共查询到19条相似文献，搜索用时 78 毫秒
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细菌天然群体感应信号分子抑制剂研究进展 总被引：1，自引：0，他引：1
长期抗生素滥用导致了多重耐药菌株及其超级细菌的出现,由密度感应系统调控的生物被膜的形成和成熟是造成细菌感染的机制之一。自然界存在的生物活性物质能够淬灭密度感应系统,这些生物活性物质被称为群体感应信号分子抑制剂(quorum sensing inhibitor,QSI)。近年来,群体感应抑制剂成为细菌抗感染药物开发的靶点,有必要对细菌群体感应信号分子抑制剂种类、作用机制进行研究,本文综述了细菌天然群体感应信号分子抑制剂,干扰群体感应系统,从而治疗细菌感染。绝大多数原核生物能够产生群体感应抑制剂,这被认为是安全的。动物、豆类、传统的药用植物、海洋生物均能产生群体感应抑制剂。这些天然抑制剂可能替代传统抗生素,具有广阔的研究和应用前景。 相似文献
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黄芪多糖在鸡病防治中的应用 总被引：18，自引：1，他引：18
黄芪多糖是黄芪的主要活性成分之一。本文综述了黄芪多糖作为免疫增强剂增强鸡机体免疫力、增强细菌类疫苗的保护力和作为抗病毒药物防治病毒性传染病的应用。 相似文献
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盆栽紫花苜蓿（Medicago sativa）接种不同量的（7.5、15.0、22.5 kg·hm-2）的后磷细菌剂,室内培养77 d后收获。结果表明,磷细菌剂22.5 kg·hm-2处理与不施肥相比,接种磷细菌剂能提高苜蓿结瘤量32.40%,牧草干草产量增加45.95%,水溶性碳水化合物、粗蛋白、中性洗涤纤维的含量分别提高0.40%、2.24%和4.88%;与施过磷酸钙750 kg·hm-2处理相比,苜蓿结瘤量、干草产量、水溶性碳水化合物、粗蛋白、中性洗涤纤维分别提高1.60%、12.90%、0.03%、0.02%和0.32%。本研究认为磷细菌剂适宜用量为22.5 kg·hm-2。 相似文献
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细菌多重耐药泵的研究进展 总被引：4，自引：2，他引：2
细菌主要通过药物代谢酶将药物失活、靶向改造药物作用部位、降低细胞膜通透性和通过耐药泵主动将胞内药物泵出胞外4种方式抵抗抗生素和其他药物的毒性作用,其中细菌通过耐药泵将药物排出胞外是细菌的主要耐药机制之一,尤其是多重耐药泵,可以外排结构迥异的多种药物或对细菌有毒的代谢产物。由于细胞膜结构的不同,革兰氏阴性菌和革兰氏阳性菌所具有的耐药泵种类和结构也有所不同。革兰氏阴性菌中,目前发现的细菌耐药泵种类主要包括ATP结合盒超家族(ATP-binding cassette family,ABC)、耐药节结化细胞分化(resistancenodulation division,RND)家族、主要易化子超家族(major facilitator superfamily,MFS)、小多重耐药(small multi-drug resistance,SMR)家族和多药及毒性化合物外排家族(multidrug and toxic-compound extrusion family,MA-TE)。革兰氏阳性菌中,目前发现的细菌耐药泵种类主要包括ABC、MFS、SMR和MATE家族。近年来,诸多学者开展了细菌耐药泵的结构及其耐药机制的... 相似文献
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由于药物管理制度的不健全，抗生素得到了大量的广泛应用和滥用；细菌迫于生存压力不断变异，以适应大量抗生素应用的环境。现在细菌的耐药性愈被人们关注，大量的抗生素疗效愈来愈差，给疾病的有效治疗带来了很大的困难。新的药物增强剂一溶血性磷脂酸(lysophosphatidic acid，LPA)的出现给抗生素世界带来了巨大的生机和活力，不仅使老药重新获得了生命力不再是一个遥远的梦想，而且使用量减少，同时溶血性磷脂酸此项功能的发现也给兽药领域带来了巨大商机，也为人们敲响了警钟，抗生素的滥用和细菌耐药性的严重性迫切要求人们加强人类医药和兽药的管理，健全各类药物的管理制度刻不容缓。 相似文献
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K L Mealey 《Journal of the American Veterinary Medical Association》2001,218(12):1893-1896
beta-Lactamase production by bacteria continues to be one of the main mechanisms of bacterial resistance to beta-lactam antibiotics, and it seems likely to remain so. beta-Lactamase inhibitors provide 1 strategy to overcome this mechanism of bacterial resistance. Although 3 beta-lactamase inhibitor/antibiotic combinations are currently available, only 1 is approved for veterinary use. Because the beta-lactamase inhibitor must be present concurrently with the antibiotic for synergistic activity, it is important to consider the pharmacokinetic profile of these drugs in combination. These combinations were developed and optimized for human patients, so it is unlikely that they would achieve the ideal plasma and tissue concentrations and ratios in veterinary patients. Indeed, several differences in pharmacokinetic variables of beta-lactam antibiotic/beta-lactamase inhibitor agents have been described in dogs, compared with people. Such pharmacokinetic differences should be considered when interpreting in vitro susceptibility results in veterinary species, because these tests use ratios of drug that were established for humans. The beta-lactamase inhibitors represent a successful example of targeted drug development. However, the currently available inhibitors are active primarily against class-A beta-lactamases. Because the frequency with which class-C beta-lactamases are recognized is rapidly increasing in human isolates, and because beta-lactamase enzymes continue to evolve, new beta-lactamase inhibitors will need to be developed to target these enzymes. 相似文献
