THE EFFECT OF SUBINHIBITORY CONCENTRATIONS OF ETHYLMETHYLHYDROXYPYRIDINE SUCCINATE ON BIOFILMS OF MICROORGANISMS

Abstract

Biofilm microorganisms cause about 80% of chronic infections, leading to increased morbidity, increased hospital stays and enhanced health care costs. Biofilms can also grow on abiotic surfaces, including orthopedic prostheses, stents, and catheters. Antibiotics are not effective enough to treat biofilm infections, and antibiofilm agents are being sought among other classes of compounds, in particular antioxidants, including the well-known drug ethylmethylhydroxypyridine succinate (mexidol). The aim of the research was to study the effect of mexidol on the formation of biofilms by test strains of microorganisms. Clinical strains of bacteria (E. coli 311, P. aeruginosa 449, S. aureus 222) and fungi (C. albicans 1486) were used. The antimicrobial activity of mexidol was determined by serial dilutions in liquid media in the concentration range of 1.5-200 μg/ml. Determination of the microorganisms ability to form biofilm was performed according to the known O’Toole method. A degree of the biofilm formation intensity was determined as described by Stepanovic S. et al. The potential antibiofilm activity of mexidol was studied at concentrations of 5–200 μg/ml. Statistical processing of the results was performed using Newman-Keuls criterion by the software StatSoft Statistica 6.0. It was shown that for planktonic forms of E. coli, P. aeruginosa, S. aureus, and C. albicans, the minimum inhibitory concentration of mexidol is more 200 μg/ml. E. coli 311 and P. aeruginosa 449 show a strong ability to form biofilms, S. aureus 222 – the medium ability. C. albicans 1486 does not adhere to the abiotic surface and was no longer used. Mexidol enhances the biofilm production by E. coli 311, increasing the biomass of biofilms by 12–15%. The drug increases the biomass of P. aeruginosa biofilms by 33–110% against control, and this is most pronounced at the minimum concentration of the drug. Mexidol also stimulates the formation of S. aureus 222 biofilms by 2.1-2.7 times compared to the control. Therefore, under the action of the drug at subinhibitory concentrations, stimulation of the biofilm formation by gram-negative (E. coli 311, P. aeruginosa 449) and gram-positive bacteria (S. aureus 222) is observed. The identifiedability of mexidol to stimulate biofilm formation requires further research to assess the feasibility of its use in the complex therapy of purulent-inflammatory diseases.

Keywords

• ethylmethylhydroxypyridine succinate
• mexidol
• microorganisms
• clinical strains
• biofilm.