Abstract
Abstract Aeromonas species are environmental organisms that are responsible for numerous infections in humans and animals. Their antimicrobial susceptibility is usually evaluated using Enterobacteriaceae breakpoints. Although disk diffusion and minimum inhibitory concentration (MIC)- based methods are important for infectious disease management and epidemiological surveys of resistance, comparisons between these two methods have not been extensively studied for Aeromonas isolates. We propose the first extensive comparison of agar dilution and disk diffusion susceptibility testing methods, performed for 20 antimicrobial agents, including unevaluated or incompletely evaluated antibiotics (ticarcillin with or without clavulanic acid, ertapenem, tigecycline), on 146 Aeromonas isolates affiliated with six Aeromonas species via molecular means. We evaluated the level of agreement between Enterobacteriaceae breakpoints-based methods. Reliable agreement (>95%) was observed for piperacillin, cefotaxime, cefepime, nalidixic acid, ofloxacin, ciprofloxacin, gentamicin, amikacin, tetracycline and cotrimoxazole, whereas marked inconsistencies between the methods were noted for carbapenems, amoxicillin-clavulanic acid, ticarcillin, ticarcillin-clavulanic