蜂胶对金黄色葡萄球菌α-溶血素的抑制作用

通过吸光度测量和荧光定量PCR的方法,在体外检测亚抑菌浓度的蜂胶作用下金黄色葡萄球菌α-溶血素活力变化及agrA、hla的mRNA表达量。结果显示,不同浓度蜂胶对金黄色葡萄球菌α-溶血素有不同程度的抑制作用（P〈0.05）;同时荧光定量PCR检测agrA和hla基因表明,蜂胶能够显著减少agrA和hla mRNA的相对表达量,进而抑制α-溶血素的表达。     

土木香提取物抑制金黄色葡萄球菌毒力因子分泌作用的研究

本研究旨在分析土木香提取物对金黄色葡萄球菌主要毒力因子分泌的影响及机制研究,以耐药性金黄色葡萄球菌USA 300为研究对象,通过醇提法获取土木香提取物,根据主要毒力因子蛋白表型功能(溶血活性和TNF-α含量释放分析),利用蛋白免疫印迹和荧光定量PCR分析检测不同浓度土木香提取物对金黄色葡萄球菌主要毒力因子分泌的影响及机制。无抗菌活性的土木香提取物与金黄色葡萄球菌共培养后可显著抑制培养物上清溶血活性及其诱导小鼠脾淋巴细胞TNF-α释放活性,蛋白免疫印迹分析表明,土木香提取物处理可显著降低金黄色葡萄球菌α-溶血素、肠毒素A和中毒休克综合征毒素-1(TSST-1)的分泌,荧光定量PCR试验结果进一步表明土木香提取物与金黄色葡萄球菌共培养后降低金黄色葡萄球菌α-溶血素、肠毒素A和TSST-1编码基因的转录及金黄色葡萄球菌二元调控系统agr的转录。本研究结果表明,土木香提取物通过抑制agr二元调控系统转录及其毒力因子编码基因的转录而降低毒力因子的分泌,土木香提取物是一种潜在的新型抗金黄色葡萄球菌感染先导化合物。     

5种中药提取物对金黄色葡萄球菌抑制作用的研究

采用水提,水浴加热的方法提取黄芩、黄连、黄柏、鱼腥草和五倍子五味中药的有效成分,通过二倍稀释法测出各个药的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),采用肉汤稀释棋盘法测定五味中药的联合抑菌情况。结果显示,金黄色葡萄球菌对黄连高度敏感;对黄芩、黄柏、五倍子和鱼腥草为中度敏感。黄芩、黄连和五倍子的杀菌作用较强,鱼腥草和黄柏的杀菌作用较弱。通过联合抑菌指数(FLCL)可知五倍子与黄芩、五倍子与黄连联合用药为协同作用。五倍子与鱼腥草、黄连与鱼腥草、黄连与黄芩的联合作用,表现为相加作用。黄连与黄柏、黄芩与鱼腥草、黄芩与黄柏、五倍子与黄柏的联合作用,表现为无关作用。鱼腥草与黄柏表现为拮抗作用。     

盐穗木提取物对金黄色葡萄球菌抑菌效果研究

为了解盐穗木提取物对金黄色葡萄球菌的抑菌效果,解决金黄色葡萄球菌耐药性的问题,笔者测定盐穗木乙醇提取物和正丁醇萃取物的抑菌圈直径、最低抑菌浓度(MIC)、最低杀菌浓度(MBC)及生长曲线。结果表明,盐穗木正丁醇萃取物的抑菌活性显著高于乙醇提取物,盐穗木乙醇提取物和盐穗木正丁醇萃取物的MIC分别为150.00 mg/mL和25.00 mg/mL,MBC分别为250.00 mg/mL和50.00 mg/mL。说明盐穗木正丁醇萃取物有良好的抑菌效果,可为新型抗菌药物的研发奠定基础。     

