The Action of Tetracycline and Chloramphenicol Alone and in Admixture on the Growth of Escherichia Coli

Abstract

The dependence of E. coli growth rates upon chloramphenicol concentration has been established. Chloramphenicol and tetracycline are equivalent in their action on E. coli and their combined effects on growth rate are additive. The decrease in rate of growth is a function of the first power of concentration of either antibiotic or combinations of them. A new mechanism of action is implied when the growth rate decreases to negative values: at this stage the rate of decrease is a function of a fractional power of the concentration.