纳米银对金黄色葡萄球菌的抗菌作用及其机制研究

目的以金黄色葡萄球菌为对象,研究纳米银的抗菌作用,并对抗菌机制进行探讨。方法金黄色葡萄球菌(ATCC6538)、双倍浓度营养肉汤和营养肉汤由中国食品药品检定研究院提供;纳米银粉末(≤100 nm,576832-5G,SIGMA-ALORICH)。采用最小抑菌浓度(MIC)实验,测定纳米银对金黄色葡萄球菌的振荡培养时(转速为300 r/min)最小抑菌浓度值;采取烧瓶振荡法测定质量浓度50.00、100.00、200.00、800.00μg/m L纳米银对金黄色葡萄球菌作用的光密度(OD)值;扫描电子显微镜观察纳米银处理后金黄色葡萄球菌结构的变化。结果振荡培养时,纳米银对金黄色葡萄球菌的MIC值为800.00μg/m L;纳米银使金黄色葡萄球菌的延滞期延长,浓度800.00μg/m L纳米银溶液能够完全抑制金黄色葡萄球菌在肉汤培养液中的增殖生长;用50.00μg/m L的纳米银作用金黄色葡萄球菌4 h,电子显微镜结果显示,金黄色葡萄球菌细胞壁破裂、胞内物质外流及细胞的死亡。结论纳米银对金黄色葡萄球菌有抗菌作用,可能进入细菌细胞内造成其死亡。     

针刺诱导家蝇幼虫抗菌物质的动态观察

目的观察家蝇幼虫经针刺损伤并感染金黄色葡萄球菌后,家蝇幼虫抗菌物质的动态表达效果。方法室内饲养的家蝇3龄幼虫,经针刺损伤感染金黄色葡萄球菌后,分别于第0、12、24、36、48、60小时记录幼虫存活率,并提取其血淋巴,以溶壁微球菌和金黄色葡萄球菌作指示菌,采用平板法做抑菌试验,37℃恒温24 h观察抑菌圈,并以抑菌圈直径表示抗菌活力的大小,取诱导后高峰时间产生的抗菌物质进行抑菌实验,探讨家蝇抗菌物质诱导产生的规律。结果针刺损伤感染金黄色葡萄球菌后,家蝇幼虫存活率逐渐降低,提取的血淋巴对溶壁微球菌和金黄色葡萄球菌的抑菌活力峰均出现在诱导后48 h。结论针刺损伤感染金黄色葡萄球菌处理法可诱导家蝇产生抗菌物质,在诱导后48 h收集血淋巴最为适宜。     

链霉菌CPCC 203577产生的napyradiomycins的分离与鉴定

目的对一株具有抗菌活性的链霉菌CPCC 203577产生的次级代谢产物进行系统研究。方法采用ISP2琼脂平板发酵培养链霉菌CPCC 203577,乙酸乙酯提取发酵培养物,获得粗提物;粗提物经反相色谱柱、凝胶色谱柱、制备型TLC和半制备HPLC等分离纯化获得目标化合物纯品;MS和NMR等确定化合物结构;琼脂稀释法测定抗菌活性。结果从链霉菌CPCC 203577中分离鉴定了含萘醌并吡喃母核的3个已知化合物,3-chloro-6,8-dihydroxy-8-α-lapachone(1)、16-dechloro-16-hydroxynapyradiomycin C2(2)和napyradiomycin A2(3)。化合物1具有较强的抗革兰氏阳性细菌活性,最低抑菌浓度(MIC)值为4~8μg/ml;化合物2和3没有抗菌活性。结论链霉菌CPCC 203577具有丰富的次级代谢产物合成能力,产生napyradiomycins类化合物。     

