秦皮素抑菌活性及其机制研究

目的以金黄色葡萄球菌为供试菌株来研究秦皮素对其的抑制活性及其机制。方法利用牛津杯法、2,3,5-氯化三苯基四氮唑(TTC)染色、生长曲线的测定、细胞膜渗透性测定、SDS-PAGE蛋白谱变化方法等对秦皮素的抑菌活性及其机制进行研究。结果秦皮素能够影响金黄色葡萄球菌细胞膜的通透性,秦皮素作用20 h,菌体可溶性蛋白总量减少55.74%。结论秦皮素对金黄色葡萄球菌具有明显的抑制作用,其抑菌机制可能是通过抑制蛋白质的合成来实现的。     

用3种药敏方法评价流感嗜血杆菌对3种β-内酰胺类药物的药敏实验一致性的研究

目的 对比研究3种体外药敏试验在测定流感嗜血杆菌(Haemophilus influenzae,Hi)对氨苄西林、阿莫西林克拉维酸、头孢呋辛等3种β-内酰胺类药物敏感的可靠性及实用性.方法 采用肉汤稀释法、纸片扩散法(K-B法)和自动化微量肉汤稀释法(ATB法)检测Hi对氨苄西林、阿莫西林克拉维酸、头孢呋辛的药物敏感性.以肉汤稀释法为参考方法,分析比较K-B法和ATB法结果间的一致性和误差率.结果 K-B法与肉汤稀释法对氨苄西林、阿莫西林克拉维酸、头孢呋辛的药敏一致率分别为77.19％、91.58％、69.16％,ATB法与肉汤稀释法的一致率分别为70.18％、73.16％、51.98％,K-B法对阿莫西林克拉维酸、头孢呋辛这两种药物的一致率显著高于ATB法.结果 误差方面,K-B法对氨苄西林和头孢呋辛的重大误差率和极重大误差率都显著低于ATB法,K-B法对阿莫西林克拉维酸的重大误差率也显著低于ATB法.结论 检测Hi对β-内酰胺抗生素药敏实验方面,K-B法和肉汤稀释法的一致性较好;ATB法对Hi药敏试验产生的误差较大.临床工作中报告ATB法药敏结果时,应结合β-内酰胺酶试验,出现异常药敏表型,或者对ATB药敏结果有疑问时,建议联合使用其他药敏方法,对ATB法结果进行修正.     

黄粉虫抗菌肽Tenecin蛋白的纯化及其抑菌活性研究

目的 纯化黄粉虫抗菌肽Tenecin蛋白,并检测其抑菌活性.方法用1 mmol/L IPTG大量诱导表达Tenecin蛋白,纯化后检测其抑菌活性,包括金黄色葡萄球菌(Staphylococcus aureus)ATCC 29213,大肠埃希菌(Escherichia coli)ATCC 25922,白色念珠菌(Candida albicans)ATCC 10231和痢疾志贺氏菌(Shigella dysenteriae)CMCC 51252等4种标准菌.结果 SDS-PAGE电泳检测表明已获得纯化的Tenecin蛋白;体外抑菌试验结果表明,浓度为120、60、30、15 μg/ml的Tenecin与4种标准菌共培养18 h后,对金黄色葡萄球菌的抑制作用最强,而对白色念珠菌的抑制作用最弱.对同一菌种而言,浓度为60和30 μg/ml两组间无统计学意义(P＞0.05),而其他各浓度的组间均有显著性差异(P＜0.01);对同一浓度的Tenecin而言,其对白色念珠菌和痢疾志贺氏菌的抑菌效果组间无统计学意义(P＞0.05),其余各组之间均有显著性差异(P＜0.01).结论 获得的Tenecin蛋白可明显抑制病原菌,为进一步研究其抑菌机理和后期研发奠定了基础.     

微热法对新化合物抑菌活性的研究

本文设计合成了 N~4-甲基-1,3,4-噻二唑苯甲醛缩氨基硫脲及其 Co(Ⅱ)的配合物,经红外光谱证实其结构,同时用微热检测系统对其抑菌活性进行了研究,计算了在不同抑菌浓度下的细菌生长速度,求得了抑菌剂的最适应用浓度。     

中药制剂对多重耐药细菌的体外抑菌试验

目的了解肺炎一号对MRSA(耐甲氧西林的金黄色葡萄球菌)、ES-BLs+(产超广谱β-内酰胺酶)的肺炎克雷伯菌抑菌效果。方法采用血清药理学方法,梯度稀释含药血清,进行体外抑菌试验。结果肺炎一号对MRSA、ESBLs+的肺炎克雷伯菌的抑菌效果与阴性对照组比较,差异有极显著性(P<0.01),抑菌效果明显。结论中药制剂在目前棘手的多重耐药的细菌MRSA、ESBLs+的肺炎克雷伯菌抑菌效果明显。     

