NEET-PG 2013 - Microbiology Practice Questions

Q: Pseudomonas is which type of bacteria?

Aerobic. ***Aerobic*** - **Pseudomonas aeruginosa** is a classic example of an **aerobic bacterium**, meaning it requires oxygen for growth and metabolism. - Its ability to thrive in aerobic environments contributes to its prevalence in hospital settings and its capacity to cause a wide range of infections. *Anaerobic* - Anaerobic bacteria grow in the absence of oxygen and often die in its presence. **Pseudomonas** does not exhibit this characteristic. - Examples of anaerobic bacteria include *Clostridium* species. *Microaerophilic* - Microaerophilic bacteria require oxygen but only in low concentrations (5-10%), higher concentrations are inhibitory. - **Pseudomonas** grows optimally in atmospheric oxygen levels, not restricted to low concentrations. *Obligate anaerobe* - Obligate anaerobes are severely inhibited or killed by oxygen. - This is the opposite of **Pseudomonas**, which strictly requires oxygen for survival.

Q: Which of the following Chlamydia species is primarily associated with respiratory infections?

C pneumoniae. ***C pneumoniae*** - *C. pneumoniae* is the **primary Chlamydia species** associated with **respiratory infections** in humans - It is a common cause of **community-acquired pneumonia** (5-10% of cases), **atypical pneumonia**, **bronchitis**, **pharyngitis**, and **sinusitis** - Transmission occurs via **respiratory droplets** from person to person - Causes both **acute and chronic respiratory infections** and has been linked to exacerbations of asthma and COPD - It is the most frequently encountered Chlamydia species in respiratory tract infections *C psittaci* - Causes **psittacosis** (ornithosis), a specific type of **atypical pneumonia** transmitted from **birds** (parrots, pigeons, poultry) - While it does cause respiratory infection, it is much **less common** than C. pneumoniae and is associated with **occupational or recreational bird exposure** - Not the primary Chlamydia species for general respiratory infections *C trachomatis* - Primarily causes **genital tract infections** (urethritis, cervicitis, PID) and **ocular infections** (trachoma, inclusion conjunctivitis) - Can cause **neonatal pneumonia** in infants exposed during birth, presenting at 1-3 months of age with a staccato cough - NOT a primary respiratory pathogen in adults *None of the options* - This is incorrect because **C. pneumoniae** is definitively the Chlamydia species primarily associated with respiratory infections

Q: Which of the following statements about viruses is false?

Viruses are capable of independent motility.. ***Viruses are capable of independent motility.*** - Viruses are **acellular infectious agents** and lack the cellular machinery required for independent movement or motility. - They rely on host cell processes or environmental factors for their dissemination and entry into cells. *Viruses lack ribosomes.* - Viruses are **obligate intracellular parasites**; they lack ribosomes and other cellular organelles necessary for protein synthesis. - They hijack the host cell's ribosomes and metabolic machinery to replicate their genetic material and produce viral proteins. *Viruses lack mitochondria.* - Viruses lack mitochondria, as they are **not capable of generating their own ATP** through cellular respiration. - They depend on the host cell's energy-generating systems to provide the ATP required for their replication cycle. *Viruses contain nucleic acid.* - All viruses contain a **nucleic acid genome**, which can be either DNA or RNA. - This genetic material carries the instructions for viral replication and is enclosed within a protein coat called a **capsid**.

Q: Who discovered the bacterium Treponema pallidum?

Fritz Schaudinn and Erich Hoffmann. ***Fritz Schaudinn and Erich Hoffmann*** - **Fritz Schaudinn** was a German zoologist, and **Erich Hoffmann** was a German dermatologist; they jointly discovered **Treponema pallidum** in **1905**. - Their discovery of the spirochete was a crucial step in understanding the etiology of **syphilis**. *Robert Koch* - **Robert Koch** is renowned for identifying the causative agents of **tuberculosis**, **cholera**, and **anthrax**. - He developed Koch's postulates, a fundamental set of criteria for establishing the causal relationship between a microbe and a disease. *Twort* - **Frederick Twort** was a British bacteriologist who is credited with the discovery of **bacteriophages** in **1915**. - His work involved examining transparent areas in bacterial cultures, leading to the identification of lytic viruses that infect bacteria. *Ellerman* - **Vilhelm Ellerman** was a Danish pathologist known for his work in **hematology** and **virology**. - Alongside **Olaf Bang**, he demonstrated that avian leukemia (erythroleukemia) could be transmitted by a filterable agent, indicating a viral etiology for some cancers.