头孢哌酮/舒巴坦体外抗菌活性的研究

采用琼脂平板稀释法测定了头孢派酮/舒巴坦(SPZ,比例1:1)、头孢哌酮(CPZ)和舒巴坦(SBT)对8种322株临床常见致病菌的最低抑菌浓度(MIC),并统计了MIC50、MIC90、IC50等数值。结果表明,除金黄色葡萄球菌外,SPZ对其它7种致病菌的抗菌活性均强于CPZ,MIC90值均下降2—4倍;SPZ对肺炎链球菌、流感嗜血杆菌的MIC50值     

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。     

2013-2015年金黄色葡萄球菌的临床分布及耐药性分析

目的：分析徐州医科大学附属医院2013—2015年金黄色葡萄球菌的临床分布及耐药情况,为临床用药提供依据。方法：收集2013年1月1日至2015年12月31日各类标本检出的金黄色葡萄球菌,临床分离株药敏实验采用标准纸片扩散(K-B)法,结果采用WHONET5.6进行分析。结果：2013—2015年共检出金黄色葡萄球菌1725株,主要来源于痰液(35.4%),在ICU(43.7%)和神经外科(12.6%)检出率最高。2013—2015年,耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus, MRSA)检出率分别为63.3%,59.8%,57.6%。MRSA耐药率大于50.0%的抗菌药物有庆大霉素(53.2%~73.1%)、妥布霉素(62.8%~64.9%)、环丙沙星(67.2%~75.3%)、红霉素(86.6%~92.9%)、四环素(53.5%~65.0%);甲氧西林敏感金黄色葡萄球菌(methicillin-sensitive Staphylococcus aureus,MSSA)对抗生素的耐药率排在前3位的为青霉素(85.4%~93.3%)、红霉素(68.7%~72.4%)、复方新诺明(46.3%~57.9%)。结论：本院分离的金黄色葡萄球菌主要分布在ICU和神经外科,MRSA的耐药率普遍较高,临床医生应根据耐药性合理选用抗菌药物。     

青霉源抗菌肽类霉肽素的体外抑菌活性研究

目的 研究抗菌肽类霉肽素(AF)的体外抑菌活性.方法 通过抑菌圈法和二倍稀释法检测AF的抗菌谱和对金黄色葡萄球菌的MIC;通过检测在AF中传代菌的敏感性确定细菌是否容易对AF产生抗药菌;将AF和细菌在不同温度和pH环境作用后检测抑菌活性,明确AF发挥活性的最适温度和pH值.结果 AF对大部分供试细菌和抗药菌有效,对金黄色葡萄球菌的MIC为0.8 mg/ml,金黄色葡萄球菌在AF中传代200代后敏感性不变.在14℃到30℃之间AF的抑菌活性随温度升高而降低,在pH 3到pH 10之间AF的活性随pH值升高而降低.结论 AF是一种对抗性菌有效的广谱抗菌肽,而且不容易诱导细菌产生抗药性.     

新型纳米银/聚氨酯胆道支架表面抗菌涂层的体外抑菌试验

背景：胆管支架已广泛应用于胆管各种良恶性狭窄的姑息治疗,临床短期疗效显著,但长期疗效由于支架再狭窄而受到限制。 目的：研制新型纳米银/聚氨酯胆管内支架复合抗菌涂层并检测其体外抗菌性能。 方法：原位还原法用纳米银、聚氨酯制备纳米银/聚氨酯抗菌材料,采用抑菌环试验法分别测定实验组(纳米银/聚氨酯)、阳性对照(硝酸银纸片)和阴性对照(普通聚氨酯材料)3组对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌、肺炎克雷伯杆菌和肠球菌的抑菌环直径并记录分析数据。 结果与结论：纳米银/聚氨酯在体外对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌、肺炎克雷伯杆菌和肠球菌均有抑制效果,与硝酸银纸片相比,抑菌效果差异无显著性意义。结果显示纳米银/聚氨酯复合物具有良好的抗菌效果,且具有较好的稳定性。     

