INI-CET 2018 - Microbiology PYQs Practice Questions

Q: A patient has the following rash in the groin. Which of the following cannot be a cause?

Aspergillus. ***Aspergillus*** - **Aspergillus** is a **mold (filamentous fungus)**, NOT a dermatophyte, and therefore **cannot cause tinea cruris** (jock itch). - Dermatophytes (Trichophyton, Microsporum, Epidermophyton) are specialized fungi that digest keratin and cause superficial skin infections with characteristic ringworm patterns. - Aspergillus typically causes invasive infections in immunocompromised patients (invasive aspergillosis), allergic bronchopulmonary aspergillosis (ABPA), or rarely deep cutaneous infections in severely immunocompromised individuals—not superficial groin rashes. - **Key distinction:** Tinea cruris = dermatophyte infection; Aspergillus = opportunistic mold *Microsporum* - **Microsporum** species are dermatophytes that CAN cause tinea cruris, though less commonly than Trichophyton and Epidermophyton. - *M. canis* is the most common species, typically causing **tinea capitis** (scalp) and **tinea corporis** (body), but can extend to the groin area. - While not the most frequent cause, it remains a possible etiology and should not be excluded. *Epidermophyton* - **Epidermophyton floccosum** is one of the **most common causes** of tinea cruris. - Presents with itchy, erythematous, scaling patches with well-defined, elevated borders in the inguinal folds. - Thrives in warm, moist environments, making the groin an ideal location. - **Classic presentation:** bilateral involvement with central clearing and advancing scaly borders. *Trichophyton* - **Trichophyton rubrum** is the **MOST common** cause of tinea cruris worldwide, followed by **T. mentagrophytes**. - Causes characteristic pruritic, erythematous, annular or serpiginous lesions with raised, scaly borders. - T. rubrum accounts for the majority of dermatophyte infections in the groin, feet, and nails. [Practice more Microbiology PYQs on OnCourse]

Q: Post kidney transplantation, a patient presents with diarrhoea. The motility of the worms is shown in the figure. Correct statement about the organism is: (AIIMS Nov 2018)

Loeffler pneumonia is caused by the same organism. ***Loeffler pneumonia is caused by the same organism*** - The image shows **Strongyloides stercoralis larvae** with characteristic motility. In a post-kidney transplant patient with diarrhea, this points to **Strongyloides hyperinfection** due to immunosuppression. - **Loeffler's syndrome (Loeffler pneumonia)** is a transient pulmonary infiltrative disease with eosinophilia, caused by larval migration through lungs. It is classically associated with *Strongyloides stercoralis*, *Ascaris lumbricoides*, and hookworms during their migratory phase. - This option represents an important **clinical association** that connects the organism to a significant pulmonary manifestation. *Monoecious organism related with parthenogenesis* - *Strongyloides stercoralis* is **dioecious (unisexual)**, not monoecious, meaning it has separate male and female forms. - While the parasitic females do exhibit **parthenogenesis** (reproducing without fertilization), the organism is not monoecious. *Transmitted by intake of contaminated food and water* - This is **incorrect**. *Strongyloides stercoralis* is transmitted through **percutaneous penetration** by filariform larvae from contaminated soil. - Fecal-oral transmission via contaminated food/water applies to parasites like *Entamoeba histolytica*, *Giardia*, *Ascaris*, and *Enterobius*, but not *Strongyloides*. *Infection occurs by filariform larvae* - This statement is **factually correct** - infection with *Strongyloides* does occur through **filariform (L3) larvae** penetrating intact skin. - However, in the context of this PYQ, Option C is preferred as it highlights the **clinically significant pulmonary manifestation** (Loeffler's syndrome) that is particularly relevant in immunocompromised patients, while this option merely describes the mode of transmission without clinical correlation. [Practice more Microbiology PYQs on OnCourse]

Q: The technique shown in the picture is used for: (AIIMS Nov 2018)

Synthesis of monoclonal antibodies. ***Synthesis of monoclonal antibodies*** - The image depicts the process of creating **hybridomas** by fusing antibody-producing spleen cells from an immunized mouse with myeloma cells. - These hybridomas are then cultured in **HAT medium** to select for stable cell lines that continuously produce a single type of antibody, known as **monoclonal antibodies**. *Preparing cell lines for viral culture* - While cell cultures are used for viral studies, the specific methodology shown involving immunization, spleen cell extraction, and fusion with myeloma cells is not for preparing routine **viral cultures**. - Viral culture typically involves growing target cells that are susceptible to a virus and then inoculating them with the virus for replication and study. *Synthesis of vaccine* - **Vaccine synthesis** involves producing antigens (e.g., inactivated viruses, attenuated microbes, or recombinant proteins) to stimulate an immune response, not the production of antibodies themselves. - The process shown aims to generate antibodies, which could *potentially* be used therapeutically, but not primarily for vaccine production. *Process of genetic engineering* - **Genetic engineering** involves manipulating an organism's genes, such as introducing foreign DNA or modifying existing genes. - While molecular biology techniques are involved in antibody production, the core process of fusing cells to create hybridomas specifically for large-scale antibody production is distinct from typical genetic engineering methods like gene cloning or gene editing. [Practice more Microbiology PYQs on OnCourse]

Q: The life cycle shown below is of:

Nipah virus. ***Nipah virus*** - The diagram clearly illustrates the transmission pathways characteristic of Nipah virus, involving **fruit bats (flying foxes)** as primary reservoirs, **pigs as intermediate hosts**, and human infection through direct contact with infected animals or consumption of **contaminated date palm sap**. - The described "rapid pig-to-pig transmission" and "people consume contaminated date palm sap" are key epidemiological features of Nipah virus outbreaks in Southeast Asia. *Japanese encephalitis* - Japanese encephalitis is primarily transmitted by **mosquitoes** (Culex species) and involves **water birds** as primary reservoirs, and pigs as amplifying hosts. - The life cycle shown does not depict mosquito vectors or water birds, which are central to Japanese encephalitis transmission. *Chandipura virus* - Chandipura virus is an arbovirus transmitted by **sandflies** and often associated with seasonal outbreaks of acute encephalitis, primarily affecting children. - Its transmission cycle does not involve bats, pigs, or contaminated date palm sap as depicted in the image. *Influenza* - Influenza viruses circulate mainly among **humans, birds, and pigs**, with transmission primarily through **respiratory droplets** or direct contact. - While pigs can play a role in certain influenza strains (e.g., swine flu), the involvement of bats and consumption of contaminated sap is not characteristic of human influenza transmission. [Practice more Microbiology PYQs on OnCourse]

Question 1

A patient has the following rash in the groin. Which of the following cannot be a cause?

Accepted Answer

Aspergillus

Answer

Microsporum

Answer

Epidermophyton

Answer

Trichophyton

Question 2

Post kidney transplantation, a patient presents with diarrhoea. The motility of the worms is shown in the figure. Correct statement about the organism is: (AIIMS Nov 2018)

Accepted Answer

Loeffler pneumonia is caused by the same organism

Answer

Monoecious organism related with parthenogenesis

Answer

Transmitted by intake of contaminated food and water

Answer

Infection occurs by filariform larvae

Question 3

The technique shown in the picture is used for: (AIIMS Nov 2018)

Accepted Answer

Synthesis of monoclonal antibodies

Answer

Preparing cell lines for viral culture

Answer

Synthesis of vaccine

Answer

Process of genetic engineering

Question 4

The life cycle shown below is of:

Accepted Answer

Nipah virus

Answer

Japanese encephalitis

Answer

Chandipura virus

Answer

Influenza

INI-CET 2018 — Microbiology