DIVISION-INHIBITION CAPACITY OF PENICILLIN IN ESCHERICHIA-COLI IS GROWTH-RATE DEPENDENT

Growing bacteria are sensitive to various beta-lactam derivatives due to their interference with peptidoglycan biosynthesis. At low concentr ations, penicillin G (benzylpenicillin) blocks cell division without a ffecting mass growth rate. The MIC for division of Escherichia coli B/ r (H266) was found to depend on the growth rate, which was modified by the nutritional conditions. Our hypothesis, that division sensitivity is proportional to the rate of peptidoglycan synthesis for septum for mation, as well as to cell circumference, was thus confirmed.