共查询到18条相似文献，搜索用时 671 毫秒
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条件致病菌铜绿假单胞菌（PA）是一种能形成生物膜的革兰氏阴性菌,作者综述了PA生物膜形成的生物学机制,包括菌体黏附、胞外多糖Psl和Pel、藻朊酸盐等参与细菌生物膜成熟的过程及群体感应系统调节相关因子表达,从而调控细菌形成生物膜应对不良环境。此外还概括了将生物膜作为靶点开发的药物等生物膜相关的研究进展。生物膜是菌体逃避有害刺激的护盾,研究其结构、形成及致病机理,了解PA产生耐药性的分子机制,对于通过调节生物膜形成或调控生物膜相关因子的表达进而优化PA的抗感染治疗有十分重要的意义。 相似文献
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在冷藏的原料乳中,假单胞菌经常出现并成为主导菌群,其分泌的耐热酶会使原料乳变质。对从原料乳中分离的102株假单胞菌经rpoB基因测序进行菌种分析,用偶氮酪蛋白测试所有假单胞菌在2种培养条件(30℃培养2d或6℃培养8d)下胞外肽酶的蛋白水解活性和耐热性。结果表明:荧光假单胞菌(Pseudomonas fluorescens)是假单胞菌中最主要的菌种,其次是莓实假单胞菌(Pseudomonas fragi)和假单胞菌sp1 (Pseudomonas sp1)。不同假单胞菌菌种之间的产肽酶能力存在明显差异。大多数荧光假单胞菌(23/41)在不同温度(30℃和6℃)条件下培养后能产肽酶,而大多数的假单胞菌sp1不产肽酶,所有分离的莓实假单胞菌(13/13)只在6℃条件下产肽酶,大多数的假单胞菌所产肽酶都有热稳定性。在6℃培养条件下,荧光假单胞菌菌株M02有最高肽酶活力(11.78ΔA/ (h·mL)),其胞外肽酶最佳催化pH值为6.5,最佳催化温度为40℃。当M02的接种浓度为103 CFU/mL时,6℃培养5d就能使脱脂乳溶液产生沉淀。对耐冷假单胞菌的种类和产肽酶能力进行分析和考察有助于提高原料乳或乳制品的质量和安全性。 相似文献
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为了研究连翘提取物对铜绿假单胞菌群体感应系统的影响,试验采用紫色杆菌CV026初步观察连翘提取物的群体感应抑制作用,并将不同浓度的连翘提取物与铜绿假单胞菌共同培养,通过测定铜绿假单胞菌生长曲线、生物被膜、鼠李糖脂、绿脓素及蹭行运动的变化,进一步研究连翘提取物对铜绿假单胞菌群体感应系统的抑制作用。结果表明:连翘提取物在亚抑菌浓度下能够降低紫色杆菌紫色菌素的分泌;连翘提取物浓度低于250 g/L时,可抑制生物被膜形成、鼠李糖脂及绿脓素的分泌并减弱铜绿假单胞菌蹭行运动能力,并呈浓度依赖性。说明连翘提取物对铜绿假单胞菌的群体感应系统起抑制作用。 相似文献
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荧光假单胞菌防治植物病害研究现状与展望 总被引：4，自引：0，他引：4
随着植物病害的日趋严重,生物防治已经成为国内外学者研究的重点,其中,荧光假单胞菌尤为重要。本研究综述了荧光假单胞菌的培养特征(形态特征、生理生化特性、培养条件和与其他菌的异同);从不同类群的植物分离到防治病害的荧光假单胞菌;荧光假单胞菌的生防效果(单独使用和与其他菌或物质交互使用的防治效果);荧光假单胞菌及活性物质防治植物病害的作用方式和作用机理;荧光假单胞菌在医学、农业和环保领域中的危害。对其风险和在生物防治领域的发展前景做了评价和展望。 相似文献
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假单胞菌通常被认为是危害原料乳及其制品的主要嗜冷菌,其分泌的胞外蛋白酶具有耐热性,甚至能在超高温灭菌处理后仍有活性残留,并减短超高温灭菌乳的货架期.本文对来自牛乳中的嗜冷假单胞菌蛋白酶的研究进展做了总结,重点假单胞菌蛋白酶的催化机制研究进展,相关基因包括蛋白酶基因apr X在假单胞菌鉴别中的应用研究进展.最后讨论了嗜冷假单胞菌蛋白酶需要深入研究的方向. 相似文献
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【目的】 研究甘草查耳酮A对貂源铜绿假单胞菌的抗菌活性，为临床合理使用甘草查耳酮A抗感染治疗提供依据。【方法】 采用微量肉汤稀释法和平板计数法测定甘草查耳酮A对貂源铜绿假单胞菌的最小抑菌浓度（minimal inhibitory concentration，MIC）和最小杀菌浓度（minimum bactericidal concentration，MBC）；平板计数法测定1MIC、2MIC、4MIC和8MIC甘草查耳酮A对铜绿假单胞菌的杀菌效果；吸光光度法测定1/16MIC、1/8MIC、1/4MIC和1/2MIC甘草查耳酮A对铜绿假单胞菌生长的影响；结晶紫染色法测定1/8MIC、1/4MIC、1/2MIC和1MIC的甘草查耳酮A对铜绿假单胞菌生物被膜的抑制效果以及1/4MIC、1/2MIC、1MIC和1MBC甘草查耳酮A对生物被膜的清除效果；建立小鼠皮肤刀伤模型和皮肤脓肿模型评价甘草查耳酮A对铜绿假单胞菌感染小鼠的治疗效果。【结果】 甘草查耳酮A对貂源铜绿假单胞菌临床分离菌株具有良好的抗菌活性，MIC和MBC分别为3.125和12.5 μg/mL。时间-杀菌曲线结果显示，2MIC和1MIC组在6 h内铜绿假单胞菌数量逐渐减少，之后基本维持在1×105 CFU/mL左右；8MIC和4MIC组铜绿假单胞菌的数量一直处于下降趋势，并且分别在14和16 h后均无菌落形成。1/16MIC甘草查耳酮A对铜绿假单胞菌生长影响不明显，而1/8MIC、1/4MIC和1/2MIC甘草查耳酮A可抑制细菌生长。1MIC甘草查耳酮A对铜绿假单胞菌生物被膜形成的抑制率约为70%，1MBC甘草查耳酮A可清除约50%预形成的生物被膜。体内试验结果表明，甘草查耳酮A有助于铜绿假单胞菌感染小鼠刀伤的创口愈合，并减少皮肤脓肿。与对照组相比，甘草查耳酮A和氨苄西林组脓肿中的细菌数量均极显著减少（P<0.01）。【结论】 甘草查耳酮A对貂源铜绿假单胞菌具有良好的体外和体内抗菌活性，可进一步用于临床治疗铜绿假单胞菌感染制剂的研发。 相似文献
