A large outbreak of multiresistant Pseudomonas aeruginosa strains in north-eastern Germany.

Multiply-resistant Pseudomonas aeruginosa were first detected in north-eastern Germany at the end of 1996; since then they have been isolated predominantly from patients in intensive care units. Colonization/infection, especially of the respiratory tract, has been demonstrated in 80 patients, with strains resistant to beta-lactams, carbapenems, aminoglycosides and quinolones. Amikacin showed in-vitro synergy with cefepime, ceftazidime or piperacillin/tazobactam. Horizontal transfer of strains was followed by PFGE and identical strains were detected in the environment, but the source of infection was not established. Rigorous infection control and restricted clinical use of carbapenems limited further dissemination of this outbreak.