青霉源抗菌肽类霉肽素的体外抑菌活性研究

目的研究抗菌肽类霉肽素（AF）的体外抑菌活性。方法通过抑菌圈法和二倍稀释法检测AF的抗菌谱和对金黄色葡萄球菌的MIC;通过检测在AF中传代菌的敏感性确定细菌是否容易对AF产生抗药菌;将AF和细菌在不同温度和pH环境作用后检测抑菌活性,明确AF发挥活性的最适温度和pH值。结果AF对大部分供试细菌和抗药菌有效,对金黄色葡萄球菌的MIC为0．8mg／ml,金黄色葡萄球菌在AF中传代200代后敏感性不变。在14℃到30℃之间AF的抑菌活性随温度升高而降低,在pH3到pH10之间AF的活性随pH值升高而降低。结论AF是一种对抗性菌有效的广谱抗菌肽,而且不容易诱导细菌产生抗药性。     

补骨脂素抗菌双相陶瓷骨的制备及性能检测

背景：近年来中药在骨组织工程中应用的研究在国内处于起步阶段,尚未见到补骨脂素在骨组织工程支架材料中应用的研究报道。 目的：通过真空复合方法制备出补骨脂素抗菌双相陶瓷骨,检测材料的理化性能、抗菌性和细胞相容性。 方法：将猪椎骨经复合焦磷酸钠两次低温煅烧制备双相陶瓷骨,将双相陶瓷骨置于壳聚糖/补骨脂素复合溶液中,制备补骨脂素抗菌双相陶瓷骨。扫描电镜观察补骨脂素抗菌双相陶瓷骨的表面形貌,并检测其抗压强度;采用微生物法检测补骨脂素抗菌双相陶瓷骨对大肠杆菌、金黄色葡萄球菌的抑制效果;将补骨脂素抗菌双相陶瓷骨与小鼠成骨细胞MC3T3-El共培养4,8 d,扫描电镜观察细胞在材料表面的附着与增殖。 结果与结论：补骨脂素抗菌双相陶瓷骨具有天然的孔隙结构,骨小梁、小梁间隙和骨内管腔系统同时存在,抗压强度为(4.69±0.50) MPa,其对大肠杆菌、金黄色葡萄球菌均有较强的抑制作用,抑菌效果明显;小鼠成骨细胞MC3T3-El可在补骨脂素抗菌双相陶瓷骨上很好的附着,保持良好的状态和功能并快速增殖,说明补骨脂素抗菌双相陶瓷骨具有良好的细胞相容性。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

Antibacterial Activity of Tabernaemontana Stapfiana Britten (Apocynaceae) Extracts

Antibacterial and phytochemical screening of methanolic, sequential extracts (hexane, dichloromethane, ethyl acetate and methanol) and alkaloid rich fractions of Tabernaemontana stapfiana Britten was carried out. The phytochemical screening showed the presence of alkaloids, flavonoids, coumarins, tannins and saponins that have been associated with antimicrobial activity. The stem and root bark methanolic extracts showed good activity against the bacterial strains used including the multiple drug resistant Staphylococcus aureus strain with minimum inhibitory concentrations ranging from 15.6 to 500 µg/ml and minimum bactericidal concentrations ranging from 31.25 to 500 µg/ml. The sequential extracts of the root and stem bark had high antimicrobial activity with minimum inhibitory concentrations (MICs) ranging between 3.9 and 250 µg/ml and minimum bactericidal concentrations (MBCs) ranging between 7.8 and 500 µg/ml against the tested microorganisms. The dichloromethane extract of the alkaloid rich fractions however exhibited reduced antibacterial activities as compared to methanol and sequential extracts but the dichloromethane:methanol (4:1) mixture showed high activity with MICs ranging between 15.6 and 250 µg/ml. These antibacterial efficacy studies suggest that Tabernaemontana stapfiana Britten could be a source of antibacterial agents.     

