Effect of 3,3ʹ-diindolylmethane in different solvents on Pseudomonas aeruginosa biofilm

Abstract

Today, the most common pathogens causing nosocomial infections are Gram-negative bacteria, especially Pseudomonas aeruginosa. One of the leading factors in determining the resistance of bacteria is their ability to form biofi lms.One promising class of agents capable of aff ecting biofi lms is indoles (diindolylmethane). Th e aim of this work was to determine the eff ect of diindolylmethane in diff erent solvents on the formation of P. aeruginosa biofi lm. Methods. For microbiologic examination, biological material was collected from purulent-infl ammatory complicated gunshot and shrapnel wounds. Th e antimicrobial activity of samples containing 0.5% solution of 3,3’-diindolylmethane derivatives (Ts-D5-1 – sample 1, Ts-D8-1 – 2, VE-D67-1 –3, VE-D68-1–4, VE-D71-1–5, W-014-1–6, W-015-1–7, and W-016-1–8 in dimethylsulfoxide solvent and Ts-D5-2 – 9, Ts-D8-2 – 10, VE-D67-2 – 11, VE-D68-2 –12, VE-D71- 2 – 13, W-014-2 – 14, W-015-2 – 15,and W-016-2 – 16 in N-methylpyrrolidone solvent) was determined. Th e study was carried out by the method of diff usion in agar. Th e biofi lm formation study was performed according to the method of O’Toole. Results. Samples 14, 15, and 16 showed a high antimicrobial activity, among which sample 14 was the most effi cient: the diameter of the lysis zone was 10 mm aft er 24 hours, 11 mm aft er 48 hours, and 12 mm aft er 72 hours. It was demonstrated that all other samples had less marked antibacterial activity, which was slightly potentiated over time. Conclusions. Sample 14 showed the highest antimicrobial activity. Moreover, the eff ect of potentiation of the antimicrobial activity of the solution was observed. Th e test solution prevented the formation of a biofi lm when it was applied to the well surface, and also led to the destruction of the already formed daily biofi lm of P. aeruginosa.