Non-thermal plasma (NTP), generated at atmospheric pressure by DC cometary discharge with a metallic grid, and antibiotics (gentamicin-GTM, ceftazidime-CFZ and polymyxin B-PMB), either alone or in combination, were used to eradicate the mature biofilm of Pseudomonas aeruginosa formed on Ti-6Al-4V alloy. Our aim was to find the conditions for NTP pre-treatment capable of enhancing the action of the antibiotics and thus reducing their effective concentrations. The NTP treatment increased the efficacy of relatively low concentrations of antibiotics. Generally, the highest effect was achieved with GTM, which was able to suppress the metabolic activity of pre-formed P. aeruginosa biofilms in the concentration range of 4-9 mg/L by up to 99%. In addition, an apparent decrease of biofilm-covered area was confirmed after combined NTP treatment and GTM action by SYTO®13 staining using fluorescence microscopy. Scanning electron microscopy confirmed a complete eradication of P. aeruginosa ATCC 15442 mature biofilm from Ti-6Al-4V alloy when using 0.25 h NTP treatment and subsequent treatment by 8.5 mg/L GTM. Therefore, NTP may be used as a suitable antibiofilm agent in combination with antibiotics for the treatment of biofilm-associated infections caused by this pathogen.

中文翻译：

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使用非热等离子体预处理来增强对成熟铜绿假单胞菌生物膜的抗生素作用

非热等离子体 (NTP)，由直流彗星放电与金属网格在大气压下产生，和抗生素（庆大霉素-GTM、头孢他啶-CFZ 和多粘菌素 B-PMB），单独或组合使用，用于根除成熟的铜绿假单胞菌在 Ti-6Al-4V 合金上形成的生物膜。我们的目标是找到能够增强抗生素作用并因此降低其有效浓度的 NTP 预处理条件。NTP 处理增加了相对低浓度抗生素的功效。一般来说，GTM 达到了最高的效果，它能够在 4-9 mg/L 的浓度范围内抑制预形成的铜绿假单胞菌生物膜的代谢活性高达 99%。此外，结合 NTP 处理和 GTM 作用后，通过使用荧光显微镜的 SYTO®13 染色证实了生物膜覆盖面积的明显减少。扫描电子显微镜证实，当使用 0.25 小时 NTP 处理和随后使用 8.5 mg/L GTM 处理时，可完全根除 Ti-6Al-4V 合金中的铜绿假单胞菌 ATCC 15442 成熟生物膜。因此，NTP 可作为合适的抗生物膜剂与抗生素联合用于治疗由该病原体引起的生物膜相关感染。