AIIMS Microbiology And Immunology Solved Model Question Paper May 2023

AIIMS Microbiology And Immunology Model Question Paper May 2023

 

Question.1. Assertion: According to central dogma, information flows from DNA to RNA, which is then encoded into protein.

Reason: In retrovirus, reverse of central dogma happens:

1. Both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. Both assertion and reason are true but the reason is not the correct explanation of the assertion
3. Assertion is true but the reason is false
4. Both the assertion and reason are false
5. The assertion is false but reason is true

Answer. (2) (Both assertion and reason are true but the reason is not the correct explanation of the assertion)

Body Fluids	Muscle Physiology	Digestive System
Endocrinology	Face Anatomy	Neck Anatomy
Lower Limb	Upper Limb	Nervous System

Read And Learn More: Micro Biology And Immunology Model Question Papers With Answers

• In central dogma in general, information flows from DNA to RNA—called transcription
• In retroviruses, the reverse happens, information flows from RNA to DNA—called reverse transcription

Question.2. Identify the correct sequence in which the following agents are applied during Gram’s stain procedure.

1. Iodine
2. Acetone
3. Carbol fuchsin
4. Gentian violet

Answer. (4→ 1→ 2→ 3)

Primary stain (gentian or methyl violet) → mordant (iodine) → decolorizer (alcohol) →counter stain (dilute carbol fuchsin or safranin)

Question.3. Which of the following are the cell markers of T Regulatory cell?

1. CD4, CD25
2. FOX2, IL-2
3. CD8 only
4. CD4 only

Answer. (1) (CD4, CD25)

T regulatory cells possess surface markers such as CD4, CD25, and Foxp3 (a forkhead family transcription factor).

Question.4. Which of the following antibodies is involved in allergic hypersensitivity?

1. IgM
2. IgA
3. IgG
4. IgE

Answer. (4) (IgE)

Allergic or type I hypersensitivity is medicated by IgE

Question.5. Mw vaccine is made from which bacteria?

1. M. welchii
2. M. indicus pranii
3. M. avium intracellulare
4. None of the above

Answer. (2) (M. indicus pranii)

MIP vaccine: A killed leprosy vaccine has been recently developed in India in 2018, using Mycobacterium indicus pranii (MIP).

Trials have shown that if the vaccine is given to people in close contact, cases can be brought down by 60% in three years.

Question.6. Clostridium difficile diarrhoea is most commonly associated with:

1. Aminopenicillins
2. Fluoroquinolones
3. Macrolides
4. Carbapenems

Answer. (1) (Aminopenicillins)

Prolonged antimicrobial use is the most important risk factor for Clostridium difficile diarrhea as this can result in disruption of the normal colonic flora, which enhances the susceptibility to C. difficile infection.

• Cephalosporins (e.g. ceftriaxone) are frequently responsible for this condition Other antibiotics, such as clindamycin, ampicillin, and fluoroquinolones (ciprofloxacin) are also implicated in hospital outbreaks
• However, all antibiotics, including vancomycin and metronidazole (which are the drugs of choice in C. difficile infection) have been found to carry a risk of infection, if given for prolonged duration.

Question.7. During the investigation for an outbreak of MRSA in the hospital, it was found that a nurse of NICU had MRSA colonization of anterior nares. What is the best treatment for her?

1. Topical bacitracin
2. Oral vancomycin
3. Inhaled colistin
4. IV cefazolin

Answer. (1) Topical bacitracin

Mupirocin ointment is recommended for Staphylococcus aureus nasal colonization; topical bacitracin can be used alternatively.

Question.8. A patient presented with fever for 8 days and difficulty in breathing for two days, on examination there is red painless rash found on the left side of the chest. What is the most likely diagnosis?

