Biology

Antibiotics and Immunity

974 Questions

Prepare for your science sections with these questions on antibiotics and immunity. The hub covers various classes of antibiotics, their sources, and mechanisms of microbial resistance. It also addresses the human antiviral response.

Antibiotic classes and sourcesMicrobial resistance mechanismsAntiviral proteinsDisease treatments

Antibiotics and Immunity Questions

Multiple choice

The drugs penicillin was first purified by:

  1. Dr. Alexander Flemming

  2. Dr. H.W. Florey

  3. Dr. Waksman

  4. Dr. Duggar
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alexander Fleming discovered penicillin in 1928, but the first successful purification and isolation of pure penicillin was achieved by Howard Florey and Ernst Chain in the late 1930s. Fleming's original penicillin was unstable and difficult to purify. Florey and Chain's work made penicillin usable as a drug.

Multiple choice

From which of the following species of Penicillium was the drug penicillin obtained by Flemming?

  1. P. notatum

  2. P. roguefoth

  3. P. camemberti

  4. P. chrysogenum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Alexander Fleming discovered penicillin in 1928 from the mold Penicillium notatum. This species produced the antibiotic compound that inhibited bacterial growth. While industrial production later used P. chrysogenum for higher yields, the original discovery was from P. notatum. P. camemberti is used in cheese production, and P. 'roguefoth' appears to be a misspelling or non-existent species name.

Multiple choice

Which of the following statements is/are false?

a. All viruses live inside host cells, whereas bacteria very rarely do. b. Virus, bacteria, fungi and worms multiply very quickly. c. Most broad spectrum antibiotics work against many species of bacteria.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct option as this statement is false. Virus, bacteria and fungi multiply very quickly, but worms multiply very slowly.

Multiple choice

HACEK group includes all, except

  1. hemophilus aprophillus

  2. acinetobacter baumanni

  3. eikenella corrodens

  4. cardiobacterium hominis
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The HACEK group of fastidious gram-negative bacteria includes Haemophilus aphrophilus (now Aggregatibacter aphrophilus), Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae. Acinetobacter baumannii is not part of HACEK - it's a non-fermenting gram-negative bacillus with different characteristics.

Multiple choice

Which of the following is the medium used for Vibrio cholera?

  1. Thayer-martin

  2. TCBS medium

  3. Skirrow's medium

  4. Loeffer's
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

TCBS agar is the selective medium for Vibrio cholerae, containing sucrose which vibrios ferment (yellow colonies). Thayer-Martin is for Neisseria, Skirrow's for Campylobacter, and Löffler's is for Corynebacterium diphtheriae.

Multiple choice

A child is present with ear infection, with foul smelling discharge. On further exploration, a small perforation is found in the pars flacida of the tympanic membrane. Most appropriate next step in the management would be

  1. topical antibiotics and decongestants for 4 weeks

  2. IV antibiotics and follow up after a month

  3. tympanoplasty

  4. tympano-mastoid exploration
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Foul-smelling ear discharge with perforation in pars flaccida (not pars tensa) strongly suggests cholesteatoma. Pars flaccida perforations are characteristic of acquired cholesteatoma, which requires tympano-mastoid exploration for complete removal and prevention of complications like mastoid infection, intracranial spread, or hearing loss. Topical antibiotics or IV antibiotics alone would be inadequate. Tympanoplasty without mastoid exploration would miss the disease extension.

Multiple choice

A seven and a half years old child presents with non productive cough and mild stridor for 6 months. On oral antibiotics, patient is improving but suddenly develops wheezing, productive cough and mild fever. X-ray shows hyperlucency and PFT shows obstructive curve. Most probable diagnosis is

  1. post viral syndrome

  2. bronchiolitis obliterans

  3. follicular bronchitis

  4. pulmonary alveolar microlithiasis

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Bronchiolitis obliterans causes permanent obstruction following an insult (often viral infection). The progression from mild stridor to obstructive PFT with hyperlucency on imaging, along with initial improvement on antibiotics then worsening with wheezing, fits BO perfectly. Post-viral syndrome is too vague, and other options don't match.

Multiple choice

Consider the following drugs

  1. Greseofulvin
  2. Streptomycin
  3. Quinine Among these, antibiotics would include

  1. 1 and 2

  2. 1 and 3

  3. 2 and 3

  4. 1, 2 and 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Streptomycin is an aminoglycoside antibiotic used to treat bacterial infections like tuberculosis. Griseofulvin is an antifungal antibiotic used to treat fungal infections of the skin, hair, and nails. Quinine is an antimalarial drug, not an antibiotic - it treats protozoan infections (malaria), not bacterial ones. Therefore, only options 1 and 2 are antibiotics.