Postantibiotic suppression of bacterial growth

Rev Infect Dis. Jan-Feb 1981;3(1):28-37. doi: 10.1093/clinids/3.1.28.


Persistent suppression of bacterial growth following exposure of both gram-positive and gram-negative bacteria to numerous antimicrobial agents was studied. The persistent, or postantibiotic, effect was quantitated by periodic counts of colony-forming units after removal of the drug by washing, dilution, or inactivation with penicillinase. Although a postantibiotic effect was observed with all drugs studied, there were marked differences among drugs in their postantibiotic effects on certain organisms. With gram-positive organisms, concentrations of beta-lactam antibiotics near the minimal inhibitory concentration produced persistent effects lasting 1-3 hr. With gram-negative organisms much higher concentrations were required to elicit a postantibiotic effect. Inhibitors of protein and RNA synthesis produced the longest persistent suppression of growth, which was of comparable duration in gram-positive and gram-negative bacteria. Only a short persistent effect of gentamicin was observed with Staphylococcus aureus and Escherichia coli, but a postantibiotic effect lasting 1.6-2.6 hr was observed with Pseudomonas aeruginosa. The duration of the postantibiotic effect was related linearly to concentration of drug and duration of exposure up to a point of maximal response. Persistent effects following exposure to antibiotics were also demonstrated in 90% human serum.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / blood
  • Anti-Bacterial Agents / pharmacology*
  • Bacteria / drug effects*
  • Bacteria / growth & development
  • Biological Availability
  • Dose-Response Relationship, Drug
  • Erythromycin / administration & dosage
  • Erythromycin / blood
  • Erythromycin / pharmacology
  • Escherichia coli / drug effects
  • Gentamicins / administration & dosage
  • Gentamicins / pharmacology
  • Klebsiella pneumoniae / drug effects
  • Microbial Sensitivity Tests
  • Penicillins / administration & dosage
  • Penicillins / blood
  • Penicillins / pharmacology
  • Proteus mirabilis / drug effects
  • Pseudomonas aeruginosa / drug effects
  • Staphylococcus aureus / drug effects
  • Streptococcus pneumoniae / drug effects
  • Time Factors


  • Anti-Bacterial Agents
  • Gentamicins
  • Penicillins
  • Erythromycin