Inhibitory effects of Tamarix hispida extracts on planktonic form and biofilm formation of six pathogenic bacteria

Biofilms are communities of microorganisms embedded in a self-produced extracellular polymeric matrix. Bacterial cells are protected from antimicrobial agents in biofilm structure. Biofilms formation cause many problems in industry, medicine and microbial drug resistance; thus it is essential to find new techniques for removing and inhibiting biofilms. This study aimed to examine the antimicrobial effect of Tamarix hispida alcoholic extracts against six pathogenic bacteria in planktonic and biofim forms. Antimicrobial activities of the plant extracts against the planktonic form of bacteria were evaluated by using the disc diffusion method. MIC and MBC values were determined by a macrobroth dilution technique. Anti-biofilm effects were assessed by microtiter plate method. The results of this study confirmed high ability of T. hispida extracts against the biofilm of tested bacteria and their free-living forms. Methanolic extracts better inhibited bacterial growth and biofilm formation than ethanolic extracts. Anti-biofilm effects of plant extracts were depended on the solvent and extract concentration. The maximum inhibitory effects of T. hispida extracts on biofilm formation, demolish of biofilm structure and inhibition of metabolic activity of bacteria in the biofilm were observed for S. aureus (87/35 %), S. pneumonia (74/49 %) and B. ceruse (88/34 %) respectively. Discussion and In this study the capacity of herbal extracts to encountering whit biofilm was demonstrated and it was confirmed that these extracts have interesting potentiality to become active agents of new drugs.