Practice question

R plasmids, resistance plasmids, carry gene cassettes encoding enzymes that degrade or modify antibiotics, efflux pumps, or target alteration proteins. Common determinants include bla for ampicillin beta-lactamase, tet for tetracycline efflux, cat for chloramphenicol acetyltransferase, and aad for streptomycin adenylyltransferase. They accumulate through transposon insertion and integron capture, producing multidrug-resistant isolates. Spread via conjugation in hospitals accelerates nosocomial infection resistance. Incompatibility grouping classifies R plasmids, and their control relies on understanding replicon dominance and horizontal transfer dynamics in clinical settings.