[Susceptibilities of Pseudomonas species to aminoglycosides and tetracyclines].

Pseudomonas aeruginosa has attracted much attention through its role in hospital outbreaks of disease. However, other members of the genus Pseudomonas, particularly Pseudomonas maltophilia and Pseudomonas cepacia, may be isolated as opportunistic pathogens of man, and can be found in hospital materials. These organisms have been less susceptible to the commonly used antibiotics. This report deals with the in vitro sensitivity of Pseudomonas strains except for P. aeruginosa to aminoglycosides and tetracyclines. The following bacteria were tested: P. maltophilia (50 strains), P. fluorescens (29 strains), P. putida (52 strains), P. cepacia (49 strains), P. putrefaciens (18 strains), P. acidovorans (12 strains). All of the strains for this study were isolated from routine cultures of infected clinical materials which sent to the Clinical Laboratories, Juntendo University Hospital during the 1 year period of 1980. The tests for susceptibility of the strains to the 3 aminoglycosides (gentamicin, tobramycin, amikacin) and 3 tetracyclines (tetracycline, doxycycline, minocycline) were all performed by the serial 2-fold agar plate dilution method on heart infusion agar, standardized by the Japan Society of Chemotherapy, using the microplanter apparatus with an inoculum size of approximately 10(8) CFU/ml. There were similar sensitivity patterns for the aminoglycosides tested; most of the strains of P. maltophilia, P. cepacia and P. acidovorans were resistant to the aminoglycosides, while most of P. fluorescens, P. putida and P. putrefaciens were sensitive. Minocycline and doxycycline were extremely active to the Pseudomonas species studied. Tetracycline was almost ineffective against P. maltophilia and P. cepacia.