1. Louse-borne typhus
2. Scrub typhus
3. Murine typhus
4. Answer.fever

Answer. (2) (Scrub typhus)

• The classic presentation of scrub typhus consists of triad of an eschar (at the site of bite of chiggers), regional lymphadenopathy and maculopapular rash.
• Non-specific manifestations may appear early, such as fever, headache, myalgia, cough,and gastrointestinal symptoms
• Complications, such as encephalitis and interstitial pneumonia due to vascular injury may occur rarely in the late stage.

Question.9. Chancre redux seen in:

• Donovanosis
• Primary syphilis
• Gonococcal infection
• Chancroid

Answer. (2) (Primary syphilis)

Recurrence of primary chancre in untreated, or is inadequately treated primary syphilis is,within weeks or months later……. is termed chancre redux.

Question.10. Assertion: Large doses of acyclovir are recommended for treating genital herpes in HIV positive patients.

Reason: Frequent recurrence of genital herpes is seen in HIV patients:

1. Both Assertion and Reason are true and Reason is correct explanation of Assertion
2. Assertion is true and reason is not the right explanation for assertion
3. Assertion is false and reason is also false
4. Both assertion and reason are false
5. Both Assertion and Reason are independently a false/incorrect statement

Answer. (1) (Both Assertion and Reason are true and Reason is correct explanation of Assertion)

HSV reactivation is common among persons with HIV-1, long-term suppressive antiviral therapy against HSV should be considered for persons coinfected with HSV-2 and HIV-1. Higher-dose treatments (e.g. acyclovir 800 mg 3 times per day) can be used for those who have frequent HSV outbreaks despite receiving standard suppressive therapy.

Question.11. A 5-year-old child presents with fever and altered sensorium for 3 days. On examination, he has lesions on his palm, sole, and mouth as shown in the image.

What is most likely causative organism?

1. Staphylococcus aureus
2. Measles virus
3. Rubella virus
4. Picorna virus

Answer.(4) (Picorna virus)

• Oral and pharyngeal ulcerations and vesicular rashes of the palms and soles which heal without crusting…. Suggestive of Hand foot mouth disease
• Hand-foot mouth disease is caused by Coxsackievirus A 16; which belongs to Picornaviridae.

Question.12. A lady developed chicken pox during pregnancy. Highest risk of transmission to fetus is at which period of gestation?

1. 11–14 weeks
2. 14–18 weeks
3. 34–37 weeks
4. 28–32 weeks

Answer. (3) (34–37 weeks)

• The risk of transmission of chicken pox is highest during delivery
• The risk of malformation is highest if the mother acquires infection at early pregnancy (25%).

Question.13. Infectious cause of erythema multiforme in given image is:

1. Staphylococcus
2. TB
3. HSV
4. EBV

Answer. (3) (Herpes simplex virus)

Herpes simplex virus accounts for majority of cause erythema multiforme.

Question.14. A young HIV patient with recurrent lessons over genitals as shown in the image. What is the expected microscopic finding in this lesion?

1. Intracytoplasmic inclusion body
2. Intranuclear inclusion body
3. Bacteria with bipolar staining
4. Multinucleated giant cells

Answer. (1) (Intracytoplasmic inclusion body)

• Pearly white like lesion with a dimple at the centre is characteristic feature of molluscum contageosum
• Though children are commonly affected, most commonly spread by direct contact and skin lesions are common; however in HIV-infected patients: disease is more generalized, severe, and persistent, spread by sexual contact, and lesions may be seen on genitals
• Molluscum contagious is characterized by presence of typical intracytoplasmic inclusion bodies in the lesion, called as Henderson Peterson body or Molluscum bodies

15. A patient presented with fever and joint pain for which he was put on NSAIDs. After 10 days the patient developed the following skin lesion. What is the cause for pigmentation?

• Chikungunya
• Dengue
• Fixed drug eruption
• Melasma

Answer. (1) (Chikungunya)

• Patient presented with fever and joint pain; developed skin lesion (pigmentation) over nose….. suggestive of Chikungunya
• Chik sign (also called brownie nose appearance): Rare presentation; characterized by hyper-pigmentation over centrofacial area; occurs due to increased intraepidermal melanin retention triggered by the chikungunya virus. Most patients recover within a week, except for the joint pain (lasts for months).

