Susceptibility of monospecies and dual-species biofilms of Staphylococcus aureus and Escherichia coli to essential oils

The aim of this study was to investigate the susceptibility of Staphylococcus aureus and Escherichia coli biofilms formed on the polypropylene surface. The cultures were developed for 240 h, planktonic growth was characterized by colony-forming unit (cfu)/mL and biofilms was characterized by quantifying biomass and cfu/cm2. Essential oils (EOs) of citronella and lemon were extracted by hydrodistillation and characterized by gas chromatography. Biofilm formation occured after 3 h of contact. In dual-species biofilms, there was competition; S. aureus was the number of viable cells damaged by E. coli (P < 0.05). The EOs disinfectant action was similar in biofilms monospecies, viable cells and biomass decreased significantly. Dual-species biofilms were more resistant to EOs. The action EOs on biofilm suggest promising alternatives to sanitize industrial polypropylene surfaces.The authors thank the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) for the first author's scholarship, the Fundacao de Amparo a Pesquisa do estado de Minas Gerais (FAPEMIG) for the financial support, the Foundation for Science and Technology and European Community fund European Regional Development Fund (FEDER), in the ambit of the Project PTDC/SAUESA/6460912006/FCOMP-01-0124-FEDER-007480