Q: An adolescent male developed vomiting and diarrhea 1 hour after having food from a restaurant. The most likely pathogen is?

Staphylococcus aureus. ***Staphylococcus aureus*** - The rapid onset of symptoms (within 1 hour) strongly suggests **pre-formed toxin ingestion**, which is characteristic of *Staphylococcus aureus* food poisoning. - While the typical incubation period is **1-6 hours** (average 2-4 hours), onset within 1 hour can occur with **high toxin loads** in contaminated food. - **Vomiting** is often the predominant symptom, occurring shortly after consuming contaminated food, which distinguishes it from other bacterial causes. *Clostridium perfringens* - Onset of symptoms caused by *Clostridium perfringens* is typically **8-16 hours** after ingestion, which is much longer than observed here. - It primarily causes **diarrhea and abdominal cramps** due to toxin production in the intestine, with minimal vomiting. *Vibrio parahaemolyticus* - Symptoms usually appear **4-96 hours** (average 12-24 hours) after consuming contaminated seafood, which is a longer incubation period than described. - It typically causes **watery diarrhea**, abdominal cramps, nausea, and occasional vomiting, but not within 1 hour. *Salmonella* - The incubation period for *Salmonella* infection is typically **6-72 hours** (average 12-36 hours), making it highly unlikely for symptoms to appear within 1 hour. - **Diarrhea, fever, and abdominal cramps** are common with *Salmonella*, but rapid-onset vomiting from pre-formed toxin is not its mechanism.

Q: Cylindrical helminths are -

Roundworms. ***Roundworms*** - **Roundworms**, also known as **nematodes**, are characterized by their **cylindrical body shape**. - Their unsegmented, tapered bodies distinguish them from flatworms like tapeworms and flukes. *Tapeworms* - **Tapeworms**, or **cestodes**, have **flat, ribbon-like bodies** segmented into proglottids. - They are not cylindrical but rather dorsoventrally flattened. *Flukes* - **Flukes**, or **trematodes**, have **flat, leaf-shaped bodies**, which are not cylindrical. - Their morphology includes suckers for attachment and they are not segmented. *Hookworms* - **Hookworms** are a type of **roundworm** (nematode), which means they are cylindrical. However, "Roundworms" is a broader and more accurate classification for the general term "cylindrical helminths." - While hookworms are indeed cylindrical, the option "Roundworms" encompasses all such cylindrical helminths, making it a more general and appropriate answer.

Q: Most common site for hydatid cyst

Liver. ***Liver*** - The **liver** is the most common site for hydatid cysts, accounting for approximately **60-70%** of cases [1]. - It often leads to **biliary obstruction** and liver dysfunction, highlighting its impact on the organ. *Kidney* - Hydatid cysts in the **kidney** are rare and account for a small percentage of cases (around **2-5%**). - Symptoms are often nonspecific, including **flank pain** or hematuria, which are not primary concerns. *Brain* - While the **brain** can be affected, it is not a common site; CNS involvement occurs in only **1-2%** of hydatid disease cases. - Symptoms are related to increased intracranial pressure or focal neurological deficits, not typical for hydatid cysts. *Lung* - The **lung** is another site for hydatid cysts but accounts for about **10-20%** of cases. - Presentation may include **cough** and chest pain, making it less common compared to liver involvement.

Q: Vaccines are available against which types of meningococcus?

Type A, B, C, W, and Y. ***Type A, B, C, W, and Y*** - Vaccines are currently available against **all five major meningococcal serogroups**: A, B, C, W-135, and Y. - **Meningococcal conjugate vaccines (MenACWY)** provide protection against serogroups A, C, W-135, and Y, and are widely used globally. - **Meningococcal B vaccines (MenB)** such as Bexsero and Trumenba specifically target serogroup B, which is a leading cause of meningococcal disease in developed countries. - Combined, these vaccines provide comprehensive coverage against the most epidemiologically important meningococcal serogroups worldwide. *Type A* - While vaccines against **meningococcus type A** do exist (as part of conjugate vaccines), this option is incomplete as it excludes the other important serogroups (B, C, W, Y) for which vaccines are also available. *Type B* - **Type B vaccines** are available and important, particularly in developed countries where serogroup B causes significant disease burden. - However, this option alone is insufficient because vaccines also effectively target other serogroups (A, C, W, Y). *Type A, B, and C* - This option is incomplete because it omits **serogroups W and Y**, for which conjugate vaccines (MenACWY) are readily available and widely used. - The question asks which types vaccines are *available* against, not which are most common, making this an incorrect answer.

