[Various methods to assay carbenicillin activity against Pseudomonas aeruginosa]

It was shown that the cultures of Pseudomonas aeruginosa were sensitive to 75-100 micrograms/ml and resistant to 25-50 micrograms/ml of carbenicillin when tested by the method of serial dilutions in the synthetic medium developed by the authors and in Jorgensen's medium. The cultures were incubated for 4 and 16 hours, respectively. The data did not confirm the resistance of the cultures to 25-75 and 100 micrograms/ml carbenicillin when it was determined with the serial dilution method in Pal's medium and the disk diffusion method, respectively. The advantages of the medium developed by the authors for testing P. aeruginosa sensitivity to carbenicillin are discussed.