The rate of killing of Escherichia coli by beta-lactam antibiotics is strictly proportional to the rate of bacterial growth

J Gen Microbiol. 1986 May;132(5):1297-304. doi: 10.1099/00221287-132-5-1297.


Nongrowing bacteria evade the bactericidal activity of beta-lactam antibiotics. We sought to determine if slow growth rate also alters bactericidal activity. The bactericidal activity of two beta-lactams on Escherichia coli grown in glucose limited chemostats was compared for generation times ranging from 0.7 to 12 h. The degree of killing varied with drug structure and with E. coli strain. However, all killing rates were a constant function of the bacterial generation time: slowly growing bacteria became progressively more phenotypically tolerant to beta-lactam antibiotics as the generation time was extended.

MeSH terms

  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins*
  • Carrier Proteins / analysis
  • Cefamandole / analogs & derivatives
  • Cefamandole / pharmacology
  • Cefonicid
  • Cell Wall / drug effects
  • Escherichia coli / drug effects*
  • Escherichia coli / growth & development
  • Hexosyltransferases*
  • Muramoylpentapeptide Carboxypeptidase / analysis
  • Penicillin G / pharmacology
  • Penicillin Resistance
  • Penicillin-Binding Proteins
  • Peptidyl Transferases*


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Carrier Proteins
  • Penicillin-Binding Proteins
  • CGP 17520
  • Cefamandole
  • Cefonicid
  • Peptidyl Transferases
  • Hexosyltransferases
  • Muramoylpentapeptide Carboxypeptidase
  • Penicillin G