Controlling Staphylococcus aureus biofilm on food contact surfaces: the efficacy of Oliveria decumbens essential oil and its implications on biofilm-related genes.

Abstract

Aims: This study aimed to investigate the effect of Oliveria decumbens essential oil (Od-EO) on the phenotypic properties and gene expression of Staphylococcus aureus biofilm on commonly used food contact surfaces.

Methods and results: The minimum inhibitory concentration and minimum bactericidal concentration of Od-EO on S. aureus ATCC25923 were determined to be 0.5 and 1 µl/ml, respectively. Crystal violet staining, scanning electron microscopy (SEM), biofilm metabolic activity evaluation, and real-time PCR analysis were used to assess the anti-biofilm properties of Od-EO. The results demonstrated that Od-EO exhibited significant anti-biofilm properties against S. aureus and effectively reduced the metabolic activity of biofilm cells. Furthermore, the inhibitory effects of Od-EO on biofilm formation were more pronounced on stainless steel (SS) compared to high-density polyethylene (HDPE) surfaces. Real-time PCR analysis revealed that Od-EO downregulated the expression of biofilm-related genes (icaA, icaD, clfA, clfB, FnbA, FnbB, and hld) in S. aureus grown on SS, while the expression levels of all studied genes except hld in the biofilm formed on HDPE remained unchanged or increased.

Conclusions: One of the main anti-biofilm mechanisms of the Od-EO on the HDPE is related to the disturbance in the QS of the cells. These findings highlight the potential of Od-EO as an effective agent for controlling and inhibiting S. aureus biofilm in the food industry and its potential use in disinfectant compounds.