牛磺酸铜干预感染愈合创面血管内皮生长因子A的表达

背景：铜具有广谱杀菌及耐药性强的特点,而且铜作为人体必需微量元素在创面愈合过程中发挥着重要作用。作者前期的实验得到了利于生物体吸收的牛磺酸铜有机化合物。 目的：检测牛磺酸铜的抗菌活性及其对感染创面愈合过程中血管内皮生长因子A表达的影响。 方法：①通过MTT比色法检测牛磺酸铜对金黄色葡萄球菌的最低抑菌浓度。②72只SD大鼠随机分为牛磺酸铜组与生理盐水组两组,于每只大鼠背部制作1个直径1.5 cm的圆形金黄色葡萄球菌感染创面。牛磺酸铜组创面应用最低抑菌浓度的牛磺酸铜溶液1 mL,生理盐水组创面应用生理盐水1 mL,隔日用药1次,直到创面完全愈合。 结果与结论：①经测定牛磺酸铜对金黄色葡萄球菌的最低抗菌浓度为4 g/L。②用药后第7,10天,牛磺酸铜组创面愈合率明显高于生理盐水组(P < 0.05);至第21天,两组创面都完全愈合。③组织学观察显示：用药后第7天,牛磺酸铜组肉芽组织更成熟;用药后第14天,牛磺酸铜组胶原纤维排列整齐,瘢痕窄,胶原内可见再生的毛囊和皮脂腺。④免疫组织化学检测创面血管内皮生长因子A的表达变化显示：牛磺酸铜组血管内皮生长因子A在用药后第3天表达明显高于生理盐水组(P < 0.01),第7,10天,牛磺酸铜组血管内皮生长因子A表达量下降,但仍高于生理盐水组(P < 0.05)。其余时间点表达未见明显差异(P > 0.05)。证实感染创面外用牛磺酸铜药液可以发挥有效的杀菌作用,提高创面愈合率,促进大鼠感染创面血管内皮生长因子A的表达,从而提高创面的愈合质量。     

载米诺环素纳米羟基磷灰石/壳聚糖复合体的体外释放及抑菌性

BACKGROUND: Hydroxyapatite/chitosan (HA/CS) complex may act as a drug carrier for drug release, but little is reported about the release amount and antibacterial effect of minocycline-HA/CS (Mino-HA/CS) complex. OBJECTIVE: To investigate the in vitro release and antibacterial property of Mino-HA/CS complex. METHODS: HA/CS and Mino-HA/CS were prepared using co-precipitation method. The surface and cross-section features of the complexes were observed under scanning electron microscopy. The porosities were measured according to Archimedes Principle. The release of minocycline hydrochloride was measured by high performance liquid chromatography with the simulated saliva as drug release media. In vitro antibacterial effect on Porphyromonas gingivalis and Staphylococcus aureus were measured by bacteria-inhibiting ring method. Biological toxicities were evaluated via cell counting kit-8cell proliferation assay. RESULTS AND CONCLUSION: The porosity of Mino-HA/CS was larger than that of HA/CS, with the average porosity of 53.99%. Single-day release amount of Mino-HA/CS could maintain at the level of 0.5-1 μg per day for a long-term. Bacteriostatic rings of Porphyromonas gingivalis and Staphylococcus aureus still existed clearly after 7 days. Cell proliferation assays showed that Mino-HA/CS extract had the significant effect on promoting cell proliferation. These findings indicate that the Mino-HA/CS sustains the release of minocycline at a relatively stable level within a longer period, shows good inhibitory effect on Porphyromonas gingivalis and Staphylococcus aureus and promotes the proliferation of periodontal ligament cells.     

In vitro antibacterial activity of bovine dialyzable leukocyte extract

The rapidly developing resistance of many infectious pathogenic organisms to modern drugs has spurred scientists to search for new sources of antibacterial compounds. One potential candidate, bDLE (dialysis at 10 to 12 kDa cut-off) and its fractions ("S" and "L" by 3.5 kDa cut-off and I, II, III, and IV by molecular exclusion chromatography), was evaluated for antibacterial activity against pathogenic bacterial strains (Staphylococcus aureus, Streptococcus pyogenes, Lysteria monocytogenes, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi) using standard antimicrobial assays. A minimum inhibitory concentration (MIC) of bDLE and its fractions was determined by agar and broth dilutions methods. Only bDLE and its "S" fraction had an effect upon all bacteria evaluated (MIC ranging from 0.29 to 0.62 U/ml), and the bactericidal and bacteriostatic effects (evaluated by MTT assay) were bacterial species-dependent. These results showed a remarkable in vitro antibacterial property of bDLE against several pathogenic bacteria.     

