摘要目的：比较不同耐药性鲍曼不动杆菌分泌的外膜泡（ OMVs）的毒力。方法提取、纯化4株不同耐药性鲍曼不动杆菌（菌株33、3237、B29和10）分泌的OMVs，BCA法定量后，使用不同浓度的OMVs刺激RAW264．7细胞24 h，CCK-8试剂检测OMVs的细胞毒性，q-PCR法检测细胞因子，包括肿瘤坏死因子（TNF）-α、白细胞介素（IL）-6、IL-1β、角化细胞源性生长因子（KC）和巨噬细胞炎性蛋白2（MIP-2）的表达，并采用单因素方差分析进行统计学比较。结果药敏试验结果显示，菌株10为泛耐药鲍曼不动杆菌（XDRAB），菌株B29为多重耐药鲍曼不动杆菌（MDRAB），而菌株33和3237为非MDRAB。将不同浓度OMVs与RAW264．7细胞共孵育24 h后，细胞存活率随着OMVs浓度增加而降低。其中，菌株10、B29、3237产生的OMVs在5μg／mL时可引起明显的细胞死亡，而菌株33产生的OMVs毒力明显低于其他菌株，在25μg／mL时细胞存活率仍未见明显降低。4株鲍曼不动杆菌分泌的OMVs均能刺激RAW264．7细胞分泌细胞因子TNF-α、IL-6、IL-1β、KC和MIP-2，且随着OMVs浓度增加，细胞因子的表达水平也增加。菌株33分泌的OMVs促炎能力最低，菌株10分泌的OMVs促炎能力最高，且在5μg／mL时，菌株10产生的OMVs促进KC、MIP-2表达的能力急剧上升，明显高于其他菌株（F＝19．094和19．032，P＜0．05或＜0．01）。结论不同耐药性鲍曼不动杆菌分泌的OMVs毒力各不相同，其中泛耐药和多重耐药菌株分泌的OMVs具有较强的细胞毒力以及促炎能力。

abstractsObjective To compare the toxicity of outer membrane vesicles ( OMVs) secreted by Acinetobacter baumannii strains with different drug-resistance spectrums.Methods Four Acinetobacter baumannii strains with different drug-resistance spectrums were collected (strain 33, 3237, B29 and 10), and OMVs produced by these strains were extracted and purified.BCA assay was used to determine the protein concentrations, and RAW264.7 cells were incubated with different concentrations of OMVs for 24 h. Cell viability was measured with CCK-8 assay, and gene expression of tumor necrosis factor-alpha ( TNF-α) , interleukin-6 ( IL-6) , interleukin-1 beta ( IL-1β) , keratinocyte-derived chemokine ( KC) and macrophage&nbsp;inflammatory protein 2 (MIP-2) was assessed by quantitative real-time PCR.One-way ANOVA was used for data analysis.Results According to the result of drug susceptibility test, strain 10 was extensively drug-resistant Acinetobacter baumannii ( XDRAB ) strain, strain B29 was multi-drug resistance Acinetobacter baumannii (MDRAB) strain, while strain 33 and 3237 were non-MDRAB strains.After incubated with different concentrations of OMVs for 24 h, cell viability of RAW264.7 declined with the increase of OMVs concentrations.OMVs released from strain10, B29 and 3237 significantly lowered the cell viability at the concentration of 5 μg/mL, while the cytotoxicity of OMVs released from strain 33 was much weaker, and no remarkable decrease in cell viability was observed even at the concentration of 25 μg/mL.OMVs of all strains induced the release of TNF-α, IL-6, IL-1β, KC and MIP-2 in RAW264.7 cells, and the levels of theses cytokines were increased with the concentration of OMVs.Inflammatory response in cells incubated with OMVs from strain 33 was the weakest, while OMVs from strain 10 induced strongest inflammatory response.KC and MIP-2 levels were significantly higher in RAW264.7 cells incubated with OMVs from strain 10 with a concentration of 5 μg/mL than that incubated with OMVs from other strains ( F=19.094 and 19.032,P<0.05 or <0.01).Conclusions OMVs from Acinetobacter baumannii strains with different drug-resistance spectrums are of different toxicity.OMVs from XDRAB and MDRAB strains have higher toxicities and may induce stronger inflammatory response.