背景：苍术在中医中广泛用于皮肤和胃肠道疾病的治疗。其活性成分已被证明具有许多有益的特性，包括抗菌，抗病毒，抗炎,抗肿瘤，和抗溃疡活性。此外，据报道，苍术挥发油（VOAR）可以有效抑制和根除金黄色葡萄球菌等病原体，大肠杆菌和白色念珠菌。特别值得关注的是假中间葡萄球菌,导致犬脓皮病的主要病原体，其日益增长的抗菌素耐药性构成了严重的公共卫生威胁。VOAR值得进一步研究其对假中介葡萄球菌的抗菌潜力。
目的：本研究旨在验证VOAR对假中介葡萄球菌的体外抗菌活性。并建立小鼠浅表皮肤感染模型，评估VOAR的体内治疗效果。
方法：从脓皮病犬中分离出30株假中介杆菌，并采用纸片扩散法进行耐药性分析。通过肉汤稀释法测定VOAR的最低抑菌浓度(MIC)和最低杀菌浓度(MBC)。使用UV分光光度计监测细菌在含有VOAR的培养基中的生长曲线。采用扫描电子显微镜观察了VOAR对假中间菌微观结构的影响。使用圆盘扩散法评估VOAR对假中介链球菌抗生素耐药性的影响。20只小鼠随机分为4组:对照组,生理盐水组,VOAR集团,和阿米卡星组。除了对照组,小鼠的皮肤屏障被水龙头剥离破坏，随后给小鼠接种假中介链球菌，建立浅表皮肤感染模型。模型小鼠用生理盐水处理,VOAR,和阿米卡星5天。在治疗期之后，根据体重的测量来评估每组的治疗效果，皮肤症状,组织细菌负荷，组织IL-6含量，和组织病理学变化。
结果：发现VOAR对30个假中介链球菌临床分离株的MIC和MBC分别为0.005425%和0.016875%，分别。VOAR可以表现出延迟细菌进入对数生长期的能力，破坏细菌结构,并与抗生素药物一起增强抗菌区。在浅表皮肤感染模型小鼠中,VOAR显着降低了皮肤发红的评分（P<0.0001），结痂形成(P<0.0001),和皱纹（P<0.0001）。此外，VOAR显著降低小鼠皮肤组织中的细菌负荷(P<0.001)和IL-6含量(P<0.0001)。组织病理学观察显示，VOAR组的全层皮肤结构更完整，更清晰的皮肤层，与其他组相比，炎性细胞浸润和成纤维细胞增殖显着改善。
结论：结果表明，VOAR在体外能有效抑制和根除假中间葡萄球菌，同时还能增强病原菌对抗生素的敏感性。此外，VOAR在浅表皮肤感染模型小鼠中表现出明显的治疗效果。
BACKGROUND: Atractylodis Rhizoma is extensively employed in Traditional Chinese Medicine for the treatment of skin and gastrointestinal ailments. Its active components have been proven to demonstrate numerous beneficial properties, including antibacterial, antiviral, anti-inflammatory, anti-tumor, and anti-ulcer activities. Furthermore, the volatile oil from Atractylodis Rhizoma (VOAR) has been reported to effectively inhibit and eradicate pathogens such as Staphylococcus aureus, Escherichia coli and Candida albicans. Of particular concern is Staphylococcus pseudintermedius, the predominant pathogen responsible for canine pyoderma, whose increasing antimicrobial resistance poses a serious public health threat. VOAR merits further investigation regarding its antibacterial potential against Staphylococcus pseudintermedius.
OBJECTIVE: The study aims to verify the in vitro antibacterial activity of VOAR against Staphylococcus pseudintermedius. And a superficial skin infection model in mice was established to assess the in vivo therapeutic effect of VOAR.
METHODS: Thirty strains of S. pseudintermedius were isolated from dogs with pyoderma, and the drug resistance was analyzed by disc diffusion method. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of VOAR were determined through the broth dilution method. The growth curve of bacteria in a culture medium containing VOAR was monitored using a UV spectrophotometer. Scanning electron microscopy was employed to observe the effects of VOAR on the microstructure of S. pseudintermedius. The impact of VOAR on the antibiotic resistance of S. pseudintermedius was assessed using the disc diffusion method. Twenty mice were randomly divided into four groups: the control group, the physiological saline group, the VOAR group, and the amikacin group. With the exception of the control group, the skin barrier of mice was disrupted by tap stripping, and the mice were subsequently inoculated with S. pseudintermedius to establish a superficial skin infection model. The modeled mice were treated with normal saline, VOAR, and amikacin for 5 days. Following the treatment period, the therapeutic effect of each group was evaluated based on the measures of body weight, skin symptoms, tissue bacterial load, tissue IL-6 content, and histopathological changes.
RESULTS: The MIC and MBC of VOAR against 30 clinical isolates of S. pseudintermedius were found to be 0.005425% and 0.016875%, respectively. VOAR could exhibit the ability to delay the entry of bacteria into the logarithmic growth phase, disrupt the bacterial structure, and enhance the antibacterial zone in conjunction with antibiotic drugs. In the superficial skin infection model mice, VOAR significantly reduced the scores for skin redness (P < 0.0001), scab formation (P < 0.0001), and wrinkles (P < 0.0001). Moreover, VOAR markedly reduced the bacterial load (P < 0.001) and IL-6 content (P < 0.0001) in the skin tissues of mice. Histopathological observations revealed that the full-layer skin structure in the VOAR group was more complete, with clearer skin layers, and showed significant improvement in inflammatory cell infiltration and fibroblast proliferation compared to other groups.
CONCLUSIONS: The results demonstrate that VOAR effectively inhibits and eradicates Staphylococcus pseudintermedius in vitro while also enhancing the pathogen\'s sensitivity to antibiotics. Moreover, VOAR exhibits a pronounced therapeutic effect in the superficial skin infection model mice.
