抗感染聚乙烯材料表面生物被膜形成的抑制

背景:引起高分子材料相关感染的主要原因是材料表面形成了生物被膜,因此要预防此类感染不仅需要材料对表面接触的浮游菌有良好的抑制和杀灭效果,更需要抑制致病菌在表面形成生物被膜.目的:观察抗感染聚乙烯材料的抗菌效果以及在菌液中对材料表面生物被膜形成的抑制作用.设计、时间及地点:体外对比观察实验,于2007-01/2008-01在中科院理化所工程塑料国家工程研究中心完成.材料:有机抗菌剂为2,4,4'-三氯-2'-羟基二苯醚;无机抗菌剂为玻璃基银系抗菌剂;低密聚乙烯.方法:低密度聚乙烯与有机和无机两种抗菌剂混合后先挤出造粒,然后注塑成片.主要观察指标:①用活菌平板计数法测定材料的抗菌性能.②平板超声波法检测材料表面细菌密度及判断生物被膜的形成情况.结果:①两种改性抗菌材料对大肠杆菌和金黄色葡萄球菌都有良好的抗菌效果,抗菌率达到99.9%.②添加有机抗菌剂的试样可以在生物被膜成熟前显著杀灭样品表面的细菌,阻止细菌在其表面黏附和繁殖,从而抑制生物被膜形成.空白试样和无机抗菌试样表面均有大量细菌黏附.结论:有机抗感染聚乙烯材料对大肠杆菌和金黄色葡萄球菌有良好的抑菌作用,可抑制细菌在材料表面形成生物被膜.     

八种抗菌剂对粘附聚四氟乙烯导管上表皮葡萄球菌的活性

表皮葡萄球菌是医院感染的重要病原菌,尤其见于留置导管和其他假体装置病人。表皮葡萄球菌感染增加可能与使用假体装置增加有关。表皮葡萄球菌生长在塑料导管表面形成菌膜,于菌膜含有大量细菌体产生的相同粘质物。粘质物产生被认为是表皮葡萄球菌提高抵抗抗菌剂的一种机理,但表皮葡萄球菌菌膜抗性因素和机理未明确解释。研究视表皮葡萄球菌,导管和抗菌剂之间是相互作用的两个方面,第一,普通生物材料聚四氟乙烯对抗表皮葡萄球菌抗菌剂活性的影响;第二,粘附聚四氟乙烯的表皮葡萄球菌(产粘质和非产粘质菌株)对同一抗菌剂的易感性。作者用两种临床分离的表皮葡萄球菌;     

纳米载银磷酸锆抗菌聚氨酯的抗菌性能

背景:聚氨酯材料具有优异的物理和化学性能,良好的生物相容性和抗凝血性能,且易加工成形,但聚氨酯制造的人工器官容易受到细菌等微生物的入侵。目的:观察纳米载银无机抗菌剂对聚氨酯抗菌性能的影响。方法:将纳米载银无机抗菌剂RHA-2,按0%(空白对照组),0.5%,1%,1.5%,2%,2.5%,5%比例添加到聚氨酯中。采用薄膜密着法检测抗菌聚氨酯对金黄色葡萄球菌、大肠杆菌的抑菌作用,并分析比较抗菌剂添加比例与聚氨酯抗菌性能的相关性。结果与结论:添加纳米载银无机抗菌剂的聚氨酯对金黄色葡萄球菌、大肠杆菌具有良好的抑菌作用。抗菌剂添加比例0.5%~5%组对金黄色葡萄球菌的抑菌率分别为80.23%,91.32%,95.23%,99.19%,99.87%,99.93%,对大肠杆菌的抑菌率分别为76.70%,86.96%,92.92%,95.43%,99.34%,99.87%,显示抗菌性能随抗菌剂添加比例的上升而明显提高。表明纳米载银无机抗菌剂的添加赋予了聚氨酯优异的抗菌性能,且从抗菌角度出发,推荐纳米载银无机抗菌剂在聚氨酯中的添加比例不应低于1.5%。     

