Influence of essential oils on the biofilm formation and cell agglomeration of Burkholderia cepacia from industrial environment

Burkholderia cepacia (B. cepacia) is one of nine species the Burkholderia cepacia complex, a group of gram-negative, motile, non-spore-forming and rod-shaped bacteria. Contamination by B. cepacia is found in different industrial issues. B. cepacia affect manufacturing process chains by contaminating the working fluids with planktonic cells and biofilms. Because of the opportunistic pathogenicity to plants, animals, humans and and the multi-drug resistance, B. cepacia is difficult to treat. An alternative treatment method could be the use of herbal raw materials, such as essential oils and their active ingredients. This study aims: (i) to identify the antimicrobial potential of essential oils on the growth of four B. cepacia isolates, (ii) to analyse the influence of active ingredients, on planktonic growth and biofilm formation, (iii) to better understand the impact of commercial and naturally biocides to cell agglomeration as a precursor to mature biofilms. Starting with agar dilution method to evaluate the antimicrobial potential of twenty-three essential oils against B. cepacia (Burk_09, Burk_23, Burk_52 and Burk_309) isolated from cathodic dip coating systems and the wild type (DSM_7288), it was all ready possible to identify eight essential oils that inhibit the growth of B. cepacia. Serial microdilution was used to determine the minimal inhibitory concentration (MIC) of the essential oils for growth and biofilm formation inhibition of B. cepacia. The MIC of Melaleuca alternifolia and Citrus aurantium dulcis essential oils were tested equally for all strains. Essential oils contain active ingredients against the growth of multi-drug resistant and pathogenic bacteria. From twelve active substances among others, Terpinen-4-ol and Geraniol were identified that inhibited growth and biofilm formation. It is concluded that essential oils and active ingredients have a good antimicrobial potential, demonstrating a possible more environmentalfriendly alternative to commercial biocides applying in industrial fluids.