Influence of interspecies interactions on biomass and extracellular polymeric substances of bacterial biofilms

BackgroundStudies with emphasis on pure and mixed-species biofilms are of significant importance in understanding biofilm formation mechanisms during microbial infections. This research aims to evaluate pure- dual-species Escherichia coli (code A), Staphylococcus aureus B), Klebsiella pneumoniae C) Pseudomonas aeruginosa D) pathogenic bacterial species their production exopolysaccharides at laboratory scale. MethodsBiofilm biomass (A595) cultures was determined by means a microtiter plate assay triplicate using microplate photometer (Fisher Scientific, type-357). Extracellular polymeric substances (EPS) soluble products (SMP) were extracted from the cells (pure- cultures) alkaline-heat extraction method. Dry weights (g/L) EPS SMP drying samples 105 °C for 8 hours. ResultsKlebsiella accounted 28-72% greater than other bacteria. Experimental values biomasses range 6% 30% over theoretical values. The experimental value one (bacteria B + higher its expected value. Decrease or increase either bacteria A+C B+C combinations totally dependent cell density C. Conclusions Biofilm pure-species species-dependent, four following order: C > D A B. Relation between inconsistent.