Question.16. A patient was exposed to hepatitis B infection. Which of the following markers will always be present irrespective of whether the patient recovers from the infection or not?

1. HBsAg
2. Anti Hbs
3. Anti Hbc
4. HBeAg

Answer. (3) (Anti Hbc)

• Anti-Hbc (IgM followed by IgG) will always be present in HBV-infected individuals, even after recovery.
• HBsAg will be present throughout infection but will disappear following recovery. AntiHBs antibodies will not be present during infection; appear only after recovery
  Mycology

Question.17. Which among the following exist in yeast form at 37°C and hyphal form at 25°C?

• Malassezia furfur
• Cryptococcus neoformans
• Aspergillus
• Histoplasma capsulatum

Answer. (4) (Histoplasma capsulatum)

• Yeast form at 37°C and hyphal form at 25°C indicates dimorphic fungi
• Among the options, Histoplasma capsulatum is an example of dimorphic fungi

Question.18. Medlar bodies are found in:

1. Chromoblastomycosis
2. Sporotrichosis
3. Mycetoma
4. Candidiasis

Answer. (1) (Chromoblastomycosis)

1. Medlar bodies are characteristic feature of Chromoblastomycosis
2. Characterized by formation of brown thick walled round cells (5–12 µm size) with multiple internal transverse septa
3. They are also called Medlar bodies or muriform cells or golden-brown septate or copper pennies

Question.19. Components of the Ziehl-Neelson stain used for Cryptosporidium are:

1. Carbolfuschin
2. Methylene blue
3. Iodine
4. Malachite green
5. 1% sulfuric acid

Answer. (a-T, b-T, c-F, d-F, e-T)

• For Cryptosporidium, modified acid-fast staining is used which involves
• Primary staining with Carbolfuschin → decolorization with 1% sulfuric acid → counterstain with Methylene blue

Question.20. Transmission assessment survey is for:

• P. vivax
• P. falciparum
• Leishmania donovani
• Wuchereria bancrofti

Answer. (4) (Wuchereria bancrofti)

Transmission assessment survey is done under filariasis elimination programme.

Question.21. Which of the following diseases is NOT transmitted by it?

1. Kala Azar
2. Chandipur encephalitis
3. Carrion’s disease
4. Babesiosis

Answer. (d) (Babesiosis)

• Sandflies are light or dark brown flies, smaller than mosquitoes, with the following identification features
  • Their body and wings are covered by dense hair
  • Head contains pair of long, slender and hairy antennae, palpi and a proboscis
  • Thorax contains pair of wings and three pairs of legs, abdomen has ten segments
  • Though winged, they only hop about and do not fly
  • The legs are longer as compared to the size of the body

• Sandfly transmits Kala-azar, Oriental sore, Sandfly fever (Papatasi fever) and Oroya fever (Carrion’s disease), Chandipura vesiculovirus/encephalitis virus
• Babesiosis is transmitted by hard ticks

Question.22. Mention the true/false statements about drug resistant malaria:

1. Not present in India
2. Chloroquine with sulfadoxine-pyrimethamine is effective
3. Artemether with lumefantrine is useful
4. Monotherapy with artemisinin derivatives is not useful due to high relapse rate
5. Quinine with clindamycin or doxycycline is still effective treatment

Answer. (a-F, b-F, c-T, d-T, e-T)

• Chloroquine resistance in P. falciparum has been reported since 1973. Highest chloroquine resistance in India has been reported from North East States
• As most drug resistant malaria is chloroquine-resistant, chloroquine with sulfadoxine-pyrimethamine will not be effective
• Artemether with lumefantrine is the recommended regimen for North
• Monotherapy with artemisinin derivatives is not useful due to high relapse rate
• Clindamycin plus quinine is an alternative non-artemisinin-based combination recommended by WHO.

