Characteristics and Expression of Tetracycline Resistance in Gram-Negative Bacteria Carrying the Pseudomonas R Factor RP1

Abstract
The Pseudomonas R factor RP1 determines an inducible tetracycline resistance similar to that described for Escherichia coli R factors. The level of RP1-determined resistance measured by minimal inhibitory concentration testing is dependent on the host bacteria and corresponds to the magnitude of decrease in tetracycline accumulation by RP1-containing organisms. The tetracycline resistance mechanism is inactivated at low temperatures. The effect of metabolic inhibitors on tetracycline accumulation by susceptible organisms under various conditions indicates a possible nonspecific effect of cellular energy metabolism on tetracycline uptake.