Leitão Miguel M, Vieira Tatiana F, Sousa Sérgio F, Borges Fernanda, Simões Manuel, Borges Anabela
LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal; ALICE-Associate Laboratory for Innovation in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465, Porto, Portugal; CIQUP-IMS-Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal.
LAQV/REQUIMTE, BioSIM-Department of Biomedicine, Faculty of Medicine, University of Porto, Rua Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal.
Microb Pathog. 2024 Jun;191:106663. doi: 10.1016/j.micpath.2024.106663. Epub 2024 Apr 26.
Quorum sensing (QS) has a central role in biofilm lifestyle and antimicrobial resistance, and disrupting these signaling pathways is a promising strategy to control bacterial pathogenicity and virulence. In this study, the efficacy of three structurally related benzaldehydes (4-hydroxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde (vanillin) and 4-hydroxy-3,5-dimethoxybenzaldehyde (syringaldehyde)) in disrupting the las and pqs systems of Pseudomonas aeruginosa was investigated using bioreporter strains and computational simulations. Additionally, these benzaldehydes were combined with tobramycin and ciprofloxacin antibiotics to evaluate their ability to increase antibiotic efficacy in preventing and eradicating P. aeruginosa biofilms. To this end, the total biomass, metabolic activity and culturability of the biofilm cells were determined. In vitro assays results indicated that the aromatic aldehydes have potential to inhibit the las and pqs systems by > 80 %. Molecular docking studies supported these findings, revealing the aldehydes binding in the same pocket as the natural ligands or receptor proteins (LasR, PQSA, PQSE, PQSR). Benzaldehydes were shown to act as virulence factor attenuators, with vanillin achieving a 48 % reduction in pyocyanin production. The benzaldehyde-tobramycin combination led not only to a 60 % reduction in biomass production but also to a 90 % reduction in the metabolic activity of established biofilms. A similar result was observed when benzaldehydes were combined with ciprofloxacin. 4-Hydroxybenzaldehyde demonstrated relevant action in increasing biofilm susceptibility to ciprofloxacin, resulting in a 65 % reduction in biomass. This study discloses, for the first time, that the benzaldehydes studied are potent QS inhibitors and also enhancers of antibiotics antibiofilm activity against P. aeruginosa.
群体感应（QS）在生物膜生活方式和抗菌耐药性中起着核心作用，破坏这些信号通路是控制细菌致病性和毒力的一种有前景的策略。在本研究中，使用生物报告菌株和计算模拟研究了三种结构相关的苯甲醛（4-羟基苯甲醛、4-羟基-3-甲氧基苯甲醛（香草醛）和4-羟基-3,5-二甲氧基苯甲醛（丁香醛））对铜绿假单胞菌las和pqs系统的破坏作用。此外，将这些苯甲醛与妥布霉素和环丙沙星抗生素联合使用，以评估它们在预防和根除铜绿假单胞菌生物膜方面提高抗生素疗效的能力。为此，测定了生物膜细胞的总生物量、代谢活性和可培养性。体外试验结果表明，芳香醛有潜力抑制las和pqs系统达80%以上。分子对接研究支持了这些发现，揭示了醛类与天然配体或受体蛋白（LasR、PQSA、PQSE、PQSR）结合在同一口袋中。苯甲醛被证明可作为毒力因子减弱剂，香草醛使绿脓菌素产量降低48%。苯甲醛-妥布霉素组合不仅使生物量产量降低60%，还使成熟生物膜的代谢活性降低90%。当苯甲醛与环丙沙星联合使用时也观察到类似结果。4-羟基苯甲醛在增加生物膜对环丙沙星的敏感性方面表现出相关作用，使生物量降低65%。本研究首次揭示，所研究的苯甲醛是有效的群体感应抑制剂，也是抗生素抗铜绿假单胞菌生物膜活性的增强剂。
