527 AMR Mechanisms

Which of the following best describes the action of β-lactamases in resistant bacteria?

• Blocking ribosomal binding of aminoglycosides

• Hydrolysing the β-lactam ring of antibiotics

• Modifying cell wall porins to reduce permeability

• Methylating the 23S rRNA subunit

Extended-spectrum β-lactamases (ESBLs) primarily confer resistance to which class of antibiotics?

• Macrolides

• Aminoglycosides

• Third-generation cephalosporins

• Glycopeptides

Resistance to macrolides and lincosamides most commonly occurs through:

• Increased efflux of the antibiotic

• Ribosomal methylation of the 23S rRNA subunit

• Synthesis of modified PBPs

• Enzymatic hydrolysis by β-lactamase

Which mechanism is most associated with tetracycline resistance?

• Ribosomal protection or efflux pump synthesis

• Production of altered PBPs

• Methylation of the 16S rRNA subunit

• Inactivation by acetyltransferase enzymes

Quinolone resistance in Gram-negative bacteria primarily results from:

• Alteration of topoisomerase IV

• Mutation in DNA gyrase and reduced porin OmpF expression

• Increased production of β-lactamase

• Methylation of ribosomal RNA

Aminoglycoside resistance commonly involves:

• A. Aminoglycoside acetyltransferases

• B. Efflux of the antibiotic via transporters

• C. Modified lipid membrane structures

• D. Reduced DNA gyrase affinity

Which of the following is an example of a metabolic bypass mechanism?

• Synthesis of a new dipeptide terminus in enterococci

• Synthesis of an alternative dihydropteroate synthetase

• Methylation of rRNA to prevent macrolide binding

• Decrease in outer membrane porin expression

The formation of a D-alanyl-D-lactate terminus confers resistance to:

• Penicillin

• Streptogramin B

• Vancomycin

• Ceftriaxone

Plasmid-mediated integrons primarily contribute to resistance by:

• Hydrolysing β-lactams

• Integrating gene cassettes carrying resistance genes

• Blocking cell wall permeability

• Protecting ribosomal subunits from translation inhibition

According to antimicrobial stewardship principles in the lecture, which is a key programme goal?

• Promote higher antibiotic doses to overcome resistance

• Delay treatment until infection worsens

• Promote optimal selection, dose, frequency, and duration

• Restrict use of all β-lactam antibiotics