牛源金黄色葡萄球菌感染小鼠后药物敏感性变化及其诱导的氧化应激

Resistance Change and Oxidative Stress-induced After Infecting Mice with Staphyloccocus aureus Isolated from Bovine

为探讨牛源金黄色葡萄球菌感染小鼠前后对抗菌药物的抗性变化以及该菌感染小鼠后对其肝脏、肾脏和脾脏组织的氧化功能的影响,将20只昆明小鼠随机分为2组,分别为空白对照组和牛源金黄色葡萄球菌感染组。采用纸片扩散法(K-B法)分别对试验菌(感染前)和分离菌(感染后)进行药敏试验;采用比色法分别测定肝脏、肾脏和脾脏组织的总抗氧化能力(T-AOC)与脂质过氧化产物(TBARS),并进行统计学分析。结果显示,分别从感染组小鼠的肾脏和脾脏中分离出金黄色葡萄球菌,肝脏中未分离出。洁霉素、万古霉素、阿莫西林、链霉素、新霉素、庆大霉素、先锋霉素、氨苄西林、强力霉素、氟氧头孢、复方新诺明、四环素、红霉素、卡那霉素、氟苯尼考、恩诺沙星、诺氟沙星和磺胺异噁唑18种药物对分离菌的抑菌圈直径显著小于对试验菌的相应抑菌圈直径(P<0.01),18种药物对感染后肾脏和脾脏的分离菌的相应抑菌圈直径差异均不显著;试验菌和分离菌对青霉素G和杆菌肽不敏感,而对其他18种药物均显示为高度敏感;金黄色葡萄球菌感染小鼠10d后,与空白对照组相比,感染组小鼠的肝脏、肾脏和脾脏组织的T-AOC均显著降低(P<0.01),而相应组织中的TBARS均显著升高(P<0.01)。结果表明,从感染组肾脏和脾脏组织中分离出的金黄色葡萄球菌较感染前对抗菌药物的抗性会增强;牛源金黄色葡萄球菌感染小鼠后能诱导肝脏、肾脏和脾脏组织处于氧化应激状态。

To investigate the resistance change of Staphyloccocus aureus after infecting mice and the effect of S.aureus on total antioxidant capacity of liver,kidney and spleen in mice,twenty adult mice were divided into control group and S.aureusinfected group randomly.The resistance of the test strain（before the infection）and the isolated strain（after the infection）were detected by disc diffusion method,and the activity of total antioxidant capacity（T-AOC）and the content of thiobarbituric acid reacting substances（TBARS）produced from lipid peroxidation were measured by colorimetry and analyzed statistically.The results showed that S.aureus could be isolated from kidney and spleen,but not liver in mice after infection.When the isolates from kidney and spleen compared with the test bacteria,the antibacterial circle diameters decreased significantly in drugs of lincomycin,vancomycin,amoxicillin,streptomycin,neomycin,gentamicin,cephalosporin,ampicillin,doxycycline,flomoxef sodium,sulfamethoxazole compound,tetracycline,erythromycin,kanamycin,florfenicol,enrofloxacin,norfloxacin and sulphonamides（P0.01）,no significant difference was observed between kidney and spleen in the same drug tereatment.In both of penicillin G and bacitracin,the antibacterial circle diameters were zero,and no significant difference between kidney and spleen were observed.In addition,both of the test strain and the isolated strain were completely not sensitive to penicillin G and bacitracin,but sensitive to the other 18 drugs.Moreover,significant reduction（P0.01）in the activity levels of total antioxidant capacity accompanied by a significant increase（P0.01）in the lipid peroxidation products in the liver,kidney and spleen in bacterial infected mice over controls.Thus,the results suggest that the resistance of S.aureus isolated from kidney and spleen in mice will enhance after the infection,and S.aureus isolated from bovine can induce oxidative stress in the liver,kidney and spleen of mice.