青霉素脂质体对耐药金黄色葡萄球菌的抑菌效果观察

本实验在国内首次观察了青霉素脂质体对耐药金黄色葡萄球菌的抑菌效果及其对外源性β－内酰胺酶的耐受性。结果：青霉素脂质体对耐药菌的最低抑菌浓度（ＭＩＣ）为２４０ＩＵ／ｍｌ，最低杀菌浓度（ＭＢＣ）为２６０ＩＵ／ｍｌ，游离青霉素的ＭＩＣ为１２００ＩＵ／ｍｌ，ＭＢＣ为１６００ＩＵ／ｍｌ；空白脂质体几乎无抑菌作用。青霉素脂质体对外源性β－内酰胺酶具有很强的耐受性。结果表明，青霉素制成脂质体制剂后可大大提高其对耐药菌株的抗菌能力，原因之一是它能保护青霉素免受β－内酰胺酶的水解破坏。     

金黄色葡萄球菌毒力及其免疫原性评价方法研究

为建立评价金黄色葡萄球菌毒力和用于筛选免疫保护性菌株的技术方法,选取小鼠腹腔攻毒方法确定的强毒力和弱毒力菌株各3株,经小鼠后腿肌肉注射不同剂量,比较20 d的临床病变差异,确定小鼠后腿内侧肌肉注射0.25 mL、OD600=0.6的剂量可以评价不同金黄色葡萄球菌的毒力。利用该方法比较了6株强毒力菌株的毒力差异,并用于2株免疫保护性菌株的筛选。结果证明建立的金黄色葡萄球菌毒力评价方法可以精确、客观比较不同菌株毒力差异,并可用于免疫保护性菌株的筛选。     

奶牛乳房炎金黄色葡萄球菌毒力因子及荚膜基因的PCR检测

为研究金黄色葡萄球菌(S.aureus)的因型特征,本实验利用聚合酶链式反(PCR)方法,对S.aureus的3个标准株和30个临床分离株的凝集因子A、凝固酶、溶血素等33种致病因子进行了检测.结果表明各分离株在毒力因子方面存在一定差异.这些差异的检测将为进一步研究S.aureus的致病性和有效防治提供参考.     

恩诺沙星和环丙沙星对金葡菌的抗菌后效应及抗菌后亚抑菌浓度效应

报告了抗菌后效应 (postantibiotic effect,PAE)、抗菌后亚抑菌浓度效应 (postantibiotic sub- MIC effect,PASME)、亚抑菌浓度效应 (sub- MIC effect,SME)研究的方法学和恩诺沙星、环丙沙星对金葡菌抗菌后效应及抗菌后亚抑菌浓度效应的研究结果。试验表明 :2、4MIC的恩诺沙星对金葡菌的 PAE为 1.0 3、1.5 0 h,1/2、1、2、4MIC的环丙沙星的 PAE为 0 .5 1、0 .88、1.47、1.92 h;1/8、1/4、1/2 MIC的恩诺沙星对经 4MIC药物诱导 1h的金葡菌可产生0 .38、1.15、>12 .31h的 PASME,1/8、1/4、1/2 MIC的环丙沙星的 PASME为 2 .6 9、>10 .17、>13.17h;1/8、1/4、1/2 MIC的恩诺沙星和环丙沙星对金葡菌产生的 SME分别为 0 .40、0 .91、>9.44 h和 0 .42、1.14、>9.0 2 h。上述结果说明 ,PAE、PASME和 SME的大小与药物浓度呈正相关 ,且环丙沙星比恩诺沙星对金葡菌有更长的效应     