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MENG Fei LI Shu-chang YANG Wu-ning LIU Wei YIN Hui-hui WEI Xiao-jie JIANG Yuan-ming ZHAO Wu QIN Zhen-hua SUN Jian-hua 《中国畜牧兽医》2016,43(11):2976-2981
The opportunistic pathogen Pseudomonas aeruginosa is a gram-negative bacteria which can form biofilms.In this review,we summarized the biology mechanism of biofilms in Pseudomonas aeruginosa,including Pseudomonas aeruginosa adhesion,extracellular polysaccharide Psl and Pel,alginate participated in the biofilm maturation,and quorum sensing systems regulated the formation of biofilm in Pseudomonas aeruginosa,and the drug target on biofilm.The bacterial biofilms protected the bacteria from unsuitable environmental conditions.Through researching the structure and the pathogenesis of Pseudomonas aeruginosa,and its resistance molecular mechanisms,we could adjust or regulate the expression of biofilm-associated factors,optimize the anti-infection treatment in Pseudomonas aeruginosa. 相似文献
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金黄色葡萄球菌是引起奶牛细菌性乳腺炎的主要原因，生物被膜的形成是金黄色葡萄球菌在不利环境条件下持久性存在的关键因素。探索同一株菌在生物被膜态与浮游态生长状态下的耐药性与其生长状态的相关性，可为进一步探究金黄色葡萄球菌的耐药性机制奠定基础。本研究培养了金黄色葡萄球菌的生物被膜，使用光学显微镜和扫描电镜观察其形成过程。测定并比较了9种抗菌药物对32株金黄色葡萄球菌在生物被膜态和浮游态的最小抑菌浓度，并对两种状态下的金黄色葡萄球菌进行转录组学测序，筛选出具有显著性差异的细胞信号通路和表达基因，同时对主要差异表达的基因进行RT-qPCR验证。结果发现，在生物被膜形成前期，随着培养时间的延长，显微镜下观察到的生物被膜态菌聚集面积越来越大，结构也越来越紧密，培养至72 h后，生物被膜逐渐开始分散。MIC测定结果显示浮游态菌的抑菌浓度低于生物被膜态菌。转录组结果显示两种状态菌的差异表达基因共1 512个，其中，生物被膜态菌中上调基因760个，下调752个。GO与KEGG富集分析显示，相比于浮游态菌，生物被膜态菌中与代谢相关的通路显著富集，其次为氨基酸的生物合成和ABC转运蛋白通路。与生物被膜形成相关的基因，如编码ABC转运蛋白的基因表达上调，而与代谢途径相关的基因下调。RT-qPCR验证了10个主要差异基因，其表达差异趋势与转录组测序结果一致。这些差异可能对金黄色葡萄球菌生物被膜态的高耐药性和细菌毒力的研究有所帮助。 相似文献
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Melchior MB Vaarkamp H Fink-Gremmels J 《Veterinary journal (London, England : 1997)》2006,171(3):398-407
Mastitis remains one the most important diseases in dairy cattle despite the progress made in improving general udder health in recent years. Epidemiological studies have revealed that following treatment with antimicrobials, bacteriological cure rates vary between 0% and 80% but with no evidence of a significant loss of activity of the major classes of antibiotics licensed for the treatment of bovine mastitis. Recurrent infections are often attributable to biofilm growth of bacteria and this review provides an overview of those mechanisms related to bacterial biofilm growth in mastitis. Biofilm formation is accompanied by significant genetic and subsequent physiological changes in the microorganisms resulting, inter alia, in a loss of sensitivity to virtually all classes of antibiotics. 相似文献