Q: Infective form of Hookworms?

Filariform larva. ***Filariform larva*** - The **filariform larva (L3)** is the infective stage of hookworms, capable of penetrating intact skin. - Upon penetration, these larvae migrate through the bloodstream to the lungs, then up the bronchial tree to be swallowed, eventually maturing in the intestines. *Egg* - Hookworm **eggs** are passed in the feces of infected individuals and are not infective to humans directly. - They require favorable conditions (warm, moist soil) to embryonate and hatch into rhabditiform larvae. *Rhabditiform larva* - The **rhabditiform larva (L1)** is the first larval stage that hatches from the egg in the soil. - It is a non-infective, free-living stage that feeds on bacteria and molts twice to become the infective filariform larva. *Adult worm* - **Adult worms** reside in the small intestine of the host and are not the infective form. - They attach to the intestinal mucosa and feed on blood, causing the characteristic anemia associated with hookworm infection.

Q: Which Schistosoma species is primarily associated with eggs being discharged in urine?

S. haematobium. ***S. haematobium*** - *S. haematobium* specifically targets the **urinary bladder plexus**, leading to the discharge of eggs in the **urine**. - Infection with *S. haematobium* is the primary cause of **urinary schistosomiasis** and is associated with complications like **hematuria** and bladder cancer. *S. japonicum (intestinal)* - *S. japonicum* primarily infects the **mesenteric veins of the small intestine** and discharges its eggs in **feces**, not urine. - This species is known for causing severe **intestinal and hepatic schistosomiasis** due to the large number of eggs produced. *S. mansoni (intestinal)* - *S. mansoni* also primarily infects the **mesenteric veins, mainly of the large intestine**, and its eggs are excreted in **feces**. - It is a common cause of **intestinal schistosomiasis**, leading to symptoms such as abdominal pain, diarrhea, and hepatosplenomegaly. *S. mekongi* - *S. mekongi* is another **intestinal schistosome**, closely related to *S. japonicum*, and its eggs are discharged in **feces**. - This species is found in specific regions of Southeast Asia and causes similar symptoms to other intestinal schistosomes.

Question 1

Pseudomonas is which type of bacteria?

Accepted Answer

Aerobic

Answer

Anaerobic

Answer

Microaerophilic

Answer

Obligate anaerobe

Question 2

Which of the following Chlamydia species is primarily associated with respiratory infections?

Accepted Answer

C pneumoniae

Answer

C psittaci

Answer

C trachomatis

Answer

None of the options

Question 3

Which of the following statements about viruses is false?

Accepted Answer

Viruses are capable of independent motility.

Answer

Viruses contain nucleic acid.

Answer

Viruses lack mitochondria.

Answer

Viruses lack ribosomes.

Question 4

Who discovered the bacterium Treponema pallidum?

Accepted Answer

Fritz Schaudinn and Erich Hoffmann

Answer

Robert Koch

Answer

Twort

Answer

Ellerman

Question 5

An adolescent male developed vomiting and diarrhea 1 hour after having food from a restaurant. The most likely pathogen is?

Accepted Answer

Staphylococcus aureus

Answer

Clostridium perfringens

Answer

Vibrio parahaemolyticus

Answer

Salmonella

Question 6

Cylindrical helminths are -

Accepted Answer

Roundworms

Answer

Tapeworms

Answer

Flukes

Answer

Hookworms

Question 7

Most common site for hydatid cyst

Accepted Answer

Liver

Answer

Lung

Answer

Brain

Answer

Kidney

Question 8

Vaccines are available against which types of meningococcus?

Accepted Answer

Type A, B, C, W, and Y

Answer

Type A

Answer

Type B

Answer

Type A, B, and C

Question 9

Infective form of Hookworms?

Accepted Answer

Filariform larva

Answer

Egg

Answer

Rhabditiform larva

Answer

Adult worm

Question 10

Which Schistosoma species is primarily associated with eggs being discharged in urine?

Accepted Answer

S. haematobium

Answer

S. japonicum

Answer

S. mansoni

Answer

S. mekongi

NEET-PG 2013 — Microbiology