用PCR分析高水平耐四环素淋病奈瑟菌质粒类型

1985年美国首次分离出高水平质粒介导的耐四环素淋病奈瑟菌（hight-level plasmid mediated tetracycline-resistant N．gonorrhoea，TRNG）以来，在世界各地引起广泛流行，欧洲、非洲、亚洲、拉丁美洲等地区都有报道，有些地方TRNG在质粒介导型耐药菌株中分离率居首位。根据限制性内切酶谱将TRNG分为“荷兰型”和“美国型”两种，“美国型”与1600bp的扩增产物相关，“荷兰型”与700bp大小的扩增产物相关。1991年成都地区首次分离出TRNG，现已成为本地区流行的主要耐药菌株。我国过去对TRNG分型主要采用琼脂稀释法测定对四环素的最小抑菌浓度或质粒抽提等方法，     

骨髓炎治疗用缓释制剂的制备及体外抑菌活性研究

骨髓炎的定点缓释给药治疗是重要的生物医学问题,关键是要制备高效的缓释药棒。我们采用热熔法,以聚(二聚酸(十四烷二酸)共聚物[P(DA-TA),WDA:WTA=50:50]为药物缓释材料,硫酸庆大霉素为模型药物,制备了硫酸庆大霉素-聚酸酐缓释药棒,以期最终用于骨髓炎的定点缓释给药治疗。初步的制剂稳定性研究表明,在室温干燥条件下,该缓释药棒具有良好的制剂稳定性。体外释药结果表明,37℃时,该缓释药棒在蒸馏水中、0．9％生理盐水中和0．1 mol／L pH7．4 PBS中具有明显缓释作用,其体外释药动力学均符合一级动力学方程和Peppas方程。抑菌活性实验表明,该缓释药棒对骨髓炎常见致病菌:金黄色葡萄球菌及大肠杆菌有长达60 d的抑制作用。该类硫酸庆大霉素-聚酸酐缓释药棒具有良好的制剂稳定性和长达60 d的抑菌活性,可望用于骨髓炎治疗领域。     

蒙药材瑞香狼毒炮制前后的体外抑菌活性研究

瑞香狼毒（Stellera chamaejasme L．）又名断肠草、山萝卜、红狼毒等,蒙药名为达楞图如,为瑞香科狼毒属植物。瑞香狼毒性味苦平,有大毒,有逐水祛痰、破积杀虫之功效,临床上主要用于治疗乳腺炎、腮腺炎、脉痈、痘疹、疫热、炭疽、结喉等症,对于植物病原菌也有抑制作用。本文选用金黄色葡萄球菌、铜绿假单胞菌为供试菌种,采用管碟法对瑞香狼毒不同溶剂提取组分及单体化合物的体外抑菌活性进行了研究。     

甲氧西林耐药的金黄色葡萄球菌耐药性及分子流行病学调查

目的了解甲氧西林耐药的金黄色葡萄球菌(MRSA)的耐药性及分子流行病学特点。方法采用纸片扩散法及琼脂稀释法检测2002年从北京协和医院住院患者分离的165株MRSA的耐药性；采用脉冲场凝胶电泳(PFGE)技术对其中重症监护病房(ICU)和呼吸重症监护病房(RCU)分离的65株MRSA作同源性分析。结果165株MRSA对万古霉素和替考拉宁的敏感率为100％，对庆大霉素的耐药率为100％；对左氧氟沙星、四环素、红霉素耐药率分别为98．2％、96．3％、93．9％。对甲氧苄啶，磺胺甲噁唑和氯霉素敏感率分别为95．8％及98．8％；ICU和RCU病房分离MRSA的PFGE图谱有5种类型(A—E型)，以A型为主(56株)，A型又包括A1亚型(55株)和A2亚型(1株)。结论医院获得性MRSA是多重耐药菌，在ICU和RCU病房发生了基因型为A1亚型的MRSA菌株暴发流行。     

吉西他滨对胰腺癌细胞PANC-1活性和蛋白表达的影响

目的：研究吉西他滨（健择,Gemcitabine,GEM）对胰腺癌细胞PANC-1活性及蛋白表达的影响。方法：应用噻唑蓝（MTT）比色法检测吉西他滨在不同时间（12h、24h、36h、48h）下对胰腺癌细胞PANC-1存活率的影响,透射电镜观察吉西他滨对胰腺癌细胞PANC-1形态的影响,蛋白印迹法观察经吉西他滨作用前后蛋白的表达。结果：吉西他滨对PANC-1细胞生长的抑制有时间依赖性,透射电镜观察胰腺癌细胞发生核质疏松,核膜分层、起泡甚至破裂,核质溢出,胞浆也出现空泡,细胞膜和细胞器发生明显改变,随而质膜渗透性增加并细胞溶解,蛋白印迹法显示,GEM影响蛋白质表达。结论：吉西他滨对胰腺癌细胞PANC-1的生长具有显著抑制作用。药物敏感性降低和作用时间延长能导致蛋白的表达及改变。     

In vitro antibacterial activity of sucralfate

The effect of sucralfate (12.5 mg/ml) on the growth ofEscherichia coli (ATCC 25922),Enterococcus faecalis (ATCC 29212) and two isolates ofPseudomonas aeruginosa (ATCC 27853 and a multi-resistant clinical isolate) was studied in vitro at pH values of 3.0, 4.5, 6.0 and 7.4. A bacteriostatic effect of sucralfate was demonstrated forPseudomonas aeruginosa at a pH of 6.0 and 7.4 and forEscherichia coli andEnterococcus faecalis at a pH of 6.0. The bacteriostatic effect was most pronounced at high pH values. Sucralfate had no bactericidal effect on the bacteria tested at the concentration used.     

壳聚糖抑菌性能的研究进展

壳聚糖是一种天然碱性多糖,因其良好的生物相容性、抗微生物性、可降解性而被广泛应用于食品工程、医药行业、工业降解等领域。而对壳聚糖抑菌性的相关研究一直以来是其特性研究中的热点。本文回顾了从2000年至2018年国内外对壳聚糖抑菌性的研究情况,对其抑菌性影响因素及抑菌机制做了总结,提出了在抑菌性研究方面的问题和观点。以期为壳聚糖抑菌性进一步研究及应用提供理论基础和科学依据。     

国产甲磺酸培氟沙星体内抗菌活性试验

口服和静脉给予国产甲磺酸培氟沙星对大肠杆菌-12、克氏肺炎杆菌-64和绿脓杆菌-14感染小鼠均有保护作用,其中口服给药的PD_(50)分别为1.08,5.87和8.10mg/kg;静脉给药的PD_(50)分别为0.54,3.10和7.02mg/kg。     

The antibacterial activity of Magainin I immobilized onto mixed thiols Self-Assembled Monolayers

An antibacterial peptide, Magainin I, was covalently bound to a mixed 11-mercaptoundecanoïc acid (MUA) and 6-mercaptohexanol (C6OH) (ratio 1:3) Self-Assembled Monolayer (SAM) on gold surfaces. Each step of the surface functionalization was characterized by Polarization Modulation Reflection Absorption InfraRed Spectroscopy (PM-RAIRS) and X-ray Photoelectron Spectroscopy (XPS). The antibacterial activity of the anchored Magainin was tested against three Gram-positive bacteria (Listeria ivanovii, Enterococcus faecalis and Staphylococcus aureus), and the results revealed that the adsorbed Magainin I reduced by more than 50% the adhesion of bacteria at the surface, together with the killing of the bacteria that nonetheless adhered to the surface. No release of the peptide was observed upon contact with the bacterial suspension; the activity has proven to be persistent overtime, up to six months after the first use.     

The inhibition of neutrophil antibacterial activity by ultra-high molecular weight polyethylene particles

Following infection, bacterial killing by polymorphonuclear leukocytes (neutrophils) is the main host defense against bacteria. Our hypothesis is that particles of ultra-high molecular weight polyethylene (UHMWP) may impair local neutrophil function and consequently reduce neutrophil bacterial killing. To determine how the in vitro phagocytic-bactericidal activity of neutrophils was affected by exposure to wear particles, tests were run comparing the effects of different particle composition, and different concentrations and sizes of UHMWP particles. There was a significant correlation between the number of particles and the decrease in neutrophil bactericidal activity (p<0.01), and the greatest effect was obtained with a concentration of 10(7) UHMWP/ml. There was a significant decrease in neutrophil bactericidal activity by incubation with particles of 0.1-5 microm (p<0.01), but not with larger size. The results suggest that neutrophil functional defects triggered by the presence of UHMWP particles may potentially contribute to the susceptibility of loose implants to bacterial infections.     

The effect of systematic structural modifications on the antibacterial activity of novel oxazolidinones

A novel series of tetraethylene glycol (TEG) triazolyl and squaramide containing oxazolidinones were synthesized and tested for their antibacterial activity against a selected panel of Gram-positive and Gram-negative bacteria. The 4-TEG-triazolyl derivatives were prepared by 'click reaction'. The introduction of the TEG and squaramide groups did not favor antibacterial activity. The three nucleoside-containing oxazolidinones were also prepared by 'click' methodology resulted in weak antibacterial activity.     

Bactericidal activity and cytotoxicity of antibacterial monomer MDPB

The aim of this study was to investigate bactericidal characteristics and cytotoxicity of the newly developed antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB). To evaluate the bactericidal activity of MDPB against oral streptococci, the minimum bactericidal concentration (MBC) for seven species and time-kill kinetics against Streptococcus mutans were determined. The cytotoxic effects of MDPB on human pulpal cells were assessed by [3H]-thymidine uptake after contact with MDPB solutions at various concentrations. MDPB showed strong bactericidal activity against seven streptococci, the MBC value ranging from 31.1 to 62.5 micrograms ml-1. Time-kill determination indicated a rapid killing effect of MDPB at 250 micrograms ml-1 or over, and all cells were killed within 1 min by MDPB at 500 micrograms ml-1 or over. No cytotoxic effect was observed on contact with MDPB at concentrations of 10 micrograms ml-1 or less, and the toxicity of MDPB was considered to be similar to those of other monomers used for dental materials. These results suggest that MDPB can be effectively incorporated in dental resin-based materials to provide bactericidal activity against oral bacteria.