Do beta-lactam antibiotics permeabilize the outer membrane of gram-negative bacteria? An electrochemical investigation.
The effects of cefotaxime and EDTA on the reducing activity of Escherichia coli and Staphylococcus aureus cultures growing in the presence of lipoic acid (LA) were investigated by potential-time measurements. The potentiometric responses of E. coli cultures exposed to EDTA indicated enhanced transmembrane transport of LA as a consequence of the outer membrane permeabilization by the chelator, whereas EDTA exerted no effect on the reducing activity of S. aureus cultures. In the same way, cefotaxime stimulated the reducing activity of E. coli, but not that of S. aureus. These results suggest that cefotaxime, and, more generally, a great variety of beta-lactam antibiotics, are able to permeabilize the outer membrane of Gram-negative bacteria.
Jouenne
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Laboratoire des Polymères, Biopolymères, Membranes, Unité de Recherche Associée au CNRS No. 500, Faculté des Sciences de Rouen, Mont-Saint-Aignan, France.
Junter
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GA
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D002439:Cefotaxime / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects*; D004492:Edetic Acid / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D008564:Membrane Potentials; D013211:Staphylococcus aureus / Q000378:metabolism*; D008063:Thioctic Acid / Q000378:metabolism
D000900:Anti-Bacterial Agents; D008063:Thioctic Acid; D004492:Edetic Acid; D005947:Glucose; D002439:Cefotaxime