Combating Drug Resistance: Mechanisms and strategies in antibiotics & anticancer MCQs With Answer

Combating Drug Resistance: Mechanisms and strategies in antibiotics & anticancer MCQs With Answer

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Introduction: Combating Drug Resistance: Mechanisms and Strategies in Antibiotics & Anticancer MCQs With Answer is a focused study tool for M.Pharm students covering the molecular bases of resistance and contemporary strategies to overcome it. This set emphasizes mechanistic understanding—efflux systems, enzymatic inactivation, target modification, biofilms, persisters, tumor heterogeneity, and microenvironmental influences—and links them to practical interventions such as inhibitors, combination regimens, nanoparticle delivery, synthetic lethality, and biomarker-driven therapy. Each multiple-choice question is designed to test application-level knowledge required in advanced medicinal chemistry, promoting critical thinking for designing or selecting therapeutic strategies against resistant microbes and tumors.

Q1. Which bacterial mechanism primarily reduces accumulation of antibiotics in Gram-negative bacteria by altering outer membrane channels?

  • Upregulation of efflux pumps
  • Production of extended-spectrum beta-lactamases
  • Decreased permeability due to porin loss or modification
  • Methylation of 23S rRNA

Correct Answer: Decreased permeability due to porin loss or modification

Q2. Which compound is a classic beta-lactamase inhibitor used clinically to restore activity of some beta-lactam antibiotics?

  • Vancomycin
  • Clavulanic acid
  • Gentamicin
  • Ciprofloxacin

Correct Answer: Clavulanic acid

Q3. The erm genes confer resistance to macrolides primarily by which mechanism?

  • Active efflux of the drug
  • Methylation of the 23S rRNA binding site
  • Enzymatic hydrolysis of the macrolide lactone
  • Reduced permeability of the cell envelope

Correct Answer: Methylation of the 23S rRNA binding site

Q4. Which efflux pump family is most commonly implicated in multidrug resistance in Gram-negative pathogens?

  • P-glycoprotein (ABCB1)
  • ATP-binding cassette (ABC) full transporters
  • Resistance-Nodulation-Division (RND) family
  • MATE (multidrug and toxic compound extrusion) family

Correct Answer: Resistance-Nodulation-Division (RND) family

Q5. What mobile genetic element is specialized to capture and express gene cassettes, often carrying antibiotic resistance determinants?

  • Plasmid
  • Transposon
  • Integron
  • Bacteriophage

Correct Answer: Integron

Q6. Biofilm-associated resistance to antibiotics is largely due to which combination of factors?

  • Increased mutation rates and plasmid loss
  • Reduced drug penetration and metabolic dormancy of cells
  • Enzymatic degradation by secreted proteases only
  • Exclusive action of efflux pumps

Correct Answer: Reduced drug penetration and metabolic dormancy of cells

Q7. In oncology, overexpression of ABCB1 (P-glycoprotein) in tumor cells causes resistance by what primary mechanism?

  • Increased drug metabolism within lysosomes
  • Enhanced DNA repair
  • Active efflux of chemotherapeutic agents out of the cell
  • Mutation of drug-binding sites on target proteins

Correct Answer: Active efflux of chemotherapeutic agents out of the cell

Q8. The EGFR T790M mutation in lung cancer is an example of which resistance mechanism to tyrosine kinase inhibitors?

  • Drug sequestration in lysosomes
  • Secondary (acquired) mutation in the drug target
  • Increased efflux pump expression
  • Enhanced homologous recombination repair

Correct Answer: Secondary (acquired) mutation in the drug target

Q9. PARP inhibitors exploit synthetic lethality in tumors deficient in which DNA repair pathway?

  • Nucleotide excision repair
  • Base excision repair
  • Non-homologous end joining
  • Homologous recombination repair (e.g., BRCA1/2 deficiency)

Correct Answer: Homologous recombination repair (e.g., BRCA1/2 deficiency)

Q10. Aminoglycoside resistance in many bacteria is frequently mediated by enzymes that modify the drug. Which enzymatic modification is commonly seen?