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奶牛乳房炎是造成奶牛养殖业巨大经济损失的疾病,金黄色葡萄球菌是导致奶牛乳房炎感染的主要致病菌之一。以生物被膜的群落形式存在的金黄色葡萄球菌,更易逃避宿主免疫系统、降低药物敏感性,从而导致奶牛乳房炎反复发作,最终形成顽固性乳房炎。研究显示,天然抗生物被膜物质对金黄色葡萄球菌生物被膜的抑制作用明显,可作为新的抗菌药物应用于奶牛乳房炎的防治。对金黄色葡萄球菌生物被膜耐药机制和天然抗金黄色葡萄球菌生物被膜物质的最新研究进展进行了概述,以期对防治金黄色葡萄球菌导致的奶牛乳房炎提供参考。 相似文献
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Westgate SJ Percival SL Knottenbelt DC Clegg PD Cochrane CA 《Veterinary microbiology》2011,150(1-2):152-159
Horse wounds have a high risk of becoming infected due to their environment. Infected wounds harbour diverse populations of microorganisms, however in some cases these microorganisms can be difficult to identify and fail to respond to antibiotic treatment, resulting in chronic non-healing wounds. In human wounds this has been attributed to the ability of bacteria to survive in a biofilm phenotypic state. Biofilms are known to delay wound healing, principally due to their recalcitrance towards antimicrobial therapies and components of the innate immune response. This study describes the presence of bacterial biofilms within equine wounds. Thirteen 8-mm diameter tissue samples were collected from (n=18) chronic wounds. Following histological staining, samples were observed for evidence of biofilms. Fifty one wounds and control skin sites were sampled using sterile swabs. Control skin sites were on the uninjured side of the horse at the same anatomical location as the wound. The isolated bacteria were cultured aerobically and anaerobically. The biofilm forming potential of all the isolated bacteria was determined using a standard crystal violet microtitre plate assay. Stained tissue samples provided evidence of biofilms within 61.5% (8 out of 13) equine wounds. In total 340 bacterial isolates were identified from all the equine wound and skin samples. Pseudomonas aeruginosa and Enterococcus faecium were the most predominantly isolated bacterial species from equine wound and skin samples respectively. Staphylococcus was the most commonly isolated genus in both environments. Bacteria cultured from chronic and acute wounds showed significantly (P<0.05) higher biofilm forming potential than bacteria isolated from skin. This paper highlights preliminary evidence supporting the presence of biofilms and a high microbial diversity in equine chronic wounds. The presence of biofilms in equine wounds partly explains the reluctance of many lower limb wounds to heal. Non-healing limb wounds in horses are a well documented welfare and economic concern. This knowledge can be used to shape future treatments in order to increase the healing rate and decrease the costs and suffering associate with equine wounds. 相似文献
