COMBINED ACTION OF ANTISEPTICS WITH LOCAL ANESTHETICS AGAINST MULTIDRUG-RESISTANT STRAINS OF S. AUREUS

The aim of this study was to determine the combined action of the most widely used antiseptics with LAs against MDR strains of S. aureus. Materials and methods. The study used 54 clinical MDR strains of S. aureus, isolated during 2022-2024 from patients with infected wounds. Isolation from patients, final identification of microorganisms and sensitivity of the obtained isolates to antibiotics were performed by standard culture method using an automatic bacteriological analyzer Vitec 2 compact (Biomerioux, France). MDR strains of S. aureus were tested for their sensitivity to antiseptics: 0.05% chlorhexidine bigluconate (CH), 0.02% decamethoxine (DСM), and local anesthetics: 2.0% lidocaine solution, 3.0% mepivacaine solution, 4.0% articaine solution. The sensitivity of selected bacterial cultures to antiseptics and local anesthetics was determined using the standard serial microdilution method with the determination of the minimum inhibitory concentration (MIC). The result of determination of combined effect of antiseptics and local anesthetics was evaluated using the fractional inhibitory concentration index (FICI). Results. It was established that the MIC of CH for MDR strains of S. aureus exceeded MIC of DCM significantly in 4 times (p0.0001). The most effective was articaine, that significantly exceeded the antimicrobial activity of lidocaine by 1.5 times (p0.005) and almost twice – of mepivacaine (p0.0001). Conclusions. The FIIC of the combined effect of CH with lidocaine and mepivacaine indicated their indifferent combined effect with the antiseptic. A similar trend was observed when determining the sensitivity of S. aureus strains to the combination of DCM with local anesthetics. The combinations of CH and DCM with articaine separately contribute to a decrease in the MIC of antiseptics for the studied bacterial strains, indicating their additive antimicrobial combined effects.