Given that Staphylococcus aureus, an opportunistic pathogen, is one of the main etiological agents that causes various hospital and community infections associated with the production of virulence factors, emerging treatment strategies target to attenuate the activity of these factors can be promising to combat antibiotic-resistant strains. In this perspective, we investigated the antipathogenic potential against three S. aureus strains of chloroform extracts of cell-free culture supernatant from the probiotic bacteria Lactobacillus casei and Lactobacillus acidophilus, as well as its suitability as an alternative antimutagenic agent. Both extracts did not display antibacterial activity but significantly reduced the bacterial biofilm formation at different stages 3 h (up to 73%), 6 h (up to 45%), and 24 h (up to 46%). Moreover, the extracts decrease the virulence factors production, hemolysin (up to 67%), and coagulase (delayed coagulation), as well as the cell metabolism in the biofilm (up to 65%), disrupting a preformed biofilm (up to 46%), all devoid of affecting its growth suggesting that the inhibition could be mediated by Quorum sensing (QS). The extract’s effect on biofilm disruption and metabolic activity seems to be strain dependent. The 2,5-diketopiperazines present in the extracts showed the ability to bind to the QS regulatory proteins SarA and AgrA in molecular docking studies. In the mutagenicity assay, both probiotic bacteria were able to remove the mutagen, and this capacity increased with the bacteria concentration.

鉴于金黄色葡萄球菌是一种机会性病原体，是导致与毒力因子产生相关的各种医院和社区感染的主要病原体之一，旨在减弱这些因子活性的新兴治疗策略有望对抗抗生素耐药性菌株。从这个角度来看，我们研究了来自益生菌干酪乳杆菌和嗜酸乳杆菌的无细胞培养上清液的氯仿提取物的三种金黄色葡萄球菌菌株的抗病原体潜力，以及它作为替代抗诱变剂的适用性。两种提取物均未显示抗菌活性，但在 3 小时（高达 73%）、6 小时（高达 45%）和 24 小时（高达 46%）的不同阶段显着减少了细菌生物膜的形成。此外，提取物减少毒力因子的产生、溶血素（高达 67%）和凝固酶（延迟凝固）以及生物膜中的细胞代谢（高达 65%），破坏预先形成的生物膜（高达 46%） )，均不影响其生长，表明抑制作用可能是由群体感应介导的(QS)。提取物对生物膜破坏和代谢活动的影响似乎与应变有关。提取物中存在的 2,5-二酮哌嗪在分子对接研究中显示出与 QS 调节蛋白 SarA 和 AgrA 结合的能力。在诱变试验中，两种益生菌都能够去除诱变剂，并且这种能力随着细菌浓度的增加而增加。