Avaliação da multirresistência aos antimicrobianos pelo método disco-difusão e incubação por menadiona em cepas de Escherichia coli de origem nosocomial, selvagem AB1157 e mutante BW535

Abstract

Escherichia coli stands out clinically as an opportunistic bacterium that has emerged as a pathogen causing Healthcare-Associated Infections (HAIs). This bacterium has mechanisms of resistance to antimicrobials. Previous studies have reported the possibility that oxidative stress is aligned with resistance to beta-lactam, aminoglycoside and quinolone antimicrobials. This microorganism has an antioxidant protection system as a defense mechanism against free radicals, whose unpaired electron is centered around oxygen atoms, called ROS (reactive oxygen species), and can originate from exogenous oxidizing agents, such as menadione (MD). This study aims to analyze Escherichia coli strains of clinical origin, the wild-type AB1157 and the mutant BW535, regarding resistance to different classes of antimicrobials and exposure by MD. The different strains of E. coli were subjected to the Antimicrobial Susceptibility Test (AST) and incubated with MD at concentrations of 200 µM to 25 µM, in addition to the control without MD. Thirty-three strains of E. coli of fecal origin (rectal swab) from clinical material were analyzed. In the strains evaluated in the AST, 85.43% of resistance was obtained according to the beta-lactam classes and 51.42% of resistance to aminoglycosides and norfloxacin, which presented 48.57% of resistance in the AST. The multidrug resistance profile of the strains studied in the AST suggests that the changes in the phenotypic profiles of the E. coli strains may occur due to the mechanism of action of the antimicrobials studied in this species. It was found that 48.48% of the strains were resistant, showing a potent reduction in survival due to incubation with MD. Therefore, antimicrobial resistance and the induction of the oxidative agent MD in E. coli highlight the need to control the use of broad-spectrum antimicrobials in order to avoid acquired resistance through the dissemination of resistant genes or oxidative lesions in the bacterial cell, inhibiting the action of these antimicrobials and making treatment in the nosocomial environment difficult