TABLE 1.

Modes of action and resistance mechanisms of commonly used antibioticsa

Antibiotic classExample(s)TargetMode(s) of resistance
β-LactamsPenicillins (ampicillin), cephalosporins (cephamycin), penems (meropenem), monobactams (aztreonam)Peptidoglycan biosynthesisHydrolysis, efflux, altered target
AminoglycosidesGentamicin, streptomycin, spectinomycinTranslationPhosphorylation, acetylation, nucleotidylation, efflux, altered target
GlycopeptidesVancomycin, teicoplaninPeptidoglycan biosynthesisReprogramming peptidoglycan biosynthesis
TetracyclinesMinocycline, tigecyclineTranslationMonooxygenation, efflux, altered target
MacrolidesErythromycin, azithromicinTranslationHydrolysis, glycosylation, phosphorylation, efflux, altered target
LincosamidesClindamycinTranslationNucleotidylation, efflux, altered target
StreptograminsSynercidTranslationC-O lyase (type B streptogramins), acetylation (type A streptogramins), efflux, altered target
OxazolidinonesLinezolidTranslationEfflux, altered target
PhenicolsChloramphenicolTranslationAcetylation, efflux, altered target
QuinolonesCiprofloxacinDNA replicationAcetylation, efflux, altered target
PyrimidinesTrimethoprimC1 metabolismEfflux, altered target
SulfonamidesSulfamethoxazoleC1 metabolismEfflux, altered target
RifamycinsRifampinTranscriptionADP-ribosylation, efflux, altered target
LipopeptidesDaptomycinCell membraneAltered target
Cationic peptidesColistinCell membraneAltered target, efflux
  • a Adapted from reference 150a with permission of the publisher.