  • O-demethylation
  • Acetylation, phosphorylation or adenylation of the antibiotic
  • Beta-lactam hydrolysis
  • Methylation of ribosomal proteins

Correct Answer: Acetylation, phosphorylation or adenylation of the antibiotic

Q11. Combining a beta-lactam antibiotic with a beta-lactamase inhibitor is an example of which resistance-combating strategy?

  • Inhibition of target modification enzymes
  • Blocking efflux pump assembly
  • Co-administration of an enzyme inhibitor to protect the antibiotic
  • Enhancing host immune response

Correct Answer: Co-administration of an enzyme inhibitor to protect the antibiotic

Q12. In cancer biology, epithelial-to-mesenchymal transition (EMT) contributes to drug resistance primarily by what process?

  • Increasing cellular proliferation rates only
  • Generating immune-evasive viral mimicry
  • Inducing phenotypic changes that enhance survival, invasion and resistance
  • Upregulating drug-metabolizing enzymes exclusively

Correct Answer: Inducing phenotypic changes that enhance survival, invasion and resistance

Q13. A tumor develops resistance to an EGFR inhibitor by amplifying MET receptor signaling. This exemplifies which resistance mechanism?

  • Pharmacokinetic drug inactivation
  • Bypass or alternative pathway activation
  • Increased drug efflux across the plasma membrane
  • Loss of antigen presentation to immune cells

Correct Answer: Bypass or alternative pathway activation

Q14. Which delivery strategy can help overcome both microbial and tumor cell drug resistance by improving intracellular delivery and avoiding efflux?

  • High-dose bolus administration without formulation changes
  • Nanoparticle- or liposome-based drug delivery systems
  • Oral immediate-release tablets
  • Topical ointment application irrespective of target site

Correct Answer: Nanoparticle- or liposome-based drug delivery systems

Q15. CRISPR-Cas systems engineered as antimicrobials primarily act by which mechanism to combat antibiotic resistance?

  • Inducing broad-spectrum membrane disruption
  • Sequence-specific cleavage of resistance genes in the pathogen
  • Blocking quorum sensing chemically
  • General inhibition of protein synthesis like aminoglycosides

Correct Answer: Sequence-specific cleavage of resistance genes in the pathogen

Q16. Resistance in cancer due to overexpression of anti-apoptotic Bcl-2 family proteins can be targeted by which drug class?

  • Topoisomerase inhibitors
  • BH3-mimetics (Bcl-2 inhibitors)
  • Alkylating agents
  • Methyltransferase inhibitors

Correct Answer: BH3-mimetics (Bcl-2 inhibitors)

Q17. Which adjunctive approach can restore the activity of antibiotics that are substrates for bacterial efflux pumps?

  • Using only bacteriostatic drugs
  • Co-administering efflux pump inhibitors (EPIs)
  • Relying solely on higher dosing of the same antibiotic
  • Promoting bacterial conjugation

Correct Answer: Co-administering efflux pump inhibitors (EPIs)

Q18. Persister cells are a reservoir for recalcitrant infections because they are characterized by which property?

  • Heritable genetic mutations conferring high-level resistance
  • Reversible dormant state with tolerance to antibiotics without genetic change
  • Permanent loss of antibiotic targets
  • Exclusive expression of beta-lactamases

Correct Answer: Reversible dormant state with tolerance to antibiotics without genetic change

Q19. Why is combination therapy effective at limiting selection for resistant microbial or tumor populations?

  • Because combinations always produce toxicity that kills all cells
  • It reduces the probability that a single cell will have simultaneous resistance to multiple agents with different mechanisms
  • It increases mutation rates to expose vulnerabilities
  • It causes permanent inactivation of host immune cells

Correct Answer: It reduces the probability that a single cell will have simultaneous resistance to multiple agents with different mechanisms

Q20. Precision oncology uses biomarkers to guide therapy selection. Which practice best exemplifies this approach?

  • Giving the same chemotherapy regimen to all patients with a tumor type
  • Selecting an EGFR inhibitor only for tumors with validated EGFR-activating mutations
  • Treating tumors based solely on size and stage without molecular tests
  • Using empiric broad-spectrum antibiotics for all cancer patients

Correct Answer: Selecting an EGFR inhibitor only for tumors with validated EGFR-activating mutations

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