Ação de óleos essenciais sobre biofilmeformado por Cronobacter sakazakii em superfície de polipropileno

Abstract

Cronobacter sakazakii is a gram-negative pathogenic bacteria, aerobic optional, that belongs to the family Enterobacteriaceae and is associated with significant morbidity and mortality, especially among newborns. It has been an important contaminant in powdered milk and infant formula, presenting ability to form biofilm. When in biofilm C. sakazakii may exhibit major tolerance to sanitizing agents, and thus the development of new sanitizing agents is significant. In this context, the essential oils have gained prominence. So the object of this study was to evaluate the antimicrobial activity of various essential oils on planktonic cells and in biofilm of C. sakazakii in polypropylene surface. It was studied the antimicrobial effect of essential oils of Cinnamomum cassia, Origanum vulgare, Mentha piperita, Litsea cubeba, Foeniculum vulgare, Cinnamomum camphora, Illicium verum, Myristica fragans, Thymus vulgaris, Citrus nobilis, Syzygium aromaticum and Ocimum basilicum on planktonic cells and sessile of Cronobacter sakazakii. It were evaluated 10 tests on the synergism of cinnamon, mint and ho wood oils on planktonic cells and sessile, and also, tests of sanitizing solutions in based oils on coupons with biofilm of C. sakazakii. The in vitro antimicrobial activity test was performed based on the broth microdilution technique, followed by standard plate count in tryptone soya agar (TSA), thus, obtaining the MBC (minimum bactericidal concentration) for planktonic and sessile cells and formulation of sanitizing solutions based on essential oils to be tested in the biofilm formed in polypropylene coupon. Among the essential oils tested in the planktonic cells, cinnamon had the best result with MBC 0,125%. In the synergism study there was no growth at all tested combinations. There was an increase of MBC for sessile cells, cinnamon and mint presented 1% and ho wood 2%. It was also not observed bacterial growth in the study of synergism oils on sessile cells. For the test performed in polypropylene coupon, the treatment 1 (67% of cinnamon oil, 17% of ho wood oil, 17% of mint oil) was better for the time of 10 minutes contact and, to 20 minutes of contact, the control 2 (Sandet) was more effective.