En Bloc transduction of imipenem resistance with other resistance determinants from a clinical strain of Pseudomonas aeruginosa

In this report we describe a lysogenic strain of Pseudomonas aeruginosa No. 229, from Frankfurt University Clinics, resistant to imipenem (IMI), cefotaxime (CTX), kanamycin (KAN), carbenicillin (CAR) as well as to other non-beta-lactam drugs, from which a wildtype phage could be isolated and used for transduction of an imipenem resistance determinant. All IMI-selected transductants were found to be co-resistant also to CTX, KAN and CAR. Conversely, transductants selected with CTX, KAN or CAR were also all resistant to IMI. It seems probable that IMI is hydrolyzed by the original donor strain as well as by transductant colonies by means of a clavulanate-inhibited beta-lactamase and not by a metallo-beta-lactamase.