CLSI – EUCAST: Comparison of antibiotic-susceptibility profile of Enterobacteriaceae of animal origin according to the standards

Antimicrobial resistance is a relevant “One Health” issue that shows the need of comparison of isolates of different origins. In this way, guidelines for antimicrobial-resistance evaluation in animals are relevant in relation to human sources. This work aims to compare antimicrobial-resistance results of animal isolates considering CLSI and EUCAST guidelines. The comparison shows considerable differences in the results, which include antibiotics used as primary options in hospital infections. EUCAST showed the higher number of samples with resistance profiles than CLSI that indicates a more efficient scenario to the EUCAST to screen antibiotic-resistant bacteria. EUCAST was more consonant to the expected phenotype for ESBL producers, with higher index of resistance to oxyimino-beta-lactam antibiotics. The study shows that there are differences in the interpretative results using different guidelines, where the susceptibility test results concerning Enterobacteriaceae of animal origin are not always coincident in CLSI and EUCAST. EUCAST has proved to be the most reliable alternative for profile screening of antibiotic resistance, when compared to CLSI. We might say the same with respect to the ESBL-producing Enterobacteriaceae, in which EUCAST has proved to be more efficient about the demonstration of expected resistance profiles for the ESBL producers. These differences show that guideline selection might influence the therapeutic option