纳米载银磷酸锆抗菌聚氨酯的抗菌性能

背景：聚氨酯材料具有优异的物理和化学性能,良好的生物相容性和抗凝血性能,且易加工成形,但聚氨酯制造的人工器官容易受到细菌等微生物的入侵。目的：观察纳米载银无机抗菌剂对聚氨酯抗菌性能的影响。方法：将纳米载银无机抗菌剂RHA-2,按0%（空白对照组）,0.5%,1%,1.5%,2%,2.5%,5%比例添加到聚氨酯中。采用薄膜密着法检测抗菌聚氨酯对金黄色葡萄球菌、大肠杆菌的抑菌作用,并分析比较抗菌剂添加比例与聚氨酯抗菌性能的相关性。结果与结论：添加纳米载银无机抗菌剂的聚氨酯对金黄色葡萄球菌、大肠杆菌具有良好的抑菌作用。抗菌剂添加比例0.5%~5%组对金黄色葡萄球菌的抑菌率分别为80.23%,91.32%,95.23%,99.19%,99.87%,99.93%,对大肠杆菌的抑菌率分别为76.70%,86.96%,92.92%,95.43%,99.34%,99.87%,显示抗菌性能随抗菌剂添加比例的上升而明显提高。表明纳米载银无机抗菌剂的添加赋予了聚氨酯优异的抗菌性能,且从抗菌角度出发,推荐纳米载银无机抗菌剂在聚氨酯中的添加比例不应低于1.5%。     

高分子材料的表面菌膜

背景:医疗器械尤其是高分子介入性导管引起的导管相关型感染是院内感染的主要途径之一,而导致人体感染的真正原因是器械或导管表面形成了菌膜.目的:对菌膜的形成机制,影响菌膜形成和发展的因素以及当前抑制菌膜形成的常用方法进行综述.方法:以"菌膜,生物膜,生物被膜","高分子,塑料,橡胶"和"biofilm,polymer,plastics,rubber"为检索词在medline、life sciences、Toxline plus、Derwent drug file、CBMDisc、CMCC等数据库和www.ncbi.nlm.nih.gov、www.uspto.gov、www.patent.com.cn等网站进行检索,得到相关国内外文献214篇.排除陈旧和内容类似文献,选择43篇文献进行综述.结果与结论:目前对菌膜在高分子器械表面形成过程和形成机制已经基本阐述清晰,但迄今为止,菌膜的研究多集中从微生物学、医学、基因角度进行,对菌膜的防治也是直接从利用抗生素的抑制方面考虑,文章着重从材料角度探讨抑制菌膜的可能途径及其在临床应用的可能性.     

高分子材料的表面菌膜

背景：医疗器械尤其是高分子介入性导管引起的导管相关型感染是院内感染的主要途径之一,而导致人体感染的真正原因是器械或导管表面形成了菌膜。目的：对菌膜的形成机制,影响菌膜形成和发展的因素以及当前抑制菌膜形成的常用方法进行综述。方法：以＂菌膜,生物膜,生物被膜＂,＂高分子,塑料,橡胶＂和＂biofilm,polymer,plastics,rubber＂为检索词在medline、life sciences、Toxline plus、Derwent drug file、CBMDisc、CMCC等数据库和www.ncbi.nlm.nih.gov、www.uspto.gov、www.patent.com.cn等网站进行检索,得到相关国内外文献214篇。排除陈旧和内容类似文献,选择43篇文献进行综述。结果与结论：目前对菌膜在高分子器械表面形成过程和形成机制已经基本阐述清晰,但迄今为止,菌膜的研究多集中从微生物学、医学、基因角度进行,对菌膜的防治也是直接从利用抗生素的抑制方面考虑,文章着重从材料角度探讨抑制菌膜的可能途径及其在临床应用的可能性。     

抗菌生物材料的抗细菌黏附能力

背景：由于生物材料和人工器官在临床应用逐渐增多,给临床患者进行治疗疾病的同时还存在着一些问题,最为常见的是生物材料植入人体后引起的细菌感染。目的：探讨生物材料在抗细菌黏附中的作用,抗菌生物材料的分类及特点。方法：生物材料在机体引起各种感染的原因是由于细菌生物膜的形成,防止生物材料置入后感染的关键是抑制细菌在生物材料表面的黏附以及防止细菌在生物材料表面形成细菌生物膜。细菌表面黏附重点是改变细菌自身的特性和材料表面的物理化学性质,通过改变材料的物理化学性质来减小材料和细菌之间的相互作用力,主要采用化学接枝法、等离子体法、气相沉淀法等。预防细菌黏附首先要增强机体的免疫防御能力,其次要使界面快速的被组织覆盖,形成严密的连结界面。结果与结论：抗菌生物材料分为无机抗菌生物材料、天然抗菌生物材料和合成抗菌生物材料,无机抗菌材料以银系材料为主,天然抗菌生物材料以壳聚糖研究为较多,合成抗菌生物材料以季铵盐类材料为代表,各种材料都具有各自的优缺点,需要进一步的体内外基础实验和临床研究来验证和推动抗菌生物材料的发展。     

ICU医院感染与置入性导管中细菌生物膜的相关研究

目的:研究重症监护病房(intensive care unit,ICU)置入性导管形成细菌生物膜的状况,了解导管中的生物膜对ICU医院感染的影响,为寻求控制置入性导管细菌所致医院感染的有效措施提供依据.方法:收集ICU病房置入性导管,通过阿利新蓝与刚果红联合染色快速鉴定细菌生物膜形成,导管置入液体培养基中模拟液态持续流动的环境,观察导管内侧面形成的生物膜结构.结果:阿利新蓝-刚果红染色细菌生物膜呈深红色;导管材料内表面细菌附着并有纤维素样物质交联形成生物膜.附着的细菌主要有铜绿假单胞菌、鲍曼不动杆菌、大肠杆菌及葡萄球菌等.结论:阿利新蓝染色法可用于快速检测细菌生物膜的形成,置入性导管细菌生物膜的形成与ICU医院感染密切相关.     

