Detection by the DIRAMIC system of strains of Escherichia coli and Klebsiella spp producing broad-spectrum Betalactamase

Abstract

 Beta-lactam antimicrobials are commonly used in the treatment of infections caused by gram-negative bacteria. However, the increase in antimicrobial resistance has limited its use in patients with these treatments. The purpose of this work was to evaluate the capacity of the DIRAMIC system in the detection of strains producing extended-spectrum betalactamase and its comparison with the double-diffusion confirmatory phenotypic method with discs (DDD). 97 strains previously characterized and identified as Escherichia coli and Klebsiella spp were analyzed, and the sensitivity, specificity and concordance between the results were determined. By using the DDD method, 41 (42.3%) ESBL-producing isolates were detected, and 42 (43.3%) by DIRAMIC-10 system, obtaining a sensitivity of 92.7% and a specificity for the DIRAMIC system 92.9% compared to the double diffusion method with discs. The concordance values ​​found were adequate with a kappa index 0.852, demonstrating the ability of the system to detect betalactamases. The results obtained in the study guarantee the usefulness of the DIRAMIC system as a fast route, to alert the doctor about the presence of ESBL-producing strains, in the best adaptation of antimicrobial treatments and in the improvement of the quality and management of results.