Galkin M. The peculiarity of Pseudomonas aeruginosa biofilm formation in presence of the porphyrins bismuth complexes

It was shown that porphyrines bismuth complexes can inhibit biomass accumulation, depending of its structure in 2,75-5 times respectively in concentration of 80 µM. Biofilm formation also decreases by 92 %, 72 % and 26 % respectively in presence of Bi(III)-TPP, Bi(III)-TQP and Bi(III)-PP IX. Study of the biofilm formation dynamic, during a week, show that in contrast of a continuously growing biofilm in control, in presence of the Bi(III)-TPP it stops on the 3 day. Inhibition rate depends from the Bi(III)-TPP, and its amount equals 2, 7 and 10 times in concentration 0,4, 40 and 80 µМ on the seventh day. It was shown that autoinducers and major P. aeruginosa exoproducts, controlled by quorum sensing: Las-protease, rhamnolipids and piocyanin biosynthesis significantly inhibited in presence of the discovered substances. It was found that subinhibitory concentrations of the discovered substances can inhibit quorum sensing-depend swarming motility, but do not affect twitching motility, that is due to type IV pili and not depend by quorum sensing. Diameter of the cell distribution in presence of 0,4 µM of the Bi(III)-TPP is 0,5 mm against 25 mm in control. According to data of the exogenic autoinducers action on porphyrines bismuth complexes activity, we proposed hypothetical scheme of a possible intervention of the discovered substances in biofilm formation and quorum sensing functions processes in P. aeruginosa.