Diallyl disulfide, the antibacterial component of garlic essential oil, inhibits the toxicity of Bacillus cereus ATCC 14579 at sub-inhibitory concentrations

This study aimed to investigate the effects of diallyl disulfide (DADS), from garlic essential oil, on the toxicity of Bacillus cereus at sub-inhibitory concentrations (?60 ?g/mL). The bacterial growth curve, enterotoxin production, biofilm formation, and swarming motility of B. cereus were monitored under DADS pressure, and quantitative RT-PCR unveiled the expression of essential genes. Following treatment with DADS, the production of the enterotoxins Nhe and Hbl, as well as total biofilm formation and swarming ability, showed a decreasing trend with the concentration. DADS down-regulated the transcription of plcR, which is involved in the quorum sensing system of B. cereus, as well as the pleiotropic regulator genes codY and rpoN, thus restricting the expression of the genes related to enterotoxins, biofilms, and motility. Meanwhile, sinR was up-regulated to inhibit the production of biofilms. Thus, DADS inhibited the virulence factors of B. cereus at a sub-inhibitory concentration by inactivating the transcription of key pleiotropic regulator genes, and, therefore, this compound appears to have great potential in the prevention and control of B. cereus.