Drug-resistant biofilm producer A. baumannii isolates are a global concern that warns researchers about the development of new treatments. This study was designed to analyze the effect of photodynamic therapy (PDT) as monotherapy and associated with melittin on multidrug-resistant A. baumannii isolates. Sub-lethal doses of photosensitizer, LED, and PDT were determined. The PDT effect on the biofilm and expression of biofilm-associated genes was evaluated by scanning electron microscopy and quantitative real-time PCR (qRT-PCR) methods, respectively. The synergistic effect of PDT and melittin on the survival of MDR/XDR strong biofilm producer isolates was evaluated by checkerboard assay. Survival rates were significantly decreased at the lowest concentration of 12.5–50 μg/ml in 4 min at an energy density of 93.75 J/cm² (P < 0.05). The optimized PDT method had a bactericidal effect against all tested groups, and the mean expression levels of csu, abaI, bap, and ompA genes in the strong biofilm producers were decreased significantly compared to the control group. The combined effect of LED and melittin successfully reduced the MDR/XDR A. baumannii strong biofilm producers' growth from 3.1 logs. MB-mediated aPDT and combined treatment of PDT with melittin, which has been investigated for the first time in this study, can be an efficient strategy against MDR/XDR A. baumannii isolates with strong biofilm production capacity.

耐药生物膜产生者鲍曼不动杆菌分离株是一个全球性的问题，它对研究人员新疗法的开发提出了警告。本研究旨在分析光动力疗法（PDT）作为单一疗法以及与蜂毒肽联用对多重耐药鲍曼不动杆菌分离株的效果。确定了光敏剂、LED 和 PDT 的亚致死剂量。分别通过扫描电子显微镜和定量实时PCR（qRT-PCR）方法评估PDT对生物膜和生物膜相关基因表达的影响。通过棋盘试验评估 PDT 和蜂毒肽对 MDR/XDR 强生物膜产生菌株存活的协同作用。^{在能量密度为 93.75 J/cm 2}的最低浓度 12.5–50 μg/ml 4 分钟内，存活率显着降低（P  < 0.05）。优化后的PDT方法对所有测试组均具有杀菌作用，强生物膜产生组中csu、abaI、bap和ompA基因的平均表达水平较对照组显着降低。LED 和蜂毒肽的联合作用成功地将 MDR/XDR鲍曼不动杆菌强生物膜生产者的生长从 3.1 对数降低。本研究首次研究了MB介导的aPDT和PDT与蜂毒肽联合治疗，可以成为针对具有强大生物膜生产能力的MDR/XDR鲍曼不动杆菌分离株的有效策略。