Question.23. Match the following drugs with organism they are used for:

Answer. (1-D, 2-A, 3-B, 4-F)

• Praziquantel is given in cestode and trematodes infections
• Diethylcarbamazine is the DOC of filariasis
• Nitazoxanide: It is indicated for the treatment of infection by
• Cryptosporidium parvum and Giardia lamblia
• Mebendazole: is given in intestinal nematode infections such as ascariasis, hookworm,Trichuris and Enterobius.

Question.24. Mark the following statements regarding malaria as true or false:

1. Black water fever is caused by P. ovale
2. Cerebral malaria is caused by P. falciparum
3. Duffy antigen offers protection against P. vivax
4. Sickle cell anemia aggravates P falciparum malaria
5. Thalassemia aggravates P falciparum malaria

Answer. (1-False, 2-True, 3-False, 4-False, 5-False)

• Black water fever and Cerebral malaria are caused by P. falciparum, not by P. ovale
• P.vivax RBCs negative for duffy antigen offers protection against P. vivax—Duffy blood group antigens present on RBC membrane act as receptors for P. vivax. So, people with Duffy negative RBCs (West Africans) are resistant to vivax malaria
• Patients with Sickle cell disease, hemoglobin C and E, fetal hemoglobin and thalassemia hemoglobin are resistant to falciparum malaria

Question.25. Mark the following statements regarding xenodiagnoses as true or false:

1. Blood from suspected dengue patient can be used for cultivation in Aedes mosquito
2. Effect on rabbit ileal loop is used for diagnosis of ETEC
3. Coxiella is cultivated in eggs synthesize antigen required for antibody detection
4. Sandfly can be grown in Hamster eggs
5. Useful in Chagas’ disease

Answer. (1-True,2-True, 3-True, 4-False, 5-True)

Xenodiagnosis uses laboratory-reared vectors to detect low levels of parasites during chronic stages of the disease, when their numbers in the blood will be very low. This technique is employed to diagnose Chagas’ disease.

Question.26. A patient presented with a rash as given in the image. This condition is associated with which of the following professions?

1. Swimming pool staff
2. Dog kennel cleaner
3. Butcher
4. Poultry worker

Answer. (2) (Dog kennel cleaner)

1. The picture in the given question shows Cutaneous larva migrans (creeping eruption); manifests as rashes in skin and subcutaneous tissue
2. It is mainly caused by filariform larvae of nonhuman hookworm species such as
   Ancylostoma brasiliensis, A.caninum and A. ceylanicum.
3. These hookworm infections are more common in workers exposed to feline animals such as dogs (such as kennel cleaners, workers in pet shops and shelters) where the environment is contaminated due to a large number of dogs and accumulation of feces.
   Hospital Infection Control

Question.27. Match the following:

Answer. (a-5, b-1, c-2, d-4)

• Gloves must be segregated into red bags
• Glassware must be segregated into blue puncture-proof containers
• Scalpel must be segregated into white puncture-proof containers
• Chemical waste must be segregated into yellow bags
• Syringe wrapper as non-infectious, can be segregated into general waste.

Question.28. Which of the following vaccines is/are effective for mass vaccination during a disaster outbreak?

1. Cholera
2. Typhoid
3. Measles
4. Scrub typhus
5. Polio

Answer. (1-False, 2-False, 3-True, 4-False, 5-True)

WHO vaccine recommendations during emergencies:

• The only vaccines consistently recommended in disaster management are- measles and polio
• Vaccines recommended only after the outset of an outbreak: hepatitis A; meningococcal meningitis; and yellow fever
• Vaccines for tetanus, pertussis, and diphtheria are generally not recommended for mass vaccination campaigns and rather should be implemented through routine immunization programs when conditions stabilize.
• Influenza and typhoid vaccines are generally not recommended at all during emergencies, regardless of the phase
• Cholera is not recommended after the start of an outbreak.