Effect of certain bioactive plant extracts on clinical isolates of beta-lactamase producing methicillin resistant Staphylococcus aureus

Ethanolic extracts and some fractions from 10 Indian medicinal plants, known for antibacterial activity, were investigated for their ability to inhibit clinical isolates of beta-lactamase producing methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA). Synergistic interaction of plant extracts with certain antibiotics was also evaluated. The MRSA test strains were found to be multi-drug resistant and also exhibited high level of resistance to common beta-lactam antibiotics. These strains produced beta-lactamases, which hydrolyze one or other beta-lactam antibiotics, tested. The extract of the plants from Camellia sinensis (leaves), Delonix regia (flowers), Holarrhena antidysenterica (bark), Lawsonia inermis (leaves), Punica granatum (rind), Terminalia chebula (fruits) and Terminalia belerica (fruits) showed a broad-spectrum of antibacterial activity with an inhibition zone size of 11 mm to 27 mm, against all the test bacteria. The extracts from the leaves of Ocimum sanctum showed better activity against the three MRSA strains. On the other hand, extracts from Allium sativum (bulb) and Citrus sinensis (rind) exhibited little or no activity, against MRSA strains. The antibacterial potency of crude extracts was determined in terms of minimum inhibitory concentration (MIC) by the tube dilution method. MIC values, of the plant extracts, ranged from 1.3 to 8.2 mg/ml, against the test bacteria. Further, the extracts from Punica granatum and Delonix regia were fractionated in benzene, acetone and methanol. Antibacterial activity was observed in acetone as well as in the methanol fractions. In vitro synergistic interaction of crude extracts from Camellia sinensis, Lawsonia inermis, Punica granatum, Terminalia chebula and Terminalia belerica was detected with tetracycline. Moreover, the extract from Camellia sinensis also showed synergism with ampicillin.TLC of the above extracts revealed the presence of major phytocompounds, like alkaloids, glycosides, flavonoids, phenols and saponins. TLC-bioautography indicated phenols and flavonoids as major active compounds.     

Antimicrobial activity associated with extracellular matrices

Materials derived from extracellular matrices (ECMs) are being evaluated as scaffolds for surgical reconstruction of damaged or missing tissues. It is important to understand the susceptibility of these biological materials to bacterial infections. ECMs derived from porcine small intestinal submucosa (SIS) and urinary bladder submucosa (UBS) were found to possess antimicrobial activity. ECM extracts, obtained by digesting these acellular matrices in acetic acid, demonstrated antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Antimicrobial activity was determined using a minimal inhibitory concentration assay. Bacteriostatic activity was detected at protein concentrations of ECM extracts equivalent to 0.77-1.60 mg/mL. ECM extracts were found to inhibit bacterial growth for up to at least 13 h. The resulting extracts consisted of water-soluble peptides and proteins with molecular weights ranging from <4 to >100 kDa and lower molecular weight compounds, as determined by size exclusion liquid chromatography.     

Synthesis and antibacterial properties of peptidyl derivatives and cyclopeptides structurally based upon the inhibitory centre of human cystatin C. Dissociation of antiproteolytic and antibacterial effects

