Send to:

Choose Destination
See comment in PubMed Commons below
Antimicrob Agents Chemother. 1977 Sep;12(3):368-72.

Function of the outer membrane of Escherichia coli as a permeability barrier to beta-lactam antibiotics.


On the basis of a simple theoretical model, the ease of penetration of beta-lactam antibiotics through the outer membrane of Escherichia coli was measured. The cell envelope was found to act as a diffusion barrier to both penicillins and cephalosporins. The validity of the model and the cooperative action of cell-bound beta-lactamase and outer membrane were further verified by comparing calculated and experimentally determined velocities of beta-lactam hydrolysis by intact cells and sonically treated cell suspensions. The results showed good correspondence at five different antibiotic concentrations. Similar conclusions could be drawn from a comparison of beta-lactam concentrations on both sides of the outer membrane, calculated from enzyme kinetic measurements and minimal inhibitory concentrations for both a beta-lactamase-producing E. coli and its enzyme-negative variant. in the case of benzylpenicillin and cephalothin, however, no correspondence was found. The joint action of several parameters determining the efficacy of penicillins and cephalosporins against beta-lactamase-producing E. coli is discussed.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk