Minimal inhibitory concentrations of antimicrobial agents against Aeromonas hydrophila determined with the Autobac MTS.

Minimal inhibitory concentrations of seven antimicrobial agents for 22 strains of Aeromonas hydrophila were determined with the Autobac MTS procedure. The ranges of the minimal inhibitory concentrations were found to be similar to those obtained by a microdilution procedure. Depending upon the interpretive criteria used, there were discrepancies with carbenicillin, cephalothin, kanamycin, and tetracycline. It is recommended that the beta-lactam antibiotics ampicillin, carbenicillin, and cephalothin not be tested because of their lack of clinical usefulness, thus completely eliminating all of the significant discrepancies and reducing expendable costs by 50%.