结核杆菌黏附不同人工关节假体材料的能力研究

背景：细菌黏附在假体表面大量繁殖并形成致密的生物膜,药物难以进入将其杀灭是人工关节置换后感染难治及复发的主要原因。目的：观察不同人工关节假体材料性质、表面对结核杆菌黏附能力的影响。方法：取钛合金和钴铬钼合金试样（均分光滑面和粗糙面两种）,分别将结核杆菌与表皮葡萄球菌（对照菌液）经传代培养后由FITC标记,制成菌液;将菌液与试样37℃共同培养24h;用荧光显微镜和电镜扫描观察两种细菌在上述4种不同试样的黏附情况。结果与结论：表皮葡萄球菌和结核杆菌在钴铬钼合金表面的黏附面积均大于在钛合金表面的黏附面积;在同种材料中粗糙面比光滑面更容易发生细菌黏附;两种材料表面均可见表皮葡萄球菌形成生物膜,而结核杆菌则无生物膜形成。表明结核杆菌在钴铬钼合金、钛合金表面的黏附能力较差;材料性质和材料表面粗糙程度均对结核杆菌黏附力产生巨大影响;结核杆菌在钴铬钼合金和钛合金表面并无生物膜形成。     

人工瓣膜材料细菌黏附与细菌生长的关系

背景：有研究表明引起人工瓣膜置换后心内膜炎的初始原因是细菌黏附在生物材料表面，人工瓣膜材料细菌黏附与细菌生长的关系值得研究。 目的：通过体外实验观察人工瓣膜置换后心内膜炎常见致病菌对不同人工瓣膜材料体外黏附与细菌生长的关系，分析人工瓣膜材料对细菌生长的影响。 设计、时间及地点：重复测量观察，实验于2001—01／03在云南省肿瘤医院胸心血管外科完成。 材料：涤纶购自苏州织带厂人造血管研究室，聚四氟乙烯由美国亚利桑那州Teflon-GoreTexW.L．Gore＆Associates，Inc．提供，热解碳片购自四川联合大学生物材料系；金黄色葡萄球菌，大肠杆菌，表皮葡萄球菌及绿脓杆菌为实验室自备。 方法：采用平板菌落计数法、^125I标记细菌放射性测定法测定金黄色葡萄球菌、表皮葡萄球菌、大肠杆菌和绿脓杆菌在人工瓣膜材料涤纶、热解碳、聚四氟乙烯环境中的生长曲线，以无材料为空白对照，培养时间30h，从0h开始每隔2h进行细菌浓度测评，同时测定4种细菌对人工瓣膜材料涤纶、热解碳、聚四氟乙烯的黏附情况。 主要观察指标：4种菌落在人工瓣膜材料涤纶、热解碳、聚四氟乙烯中的生长曲线及黏附情况。 结果：①在同一时间点同一细菌在涤纶、聚四氟乙烯、热解碳环境中生长浓度之间比较差异无显著性意义伊〉0．05），4种细菌在不同人工瓣膜材料中的生长曲线与未放生物材料比较差异无显著性意义（P〉0．05）。②不同细菌对不同材料的黏附程度不同，金黄色葡萄球菌对涤纶黏附最强；表皮葡萄球菌对热解碳黏附最强；大肠杆菌对涤纶的黏附最强：绿脓杆菌对涤纶的黏附在12h时达高峰，但很快呈下降趋势，对热解碳、聚四氟乙烯黏附持续维持在高水平状态。4种细菌对材料的黏附不随时间推移而持续增高或恒定不变。 结论：在同一种细菌生长曲线的不同时期，对同一种材料的黏附变化较大。人工瓣膜材料对细菌生长周期影响不大。     

