Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, 202002, UP, India.
Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, 202002, UP, India.
Microb Pathog. 2024 Dec;197:107097. doi: 10.1016/j.micpath.2024.107097. Epub 2024 Nov 1.
Multidrug resistance (MDR) Gram-negative bacteria are increasingly resistant to multiple antibiotics, posing a serious challenge to infection control and treatment. Combining plant-derived bioactives with antibiotics offers a promising approach to overcome the challenges posed by MDR pathogens like Pseudomonas aeruginosa. This study investigated the synergistic effects of Cinnamomum verum with beta-lactam and fluoroquinolones against P. aeruginosa PAO1. The ethyl acetate fraction of C. verum (CVEF) was obtained through fractionation in organic solvents with progressively higher polarity. The interaction of CVEF with selected antibiotics was assessed by checkerboard synergy assay. The effects of synergistic combinations on pyocyanin, pyoverdine, protease, EPS production, and biofilm development were measured using spectroscopic assays. CVEF combined with cefepime, ceftazidime, and levofloxacin significantly enhanced antibacterial efficacy with FICIs between 0.156 and 0.5. The most active combinations i.e., CVEF-cefepime and CVEF-ceftazidime inhibited viable cell count of growth by 3.6 and 4.2 log CFU/ml respectively. The combination also inhibited virulence factors (>75 %) and biofilms (>80 %) at lower 1/2 × FICs. The viable count of biofilm cells was also reduced from 6.4 to 3.3 and 3.6 log CFU/ml. Membrane permeability was decreased by 60.34 % and biofilm cell viability by 22.53-38.44 %. Key phytochemicals analyzed by GC/MS and LC/MS/MS, include cinnamaldehyde, trans-chlorogenic acid, quercetin, and quercetin 3'-O-glucuronide. In molecular docking investigations, quercetin 3'-O-glucuronide had the highest binding affinity with quorum sensing (QS) and biofilm-associated protein. The findings suggest CVEF, in combination with antibiotics, effectively targets resistance phenotypes of P. aeruginosa, impairing growth, virulence, and biofilms. This supports further research into natural compounds alongside antibiotics to treat drug-resistant infections.
多药耐药（MDR）革兰氏阴性菌对多种抗生素的耐药性日益增强，对感染控制和治疗构成严重挑战。将植物衍生的生物活性物质与抗生素结合使用是克服铜绿假单胞菌等 MDR 病原体带来的挑战的一种有前途的方法。本研究调查了肉桂与β-内酰胺类和氟喹诺酮类药物联合使用对铜绿假单胞菌 PAO1 的协同作用。通过在有机溶剂中进行分级分离获得肉桂的乙酸乙酯级分（CVEF），有机溶剂的极性逐渐增加。通过棋盘协同试验评估 CVEF 与选定抗生素的相互作用。通过光谱分析测定协同组合对绿脓菌素、吡咯菌素、蛋白酶、EPS 产生和生物膜形成的影响。CVEF 与头孢吡肟、头孢他啶和左氧氟沙星联合使用时，FICI 在 0.156 至 0.5 之间显著增强了抗菌效果。最有效的组合，即 CVEF-头孢吡肟和 CVEF-头孢他啶，分别使生长的活菌计数减少了 3.6 和 4.2 对数 CFU/ml。该组合还以较低的 1/2×FIC 抑制了毒力因子（>75%）和生物膜（>80%）。生物膜细胞的活菌计数也从 6.4 减少到 3.3 和 3.6 对数 CFU/ml。膜通透性降低了 60.34%，生物膜细胞活力降低了 22.53%-38.44%。通过 GC/MS 和 LC/MS/MS 分析的关键植物化学物质包括肉桂醛、反式-绿原酸、槲皮素和槲皮素 3'-O-葡萄糖苷。在分子对接研究中，槲皮素 3'-O-葡萄糖苷与群体感应（QS）和生物膜相关蛋白具有最高的结合亲和力。研究结果表明，CVEF 与抗生素联合使用可有效靶向铜绿假单胞菌的耐药表型，抑制其生长、毒力和生物膜形成。这支持进一步研究天然化合物与抗生素联合治疗耐药感染。
