Question 22

Outline the mechanism of action of ampicillin, gentamicin, vancomycin and ciprofloxacin. 
How does resistance develop to each of these antibiotics? 

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College Answer

The question could have been answered succinctly using a table. Better answers included detail 
of how antibiotics inhibited enzymes, effects on ribosomal subunits, and impact on cell wall 
synthesis or inhibit DNA gyrase. The mechanism of resistance required an understanding of 
beta-lactam inhibition, gene mutation altering target enzymes and ribosomal subunits, and efflux 
mechanisms. Mention of Van A and Van B phenotypes was also sought.