Antimicrobial Drugs MCQs


1. Choose the antimicrobial which acts by interfering with DNA function in the bacteria:

A. Chloramphenicol

B. Ciprofloxacin

C. Streptomycin

D. Vancomycin

ANSWER: [   B   ]


2. Which antibiotic is primarily bacteriostatic but becomes bactericidal at higher concentrations:

A. Erythromycin

B. Tetracycline

C. Chloramphenicol

D. Ampicillin

ANSWER: [   A   ]


3. Select the antibiotic that has a high therapeutic index:

A. Streptomycin

B. Doxycycline

C. Cephalexin

D. Vancomycin

ANSWER: [   C   ]


4. The following organism is notorious for developing antimicrobial resistance rapidly:

A. Streptococcus pyogenes

B. Meningococcus

C. Treponema pallidum

D. Escherichia coli

ANSWER: [   D   ]


5. Widespread and prolonged use of an antibiotic leads to emergence of drug resistant strains because antibiotics:

A. Induce mutation in the bacteria

B. Promote conjugation among bacteria

C. Allow resistant strains to propagate preferentially

D. All of the above

ANSWER: [   C   ]


6. The most important mechanism of concurrent acquisition of multidrug resistance among bacteria is:

A. Mutation

B. Conjugation

C. Transduction

D. Transformation

ANSWER: [   B   ]


7. Drug destroying type of bacterial resistance is important for the following antibiotics except:

A. Cephalosporins

B. Tetracyclines

C. Chloramphenicol

D. Aminoglycosides

ANSWER: [   B   ]


8. Acquisition of inducible energy dependent efflux proteins by bacteria serves to:

A. Secrete exotoxins

B. Enhance virulance

C. Lyse host tissue

D. Confer antibiotic resistance

ANSWER: [   D   ]


9. Methicillin resistant staphylococci do not respond to β -lactam antibiotics because:

A. They produce a β-lactamase which destroys methicillin and related drugs

B. They elaborate an amidase which destroys methicillin and related drugs

C. They have acquired penicillin binding protein which has low affinity for β-lactam antibiotics

D. They are less permeable to β-lactam antibiotics

ANSWER: [   C   ]


10. The following strategy will promote rather than curb emergence of antibiotic resistant micro-organisms:

A. Whenever possible use broad spectrum antibiotics

B. Prefer a narrow spectrum antibiotic to a broad spectrum one if both are equally effective

C. Prefer short and intensive courses of antibiotics

D. Use antibiotic combinations for prolonged therapy

ANSWER: [   A   ]


11.  Superinfections are more common with:

A. Use of narrow spectrum antibiotics

B. Short courses of antibiotics

C. Use of antibiotics that are completely absorbed from the small intestines

D. Use of antibiotic combinations covering both gram positive and gram negative bacteria

ANSWER: [   D   ]