements [Practice more Microbiology PYQs on OnCourse]

Q: Which of the following viruses is from the Herpes virus family?

EBV. ***EBV*** - **Epstein-Barr Virus (EBV)** is a member of the **Herpesviridae** family, specifically **Human Herpesvirus 4 (HHV-4)**. - It is a **DNA virus** (double-stranded DNA), which is characteristic of all herpesviruses. - It is known to cause **infectious mononucleosis** and is associated with various malignancies. *Rubella* - **Rubella virus** belongs to the family **Togaviridae** and is the causative agent of **German measles**. - It is an **RNA virus** and is not classified within the Herpesviridae family. *Rabies* - **Rabies virus** is a member of the **Rhabdoviridae** family, specifically the genus **Lyssavirus**. - It is a neurotropic **RNA virus** causing a rapidly progressive, fatal encephalitis. *Measles* - **Measles virus**, also known as **Rubeola**, belongs to the family **Paramyxoviridae**. - It is an **RNA virus** responsible for a highly contagious airborne disease. [Practice more Microbiology PYQs on OnCourse]

Q: Increased susceptibility to N. meningitidis infections is associated with deficiency of which complement component:

C5-C9 deficiency. ***C5-C9 deficiency*** - Deficiencies in late complement components (C5-C9) prevent the formation of the **Membrane Attack Complex (MAC)**, which is essential for the lysis of **Neisseria species**. - This specific deficiency leads to an increased risk of recurrent, invasive infections with **Neisseria meningitidis** and **Neisseria gonorrhoeae**. *C1-C4 deficiency* - Deficiencies in early classical pathway components (C1, C2, C4) are most strongly associated with **systemic lupus erythematosus (SLE)** and other **immune complex disorders**. - While they increase the risk of pyogenic infections, they do not carry the same specific predilection for **Neisseria** as terminal pathway defects. *C3 deficiency* - **C3** is the central converging point for all complement pathways; its deficiency results in severe, recurrent infections with **encapsulated bacteria** (e.g., S. pneumoniae). - Deficiency impairs **opsonization** and recruitment of inflammatory cells, leading to a much broader spectrum of infectious susceptibility than MAC deficiency. *C2 deficiency* - **C2 deficiency** is the most common human complement deficiency and is frequently linked to **autoimmune diseases** like SLE due to poor immune complex clearance. - Although it can predispose individuals to infections by **encapsulated organisms**, it is not the classic association for isolated **meningococcal** susceptibility. [Practice more Microbiology PYQs on OnCourse]

Q: Molluscum contagiosum is caused by a:

Pox virus. ***Pox virus*** - **Molluscum contagiosum** is a common **cutaneous viral infection** caused by the **Molluscum Contagiosum Virus (MCV)**. - MCV belongs to the **Poxviridae family**, which are known for causing characteristic skin lesions. *Flavi virus* - **Flaviviruses** are a genus of RNA viruses, which cause diseases like **Dengue fever**, **Yellow fever**, and **Zika virus infection**. - They typically cause **systemic illnesses** with fever and rash, rather than localized skin lesions like molluscum contagiosum. *Adenovirus* - **Adenoviruses** are DNA viruses primarily associated with **respiratory infections** (e.g., common cold, bronchitis) and **conjunctivitis**. - They are not known to cause the characteristic **umbilicated papules** seen in molluscum contagiosum. *Rubivirus* - **Rubivirus** is a genus that includes the **Rubella virus**, which causes **German measles** (Rubella). - Rubella is characterized by a **maculopapular rash** and **lymphadenopathy**, which is distinct from the **umbilicated papules** seen in molluscum contagiosum. [Practice more Microbiology PYQs on OnCourse]

Q: Antemortem diagnosis of rabies is made with:

Corneal impression smear. ***Corneal impression smear*** - A **corneal impression smear** can detect viral antigens in the cornea using fluorescent antibody staining, a method that can be performed on living patients. - This technique provides a relatively rapid and non-invasive way to diagnose rabies **antemortem**. *Inoculation in culture media* - Rabies virus is notoriously difficult to culture in standard cell culture media, making this method impractical and unreliable for **antemortem diagnosis**. - While viral isolation is possible in specialized research settings, it is not a routine diagnostic tool for rabies in living patients. *Negri bodies in hippocampus* - **Negri bodies** are eosinophilic inclusions found in the cytoplasm of neurons, particularly in the hippocampus, which are pathognomonic for rabies. - However, their detection requires **postmortem brain tissue biopsy**, making this a **postmortem diagnostic** method, not antemortem. *Rabies virus specific antibodies* - While the presence of **rabies virus-specific antibodies** (particularly in CSF) can indicate exposure and infection, they often appear late in the disease course. - The detection of antibodies may not be reliable for early **antemortem diagnosis**, especially in naive individuals whose immune response has not yet fully developed. [Practice more Microbiology PYQs on OnCourse]

Question 1

A bacterium that can thrive at temperatures around 60-70 degrees Celsius is classified as

Accepted Answer

Thermophilic

Answer

Mesophilic

Answer

Cryophilic

Answer

Halophilic

Question 2

Which of the following viruses is from the Herpes virus family?

Accepted Answer

EBV

Answer

Rubella

Answer

Rabies

Answer

Measles

Question 3

Increased susceptibility to N. meningitidis infections is associated with deficiency of which complement component:

Accepted Answer

C5-C9 deficiency

Answer

C1-C4 deficiency

Answer

C3 deficiency

Answer

C2 deficiency

Question 4

Molluscum contagiosum is caused by a:

Accepted Answer

Pox virus

Answer

Flavi virus

Answer

Adenovirus

Answer

Rubivirus

Question 5

Antemortem diagnosis of rabies is made with:

Accepted Answer

Corneal impression smear

Answer

Inoculation in culture media

Answer

Negri bodies in hippocampus

Answer

Rabies virus specific antibodies

Question 6

EBV is most strongly associated with which of the following?

Accepted Answer

Nasopharyngeal carcinoma

Answer

Gastric cancer

Answer

Esophageal cancer

Answer

Hepatocellular carcinoma

Question 7

The following serological status is noted in a patient: HbsAg positive and HbeAg positive. Diagnosis is?

Accepted Answer

Active hepatitis B with high infectivity

Answer

Chronic viral hepatitis

Answer

Remote infection

Answer

Resolved hepatitis B infection

Question 8

What is the mode of transmission of genetic material to bacteria through bacteriophage?

Accepted Answer

Transduction

Answer

Transformation

Answer

Conjugation

Answer

Translation

Question 9

Chronic viral hepatitis is seen with all of the following viruses, except?

Accepted Answer

HEV

Answer

HCV

Answer

HBV

Answer

HDV

Question 10

A patient presented with some unknown fungal infection. Microscopic examination revealed brown coloured spherical fungi with septate hyphae. Possible condition:

Accepted Answer

Chromoblastomycosis

Answer

Histoplasmosis

Answer

Candida albicans

Answer

Coccidioidomycosis

FMGE 2019 — Microbiology