Luo Shuangyan, Kang Xinyun, Luo Xiaofeng, Li Caixia, Wang Guiqin
School of Agriculture, Ningxia University, 750021, Yinchuan, China.
School of Agriculture, Ningxia University, 750021, Yinchuan, China.
Microb Pathog. 2023 Sep;182:106274. doi: 10.1016/j.micpath.2023.106274. Epub 2023 Jul 27.
The potential effects of quercetin and gentamicin combination on the bacteriostatic activity and biofilm formation of Pseudomonas aeruginosa (PA) were examined, and the findings provided a theoretical basis for the development of quercetin as a new biofilm inhibitor.
The minimum inhibitory concentration (MIC) of eight PAs was determined by microdilution method and the partial inhibitory concentration index (FICI) of the combined drug was analyzed by micro-dilution method. Thereafter, the lowest film inhibitory concentration (MBIC) of quercetin and gentamicin alone and in combination was evaluated by crystal violet staining. Finally, scanning electron microscopy (SEM) and laser confocal microscopy (CLSM) were used to decipher the inhibitory effect of the combination on biofilm formation.
The antibacterial activity of quercetin alone was relatively weak, but after combination with gentamicin, the antibacterial activity was significantly enhanced, as evident by FICI of 0.28 and 0.53 and manifested as synergistic or additive effect, which indicated that quercetin can enhance gentamicin antibacterial activity. The results of crystal violet staining revealed that quercetin and gentamicin alone exhibited a similar biofilm formation inhibitory effect, but the inhibitory effect was substantially weaker, and the antibiofilm activity was stronger and exhibited a dose-dependent response after the combination of the two with 1/2FICI. The results of scanning electron microscopy and laser confocal microscopy also showed that the treatment of PA biofilm after combining quercetin and gentamicin with 1/2FICI could completely destroy the spatial structure of the complete biofilm, significantly reduce the thickness of bacteria, and markedly reduce the proportion of viable bacteria in the membrane.
The combination of quercetin and gentamicin can effectively inhibit the formation of PA as well as its biofilm, and exhibit synergistic and additive effects.
研究槲皮素与庆大霉素联合应用对铜绿假单胞菌（PA）抑菌活性及生物膜形成的潜在影响，为槲皮素作为新型生物膜抑制剂的开发提供理论依据。
采用微量稀释法测定8株PA的最低抑菌浓度（MIC），并通过微量稀释法分析联合用药的部分抑菌浓度指数（FICI）。此后，采用结晶紫染色法评估槲皮素和庆大霉素单独及联合应用时的最低生物膜抑制浓度（MBIC）。最后，利用扫描电子显微镜（SEM）和激光共聚焦显微镜（CLSM）来解读联合用药对生物膜形成的抑制作用。
槲皮素单独的抗菌活性相对较弱，但与庆大霉素联合后，抗菌活性显著增强，FICI分别为0.28和0.53，表现为协同或相加作用，这表明槲皮素可增强庆大霉素的抗菌活性。结晶紫染色结果显示，槲皮素和庆大霉素单独应用时对生物膜形成的抑制作用相似，但抑制作用明显较弱，二者以1/2FICI联合后抗生物膜活性更强且呈剂量依赖性反应。扫描电子显微镜和激光共聚焦显微镜的结果还表明，槲皮素和庆大霉素以1/2FICI联合处理PA生物膜后，可完全破坏完整生物膜的空间结构，显著降低细菌厚度，并明显降低膜内活菌比例。
槲皮素与庆大霉素联合可有效抑制PA及其生物膜的形成，并呈现协同和相加作用。
