In vitro antibacterial and antibiofilm effects of cold atmospheric microwave plasma against Pseudomonas aeruginosa causing canine skin and ear infections

Background Pseudomonas aeruginosa is an opportunist pathogen that causes purulent inflammation in the skin and in the ears of dogs. Among the various virulence factors of P. aeruginosa, biofilms have been reported to result in antibiotic resistance, leading to therapeutic limitations. Cold atmospheric microwave plasma (CAMP) is known to have a high antimicrobial effect, which causes physical cell wall rupture and DNA damage. Hypothesis/Objectives The objective of this study was to evaluate the antibacterial and antibiofilm effects of CAMP against planktonic bacteria and the biofilm of P. aeruginosa. Methods and materials The antibacterial effect of CAMP against P. aeruginosa ATCC10145 and clinical isolates (n = 30) was evaluated using the colony count method. We also assessed the effect of CAMP on biofilm of P. aeruginosa ATCC strain by the colony count method, water‐soluble tetrazolium salt (WST) assay and confocal laser scanning microscopy (CLSM). Results The complete eradication of P. aeruginosa (ATCC strain and clinical isolates) was achieved within 120 s at 50 W, and clinical isolates required 60 s shorter than the ATCC strain for complete eradication at 50 W. We also confirmed the time‐dependent bactericidal effect of CAMP at 50 W against ATCC strain biofilm. Conclusions and clinical importance CAMP was effective against both planktonic bacteria and biofilm formation of P. aeruginosa. However, further studies on in vivo efficacy and safety in canine skin and ears are necessary to fully validate its clinical application. 摘要 背景‐铜绿假单胞菌是一种条件致病菌, 可引起犬皮肤和耳部化脓性炎症。在铜绿假单胞菌的各种毒力因子中, 有报道生物膜导致抗生素耐药, 限制了疗效。已知冷大气微波等离子体(CAMP)具有较高的抗菌作用, 从而引起物理细胞壁破裂和DNA损伤。 假设/目的‐本研究的目的是评价CAMP对浮游细菌和铜绿假单胞菌生物膜的抗菌和抗生物膜作用。 方法和材料‐使用菌落计数法评价CAMP对铜绿假单胞菌ATCC10145和临床分离株(n = 30)的抗菌作用。我们还通过菌落计数法、水溶性四唑盐(WST)试验和激光共聚焦显微镜(CLSM)评估了CAMP对铜绿假单胞菌ATCC菌株生物膜的影响。 结果‐铜绿假单胞菌 (ATCC菌株和临床分离株) 在50 W下120 s内完全根除, 在50 W下,临床分离株完全根除所需时间比ATCC菌株短60 s。我们还证实了50 WCAMP对ATCC菌株生物膜的时间依赖性杀菌作用。 结论和临床重要性–CAMP对抑制浮游细菌和铜绿假单胞菌生物膜形成均有效。但有必要对犬皮肤和耳部的体内疗效和安全性进行进一步研究, 以充分验证其临床应用。 Résumé Contexte Pseudomonas aeruginosa est un pathogène opportuniste qui provoque une inflammation purulente de la peau et des oreilles des chiens. Parmi les différents facteurs de virulence de P. aeruginosa, il a été rapporté que les biofilms entraînent une résistance aux antibiotiques, entraînant des limitations thérapeutiques. Le CAMP (Cold atmospheric microwave plasma) est connu pour avoir un effet antimicrobien élevé, ce qui provoque une rupture physique de la