7味蒙药对大肠杆菌和金黄色葡萄球菌体外抑菌试验研究

为筛选出对金黄色葡萄球菌（Staphylococcus aureus,S. aureus）和大肠杆菌（Escherichia coli,E. coli）具有良好抑菌作用的蒙药,试验采用打孔法测定S. aureus和E. coli对石榴皮、诃子、小白蒿、黄芩、黄芪、苦参、铁线莲7味蒙药敏感程度,微量稀释法测定蒙药的最小抑菌浓度（minimal inhibitory concentration,MIC）,棋盘法测定敏感蒙药对S. aureus和E. coli的协同指数（fractional inhibitory concentration index,FICI）。结果显示：石榴皮、诃子、黄芩3味蒙药对S. aureus的抑菌圈直径为23.30~32.60 mm,MIC为0.98~7.80 mg/mL;石榴皮、诃子、黄芩3味蒙药对E. coli的抑菌圈直径为5.20~12.50 mm,MIC为7.80~31.50 mg/mL;石榴皮与诃子联合用药对S. aureus的FICI为1.00,为相加作用;诃子与黄芩、石榴皮分别联合用药对E. coli的FICI都为0.75,为相加作用。综上所述,石榴皮、诃子、黄芩3味蒙药对S. aureus综合抑菌效果达极度敏感或高度敏感;石榴皮、诃子、黄芩3味蒙药对E. coli综合抑菌效果达极度敏感或高度敏感;在抑制S. aureus的配方中石榴皮、黄芩、诃子可被优先考虑;在抑制E. coli的配方中黄芩、诃子、石榴皮可被优先考虑。     

蜂胶对金黄色葡萄球菌毒力因子的抑制作用

金黄色葡萄球菌(简称金葡菌)是临床非常重要的致病菌之一,是引起奶牛和山羊乳房炎最重要的病原菌.目前,全世界有三分之一的奶牛患有奶牛乳腺炎,每年因乳腺炎造成的损失高达350亿美元[1].     

Effects of subinhibitory concentrations of florfenicol on morphology, growth, and viability of Staphylococcus aureus

Staphylococcus aureus strain Newman was investigated for changes in its growth pattern, its morphology and its viability when grown in the presence of 3 microg/ml florfenicol (Ff). This concentration corresponds to the 0.75-fold strain-specific minimum inhibitory concentration (MIC). Under these conditions, S. aureus Newman showed a distinct retardation in its growth pattern and 20% dead cells were detected in a fluorescence microscopic viability assay. However, bactericidal activity - defined as a 3-log drop in the staphylococcal population - was not recorded at this Ff concentration. Further analysis of the cell wall revealed a significant increase in cell wall thickness of S. aureus Newman when grown in the presence of 3 microg/ml Ff. This might result in a compression of the protoplast with subsequent disruption of single staphylococcal cells. Accordingly, 20% of the staphylococcal cells analysed by electron microscopy proved to be disrupted. These observations suggest that Ff can cause a thickening of the cell wall accompanied by impaired viability of the staphylococcal cells.     

Secretory virulence factors produced by Staphylococcus aureus isolates obtained from mastitic bovine milk--effect on bovine polymorphonuclear neutrophils

The aim of the research was to test whether exogenic virulence factors secreted by Staphylococcus aureus isolates are involved in mechanisms that allow the bacteria to modulate and evade phagocytosis by bovine polymorphonuclear neutrophils. The research was based on the comparison of the effects of supernatants, prepared from cultures of 30 S. aureus isolates, on the functional properties of bovine neutrophils in vitro. S. aureus isolates were collected from milk samples from cows with clinical mastitis. Supernatants, which were used to treat leukocytes, were prepared from 18 h S. aureus cultures. Exogenic virulence factors secreted by S. aureus isolates significantly influenced the phagocytosis parameters evaluated. Depending on their leukotoxic or superantigenic properties, supernatants could affect the ingestion process, and also showed an influence on the digestion efficiency and phagocytosis carried out by bovine polymorphonuclear neutrophils in vitro.     

金黄色葡萄球菌产肠毒素规律的初步研究

为研究金黄色葡萄球菌产毒的最佳条件和规律。依国标GB/T4789-10-2003液体透析培养法培养质控金黄色葡萄球菌,采用全自动荧光/化学发光分析仪检测金黄色葡萄球菌肠毒素,利用正交试验设计得最佳工艺,应用于质控金黄色葡萄球菌和分离菌。结果显示,质控金黄色葡萄球菌培养40 h,温度为40℃,培养室空气中氧含量为15.5%时肠毒素产量最大,单个菌落肠毒素产量为59.31 mg。表明生产工艺中产毒培养温度和振荡培养时间以及空气中氧含量对肠毒素的产量影响较大。     

Biofilm production by Staphylococcus aureus associated with intramammary infection

