Mutants of Pseudomonas aeruginosa that show specific hypersensitivity to aminoglycosides.

A class of mutants in Pseudomonas aeruginosa have been found that are tolerant to aeruginocin 41 and also hypersensitive to aminoglycosides. They do not show any changes in susceptibility to a wide range of other toxic agents, including antibiotics and surfactants. This tol locus, tolA, has been mapped at 10 min from the FP2 origin and linked to carA (carbamyl phosphate synthetase) by transduction and conjugation. By selecting for revertants of the hypersensitivity phenotype, revertants to tol(+) were found, indicating that it is the tolA locus that is responsible for this specific hypersensitivity. The results indicate that a specific mechanism exists for the intrinsic resistance of P. aeruginosa to aminoglycosides.