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. Author manuscript; available in PMC: 2015 Oct 31.
Published in final edited form as: Glob Heart. 2014 Oct 31;9(3):347–358. doi: 10.1016/j.gheart.2014.08.009

Table 1.

Common antibacterial drug targets and selected mechanisms of resistance, by antibiotic class.

Antibiotic class Antibiotic mechanism
of action		 Mechanism(s) of antibiotic resistance
β-lactams
  • -

    penicillins

  • -

    cephalosporins

  • -

    carbapenems

  • -

    monobactams

 Interference with bacterial cell wall synthesis

  1. Production of β-lactamases or extended-spectrum β-lactamases (ESBLs), which hydrolyze and inactivate drug

  2. Change/down-regulation of porins (access points throughbacterial cell membrane,), prohibiting drug entry

  3. Change in configuration of Penicillin binding site (such as encoded by mecA gene in MRSA)
Glycopeptides
  • -

    vancomycin

  • -

    teicoplanin

 Interference with bacterial cell wall synthesis

  1. MRSA: accumulation of cell wall fragments which thicken wall and are capable of binding vancomycin extracellularly; change to several metabolic pathways

  2. Enterococcus and MRSA: acquisition of genes which alters peptide synthesis, reducing glycopeptide affinity
Macrolides, Chloramphenicol, Clindamycin, Quinupristin-dalfopristin, Linezolid Inhibition of protein synthesis- bind to 50S ribosomal subunit

  1. Multi-drug efflux pump systems which pump drug out of cell

  2. Prevention of leader single amino acid substitutions in the chromosomal dihydrofolate reductase peptide synthesis, stopping transcriptional or translational attenuation
Aminoglycosides, Tetracyclines Inhibition of protein synthesis- bind to 30S ribosomal subunit

  1. Expression of aminoglycoside-modifying enzymes

  2. Prevention of leader peptide synthesis, stopping transcriptional or translational attenuation
Fluoroquinolones Interference with bacterial DNA synthesis

  1. Upregulating production of enzymes inactivating the antimicrobial agent

  2. Mutations in DNA gyrase and topoisomerase enzymes involved in RNA production

  3. Drug efflux pump systems which pump drug out of cell
Rifampin Interference with bacterial RNA synthesis Mutation or duplication of drug target, modification cell permeability
Trimethoprim-sulfamethoxazole Inhibition of metabolism (bacterial folate synthesis) Single amino acid substitutions in the chromosomal dihydrofolate reductase (as in S. pneumoniae) leading to decreased binding of drug
Polymixins, Daptomycin Disruption of bacterial membrane structure Mutations altering cell surface charge

Source: Adapted from Tenover FC. Mechanisms of antimicrobial resistance in bacteria. Am J Infect Control 2006,34:S3–10; discussion S64–73, with supplemental information from other sources[20, 102–105].