Author(s): Greenberg RN, Bollinger M, Compton J
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Abstract The effects of amikacin in combination with aztreonam were tested on 100 strains of gram-negative bacteria by means of the microtiter checkerboard system. Eighty-one strains were Pseudomonas aeruginosa, eight were Enterobacter species, seven were Acinetobacter species, two were Alcaligenes species, one was a Citrobacter organism, and one was Pseudomonas stutzeri. All strains had a minimal inhibitory concentration (MIC) to aztreonam between 4 and 256 micrograms/ml (MIC50 = 16 micrograms/ml) and an MIC to amikacin between 8 and greater than 128 micrograms/ml (MIC50 = 16 micrograms/ml). A synergistic effect (fourfold less MIC when both aztreonam and amikacin were present) was observed for 40 (49\%) of 81 P aeruginosa and three (16\%) of 19 of the other strains tested. All the remaining test strains showed an additive response; no antagonism was observed. The MICs to aztreonam and to amikacin for 98\% of strains that exhibited synergism ranged from 2 to 32 micrograms/ml.
This article was published in Clin Ther
and referenced in Clinical & Medical Biochemistry