Biofilm production by 221 Staphylococcus aureus isolates from 45 dairy herds was evaluated. Isolates were from composite milk of 117 cows, from teat skin of 70 cows, and from 34 milking machine unit liners. Of S. aureus from milk samples, 41.4% were biofilm producers, as compared to 24.7 and 14.7% of the isolates collected from skin and liners. Pulsed field gel electrophoresis (PFGE) best categorized S. aureus biofilm producers as compared to phage typing and binary typing. PFGE types that were significantly associated with isolation from milk as opposed to teat skin or liners, had isolates that were more likely to produce biofilm than PFGE types that were isolated from milk, skin and liners at similar frequencies. By contrast, PFGE type A was significantly associated with isolation from teat skin and had few biofilm producers. PFGE type Q, which is exclusively a milk, isolate produced more biofilm as evidenced by absorbance values. Given S. aureus that are associated with milk are more likely to produce biofilm as compared to extramammary sources (teat skin and milking unit liners), suggests that biofilm production is a risk factor for infection.     

International dissemination of a high virulence rabbit Staphylococcus aureus clone

High virulence rabbit Staphylococcus aureus strains cause chronic and spreading problems of mastitis, pododermatitis and subcutaneous abscesses on rabbit flock level, whereas infections with low virulence strains are limited to individual rabbits. In the present report, 13 high virulence rabbit S. aureus strains, selected out of a large collection of strains isolated in five European countries between 1983 and 2004, were genotyped using pulsed-field gel electrophoresis, spa typing, multilocus sequence typing (MLST) and accessory gene regulator (agr) group typing. Two low virulence rabbit S. aureus strains were also included in the study. The results indicate the clonal origin of high virulence rabbit S. aureus strains present in Europe. Furthermore, the results of MLST and spa typing form a basis for international epidemiology of rabbit S. aureus strains, as these DNA sequence-based typing techniques can easily be used for intercentre comparisons.     

不同佐剂对奶牛乳房炎金黄色葡萄球菌多价毒力因子疫苗免疫效果的影响

为评价佐剂对金黄色葡萄球菌(S.aureus)CP8-FnBPB-ClfA免疫效果的影响,用纯化的S.aureus血清8型荚膜多糖与FnBPB-ClfA蛋白偶联的偶联物配合不同佐剂对健康成年新西兰大耳白母兔进行免疫接种,第1、2、3、4组的佐剂分别为弗氏佐剂、铝盐佐剂、脂质体佐剂及大肠杆菌不耐热肠毒素B(LTB),第5组为对照组用PBS免疫。用间接ELISA法和Western blot对各组兔血清中的抗体进行监测,评价体液免疫效果;通过检测Th1/Th2类细胞因子含量变化评价机体免疫被激活的程度;T淋巴细胞增殖试验评价细胞免疫,并对三免后2周的白兔进行攻毒保护试验。结果显示,以脂质体为佐剂的组7d时开始产生抗体,为产生抗体最早组,14d后抗体水平就开始下降;以LTB为佐剂的组抗体水平最高,持续时间最长。细胞免疫水平检测结果显示,经ConA刺激后,各组T淋巴细胞普遍增殖,无显著差异,刺激指数都在1.0左右;用抗原刺激的组中,以LTB为佐剂的组T淋巴细胞增殖能力最强,刺激指数为2.23,对白兔的攻毒保护率为80%。     

Enhanced virulence of Staphylococcus aureus from bovine mastitis induced by growth in milk whey

The virulence towards mice of Staphylococcus aureus strains from bovine mastitis was enhanced upon growth in milk whey compared to homologous organisms grown in tryptic soy broth (TSB). In the mouse mastitis model, S. aureus grown in milk whey caused more severe lesions than homologous strains grown in TSB. Staphylococcus aureus strain F1440 grown in milk whey induced 75% mortality and local necrotic reaction in subcutaneously inoculated mice, whereas the homologous strain grown in TSB caused only 5% mortality and slight skin reaction. Extracellular capsule on milk whey-grown, S. aureus could not be demonstrated. However, diffuse type colony morphology could be correlated with an increased virulence of S. aureus towards mice.