Cysteine protease-inhibiting proteins of the cystatin superfamily can inhibit the replication of certain viruses and bacteria. The inhibitory centre of human cystatin C, the most widely distributed human cystatin, comprises three peptide segments. The present work describes the synthesis and antibacterial activity of 27 new peptidyl derivatives or cyclopeptides based upon the aminoterminal segment Arg8-Leu9-Val10-Gly11. Fourteen of the new compounds displayed antibacterial activity against from 1 up to 9 of 17 clinically important bacterial species tested. Antiproteolytic activity of a compound was usually not required for its antibacterial capacity. Peptidyl diazomethanes generally had a very narrow antibacterial spectrum, inhibiting only Streptococcus pyogenes, whereas cyclopeptides and peptidyl derivatives of the general structure X-Arg-Leu-NH-CH(iPr)-CH2-NH-Y had a much wider spectrum. The most potent of these substances displayed approximately equal minimal inhibitory and bactericidal concentrations of about 20 microg/ml for both Staphylococcus aureus and S. pyogenes and were devoid of antiproteolytic activity. Several of the new substances could protect mice against lethal intraperitoneal challenge with S. pyogenes. Though their target remains to be disclosed, the group of substances here reported might be promising for the development of antibacterial drugs and the discovery of novel principles of action.     

In Vitro Antibacterial Activity of Bovine Dialyzable Leukocyte Extract

The rapidly developing resistance of many infectious pathogenic organisms to modern drugs has spurred scientists to search for new sources of antibacterial compounds. One potential candidate, bDLE (dialysis at 10 to 12 kDa cut-off) and its fractions (“S” and “L” by 3.5 kDa cut-off and I, II, III, and IV by molecular exclusion chromatography), was evaluated for antibacterial activity against pathogenic bacterial strains (Staphylococcus aureus, Streptococcus pyogenes, Lysteria monocytogenes, Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi) using standard antimicrobial assays. A minimum inhibitory concentration (MIC) of bDLE and its fractions was determined by agar and broth dilutions methods. Only bDLE and its “S” fraction had an effect upon all bacteria evaluated (MIC ranging from 0.29 to 0.62 U/ml), and the bactericidal and bacteriostatic effects (evaluated by MTT assay) were bacterial species-dependent. These results showed a remarkable in vitro antibacterial property of bDLE against several pathogenic bacteria.     

Antibacterial properties studies of trunk barks of Terminalia ivorensis (Combretaceae), a commercial and medicinal specie,on some methicillin-resistant Staphylococci spp strains

Background

Methicillin-resistant Staphylococcus aureus, Staphylococcus epidermidis and coagulase-negative Staphylococcus infections are a worldwide concern. Terminalia ivorensis, of Combretaceae family plant, is widely used traditional medicinal in Côte d''Ivoire to treat dermal diseases (affection in which Staphylococci are implied) including local inflammation and also to treat voice-loss.

Objectives

This study focused to investigate the effect in vitro of the extracts of trunk barks of Terminalia ivorensis on some methicillin/oxacillin-resistant strains of Staphylococcus aureus, S. epidermidis, coagulase-negative S. and reference strain of S. aureus ATCC 25923.

Methods

Antibacterial activity of aqueous, 70% ethanolic 70% and aqueous residue extracts was assessed using agar disc-diffusion method and liquid medium microdilution method in 96 multi-well micro-titer plates. This method led us to determine minimum inhibition concentration (M.I.C.) and minimum bactericidal concentration (M.B.C.). The presence of chemical groups major was detected qualitatively.

Results

Aqueous and 70% ethanolic 70% extracts showed significant activity against all the bacteria except aqueous residue when compared with the standard antibiotic oxacillin (5µg/ml). M.I.C. for aqueous and 70% ethanolic 70% extracts ranged from 0,83–16,67 mg/ml and 0,156–13,33 mg/ml respectively. Viable cell determination revealed the bactericidal nature of the two barks extracts. The 70% ethanolic 70% extract exhibited the highest activity according to the M.B.C. values. The phytochemical analysis indicates the presence of tannins, saponins, flavonoids, terpen/sterols, coumarins, polyphenols and traces of alkaloid.

Conclusion

The in-vitro antibacterial efficacy shown by the barks of this plant and his lushness in chimical compounds, would justify use of this one in the traditional treatment of some diseases of microbial origin. These compounds could be suggested to provide alternative solution to the development of new therapeutic agents.