THE ANTIBACTERIAL MODE OF ACTION OF LINALOOL AGAINST SALMONELLA

Greater consumer awareness and concern regarding synthetic chemical additives have led producers to control microbial spoilage and hazards by the use of natural preservatives such as plant essential oils. However, usage of these compounds without sufficient knowledge about their influence on bacteria may provoke the emergence of resistant human pathogens, as we have previously demonstrated with Salmonella Senftenberg that has developed resistance to basil oil and its major constituent linalool.

Herein, the antimicrobial mode of action of linalool against S. Senftenberg was investigated. We have found that linalool perforated the bacterial membrane of S. Senftenberg, resulting in increased permeability of both membranes and leakage of vital molecules. Linalool also inhibited cell motility and caused aggregation. A multi-step exposure of S. Senftenberg to linalool developed a resistant mutant not only to linalool but also to basil oil and several antibiotics. This mutant demonstrated less permeability to linalool, defected motility, higher aggregation percentages and larger aggregate mean size upon incubation with linalool.

Interestingly, we found that the linalool-induced aggregation is mediated by secreted proteins and that linalool presence is not enough for aggregation to occur. This aggregation may indicate of a plausible adaptation to linalool through formation of clustering similar to biofilm arrangement.