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Detection of biofilm formation and nanobacteria under long-term cell culture conditions in serum samples of cattle,goats, cats,and dogs 总被引：7，自引：0，他引：7
Barr SC Linke RA Janssen D Guard CL Smith MC Daugherty CS Scarlett JM 《American journal of veterinary research》2003,64(2):176-182
OBJECTIVE: To determine the prevalence of biofilm formation under long-term cell culture conditions in serum samples of dairy cattle, goats, cats, and dogs, and to determine whether there is an association between nanobacteria and biofilm formation. SAMPLE POPULATION: Serum samples of clinically normal animals (313 dairy cattle, 48 goats, 140 dogs, and 44 cats) and animals with various medical conditions (60 dogs and 116 cats). PROCEDURE: Serum was incubated under cell culture conditions and observed for biofilm formation by use of light microscopy, electron microscopy, and spectroscopy. A polymerase chain reaction assay was developed to identify 16S rRNA gene sequences of nanobacteria. RESULTS: Biofilm formation developed in serum samples of 304 of 313 (97%) cattle, 44 of 48 (92%) goats, 44 of 44 (100%) cats, and 126 of 140 (90%) dogs. Prevalence of serum samples with positive results for biofilm formation was not significantly different between cats or dogs with and without medical conditions associated with pathologic extraskeletal calcification processes. Scanning electron microscopy and spectroscopy of biofilm samples revealed small coccoid particles consisting mainly of calcium and phosphate. Polymerase chain reaction assay failed to amplify sequences of nanobacteria. CONCLUSIONS AND CLINICAL RELEVANCE: Under long-term cell culture conditions, biofilm made up of aggregates of calcium and phosphate crystals does form in serum samples of clinically normal dairy cattle, goats, cats, and dogs. Disease, however, does not predispose to biofilm formation in serum samples of dogs and cats. Our findings did not support the existence of nanobacteria in serum samples of cattle, goats, cats, and dogs. 相似文献
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陈伟 《中国兽医寄生虫病》2010,18(4):81-86
链球菌是一群种类多样的革兰氏阳性细菌,定殖在人的表皮、粘膜及牙齿表面。许多链球菌由感受态刺激肽（competence-stimulating peptide,CSP）介导的群感效应（quorum sensing,QS）与形成遗传转化的感受态有关。近期研究表明许多细菌的CSP与细胞密度适应性反应（如感受态与生物膜的形成）直接相关。本文综述了由群感效应介导生物膜形成的链球菌,充分阐明CSP功能,从感受态的形成到其它与细胞密度有关的表型,包括对生物膜形成的影响,以便对CSP的作用有新的理解,为研发新型抗生物膜感染药物、提出有效的生物膜感染防制策略提供理论基础。 相似文献