Activation of formation of bacterial biofilms by azithromycin and prevention of this effect

Abstract

Growth of members of most of the studied genera of gram positive (Dietzia, Kocuria, and Rhodo coccus) and gram negative bacteria (Pseudomonas and Chromobacterium) in biofilms exhibited higher resis tance to a translation inhibitor, azithromycin compared to the growth of planktonic cultures of the same strains. Low concentrations of azithromycin were found to stimulate biofilm formation by the studied saprotrophic strains. The rate of synthesis of the polysaccharide matrix component exceeded the rate of cell growth, indicating implementation of the biofilm phenotype under these conditions. It was found that an alkylhydroxybenzene (AHB) compound 4 hexylresorcinol was capable of almost uniform suppression of growth of both planktonic cultures and biofilms of the saprotrophic strains under study. In some cases, com bined action of azithromycin and AHB resulted in an additive inhibitory effect and prevented the stimulation of biofilm growth by subinhibitory azithromycin concentrations. Thus, AHB may be considered a promising antibiofilm agent.

Composition and functions of the extracellular polymer matrix of bacterial biofilms

“…In Burkholderia biofilms, the EPM polysaccharides were shown to play an impor tant role in these processes [50]. For some bacteria, impaired synthesis of acidic polysaccharides was shown to increase the sensitivity of their biofilms to such impacts [51][52][53].…”

“…Mutation of the cviI gene encoding AHL synthase in Chromobacterium violaceum was recently shown to result in impaired synthesis of the polysac charide components of the biofilm EPM, which is accompanied by an increase of the biofilm sensitivity to extreme environmental impacts and to antibiotics [51,53].…”

Regulation of biofilm formation by Pseudomonas chlororaphis in an in vitro system

“…The biofilms were obtained and their sensitivity to inhibitors was studied as described previously [9].…”

“…This value was plotted on the graphs (Figs. [2][3][4][5][6][7][8][9]. The relative growth of biofilms was calculated similarly (based on optical density of the dyes extracted from preliminary stained biofilms).…”

“…It was shown recently that inactivation of the AHL synthase gene cviI in Chromobacterium violaceum leads to impaired synthesis of the components of the polysaccharide extracellular polymer matrix (EPM), accompanied by increased sensitivity of the biofilms to extreme envi ronmental conditions and antibiotics [8,9].…”