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A number of researchers have used chemical inhibitors that target membrane efflux pumps as an experimental treatment strategy for multidrug resistant (MDR) bacterial infections. However, most of these compounds are toxic in vertebrate animals. The present research was therefore done to describe expression dynamics of drug resistance-associated Escherichia coli proteins that could serve as novel drug targets. Proteomes of MDR and antimicrobial susceptible (AS) E. coli were studied in two dimensional (2-D) polyacrylamide gels and liquid chromatography-mass spectrometry (LC-MS) was performed on proteins of interest. The number of recovered peptides per protein was used to elucidate the amounts of target proteins expressed in MDR and AS E. coli strains. Eight proteins that may be potentially involved in mechanisms of drug resistance were analyzed and identified by LC-MS. These were grouped into membrane porins (TolC, OmpA, OmpC, Nmpc Precursor), proteins involved in microbial protein synthesis (EF-Ts, EF-Tu, RpsA) and Dps, a protein of unknown location and function. Experimental data demonstrated variability in the expression patterns and quantities of the four porins (TolC, OmpA, OmpC, Nmpc precursor), the three microbial protein synthesis associated proteins (EF-Ts, EF-Tu and RpsA), and Dps which has been previously associated with drug resistance. While variability was seen in quantities and expression patterns of some of the proteins of interest, the present data falls short of determining the suitability of these proteins as novel drug targets. Further studies are required to explore how these proteins could be targeted for drug development. 相似文献
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本试验旨在鉴定临床疑似沙门氏菌感染致死信鸽的病原菌并确定致病菌的耐药及毒力状况。通过细菌分离培养、菌落形态观察、染色镜检、生化鉴定、血清分型、16S rRNA基因测序分析和康复信鸽血清平板凝集试验进行鉴定,并通过药敏试验、耐药基因和毒力基因检测进行耐药性和毒力分析。结果显示,分离纯化的细菌在BS、XLD、HE培养基上为黑色菌落,镜检为无荚膜、无芽孢的革兰氏阴性短杆菌;分离菌株生化反应结果符合沙门氏菌生化特性;分离菌株血清型为1,4,12：i：1,2;分离菌株16S rRNA基因序列系统进化树分析显示,该分离菌株与鼠伤寒沙门氏菌聚为一支,同源性>99%,康复信鸽血清与分离菌株发生特异性凝集,结合生化反应和血清分型结果该菌株鉴定为鼠伤寒沙门氏菌;分离菌株对氟苯尼考耐药,经耐药基因检测携带floR、cmlA氯霉素类耐药基因,与耐药表型相符;分离菌株mogA等17种毒力基因检测均为阳性。本试验成功分离到1株信鸽源鼠伤寒沙门氏菌,分离菌株对氟苯尼考耐药且具有较强毒力,为下一步信鸽沙门氏菌的防治和研究提供了参考依据。 相似文献
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化脓隐秘杆菌(Trueperella pyogenes,T.pyogenes)是一种能够引起动物和人化脓性感染的重要病原菌。随着抗生素的广泛使用,该菌已对临床常用的大环内酯类、四环素类等药物产生不同程度的耐药性。本试验拟探讨外排泵抑制剂利血平对T.pyogenes大环内酯类外排基因mefA mRNA及蛋白表达的影响,将为细菌外排泵抑制剂的研究奠定理论基础。以携带mefA基因的T.pyogenes分离株(17,20号)为试验菌株,采用荧光定量PCR及Western blot技术,检测利血平作用前后各菌株mefA基因mRNA及蛋白表达量。结果表明,1/2 MIC利血平作用2株耐药菌株36 h后,大环内酯类抗生素红霉素、罗红霉素、泰乐菌素、阿奇霉素和替米考星对携带mefA基因的T.pyogenes的MIC值均有不同程度的降低。17和20号分离株外排基因mefA mRNA表达水平较药物作用前均极显著降低(利血平作用前是作用后的5.18,17.54倍),外排蛋白MefA表达量较药物作用前也显著降低(利血平作用前是作用后的1.08,1.70倍),且基因水平和蛋白水平的变化与其耐药表型的变化趋势一致;提示利血平可能是通过抑制外排基因mefA的转录和翻译而消减T.pyogenes对大环内酯类抗生素的耐药性。 相似文献
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抗菌药仍是治疗病原菌引起的奶牛疾病的常用方法。抗菌药的不合理使用使得细菌产生耐药性已成为全球性的问题,应引起人们的足够重视。奶牛的主要病原菌金黄色葡萄球菌、链球菌、大肠杆菌等也显现出多重耐药的趋势,给奶牛疾病的临床治疗带来困难,同时也威胁人类健康。细菌产生耐药性的速度远超过人们研发抗菌药的速度,因此,保持现有抗菌药的疗效很有必要。一方面应该掌握细菌的耐药机制,如细菌分子耐药机制、抗菌药物外排机制或降低摄入机制、生物膜等,以便找到合适的治疗方法;另一方面采用不同措施减少耐药细菌的出现,如质粒消除、抗菌药替代品、开发高效安全的抗菌药物、临床合理用药（联合治疗）等。作者对奶牛主要病原菌的耐药情况、耐药机制、耐药控制技术进行综述,以期为减少耐药性、规范抗菌药的使用和提高治疗效果提供参考。 相似文献