Abstract

A total of 300 isolates of Aeromonas Hydrophila isolated from water and stool samples were tested using the Vitek 2 system, disk diffusion, MicroScan Walkaway and E-test for antimicrobial susceptibility testing. For the total of 34 antimicrobial tested, the MICs agreement was 99.7% for isolates from all sources. Almost 100% of isolates were resistant to ampicillin using both methods with the MIC ranging from 1 to 64 µg/ml. Overall; the agreement of the AST results among all four methods for the drugs tested was (100%) Aminoglycosides, (100%) Carbapenems, (100%) Monobactams, 93% Cephalosporins and 89.4% Beta-lactam/ Beta-lactam inhibitors. Overall agreement between the disk diffusion, MicroScan Walkaway and Vitek methods was 98%, respectively. In general, discrepancies among the methods were due to isolates being interpreted as intermediately susceptible or due to an increased number of resistances detected with disk diffusion and a lower number with Vitek and MicroScan Walkaway.

Key words: Vitek 2 system, E-Test, MICs, micro scan walkway, diarrhea.