无机载银抗菌剂在口腔修复中的研究应用现状

背景:口腔环境是有菌环境,各种修复治疗的效果面临着来自微生物的挑战,治疗的成败在一定程度上取决于材料的抗菌性能。银系无机抗菌剂由于抗菌谱广,生物安全性高,不易产生耐药性等特点,成为众多学者研究的热点。目的:综述无机载银抗菌剂在口腔修复材料中的应用及研究进展,为进一步的临床应用提供理论基础。方法:应用计算机检索CNKI数据库、PubMed数据库、OVID数据库等1990-01/2011-04有关银系无机抗菌剂及其在口腔修复中的应用的相关文章。纳入与无机载银抗菌剂及其在口腔修复中的应用研究密切相关的近期发表或在权威杂志上发表的文章,共29篇入选分析。结果与结论:银是一种理想的抗菌材料,对口腔常见致病菌如白色念珠菌、变异链球菌,乳酸杆菌等具有良好的抗菌效果,将其应用到口腔修复材料中具有广阔的临床应用前景。但银离子不稳定,易变色,在修复材料的改性研究中,克服材料的氧化变色、减小对材料理化性能的影响及其材料的临床应用与评价等问题仍有待于进一步研究。     

Roles of chitosan in synthesis,antibacterial and anti-biofilm properties of bionano silver and gold

Antibiotic-resistance and bacterial bioburden on wound surfaces are the significant challenges to wound healing. Silver and gold nanoparticles (are termed as AgNPs and AuNPs) have been investigated as alternative antimicrobial agents to combat antibiotic-resistant bacterial infections owing to their antibacterial and anti-biofilm activities. Chitosan (CS) has largely been used in nanoparticle synthesis as a stabilizing or capping agent. In this study, AgNPs and AuNPs were synthesized using different concentrations of aqueous extract of tiger milk mushroom (Lignosus rhinocerotis) (WETMM) and CS as reducing and stabilizing agent, respectively. Particle size and morphology of both were determined by dynamic light scattering (DLS) method and transmission electron microscopic analysis (TEM). FTIR analysis was conducted to determine the interactions between nanoparticle precursors. The observed peaks at 450 nm and 534–565 nm using a spectrophotometer were corresponded to the surface Plasmon resonance of AgNPs and AuNPs respectively, indicating the formation of respective nanoparticles. FTIR analysis confirmed the role of WETMM as a reducing agent and CS as a stabilizer of AgNPs and AuNPs. Faster formation of nanoparticles was observed besides an increase in particle size when higher CS concentrations were used. TEM micrographs revealed the spherical shape of most nanoparticles with particle sizes in the range of 4 to 58 nm and 18 to 28 nm for AgNPs and AuNPs, respectively. Both nanoparticles exhibited antimicrobial activity against Gram-positive and -negative bacteria, with AgNPs showing a superior antibacterial efficacy than AuNPs. Both microbroth dilution and agar well diffusion assays indicated that CS was an important component to facilitate antibacterial activity for AuNPs. Contrarily, CS stabilization did not enhance the antibacterial efficacy of AgNPs. CS-stabilized AgNPs and AuNPs achieved biofilm inhibition of 53.21% and 79.39% for Pseudomonas aeruginosa and 48.71% and 48.16% for Staphylococcus aureus, respectively. Similarly, CS stabilization enhanced the anti-biofilm activity of AuNPs but no such effect was seen for AgNPs. In conclusion, CS-stabilized AgNPs and AuNPs possess both antimicrobial and anti-biofilm activities. However, CS acted differently when combined with AgNPs and AuNPs, needing further investigation and optimization to improve the antimicrobial activity of both nanoparticles.

Biosynthesis of silver and gold nanoparticles using extract of tiger milk mushroom and stabilized by chitosan were effective at inhibiting biofilm formation and growth of Pseudomonas aeruginosa and Staphylococcus aureus, common biofilm-forming pathogens on wound surfaces.     

Susceptibility of Actinobacillus actinomycetemcomitans to six antibiotics decreases as biofilm matures

OBJECTIVES: Actinobacillus actinomycetemcomitans is a major causative agent of chronic and aggressive periodontitis. Freshly isolated strains of A. actinomycetemcomitans display rough-type colonies and initiate biofilm formation on glass surfaces. The purpose of this study was to determine the antibiotic susceptibility of A. actinomycetemcomitans biofilm during different phases of maturation. METHODS: Using 96-well microtitre plates, we determined the antibiotic susceptibility of rough-type strain 310a to concentrations from 0.1 to 10 mg/L each of erythromycin, ofloxacin, ampicillin, cefalexin, tetracycline and minocycline during biofilm formation. Antibiotics were added at the start of the culture (early phase) and after 24 h of cultivation (mature phase). RESULTS: Adding 10 mg/L of ampicillin, 10 mg/L of cefalexin, 0.1 or 1 mg/L of tetracycline, or 0.1 mg/L of minocycline significantly inhibited 310a biofilm formation in the early phase, but not in the mature phase. Although adding 10 mg/L of erythromycin, tetracycline or minocycline reduced biofilm development in the early phase, it enhanced 310a biofilm development in the mature phase. Ofloxacin exerted a strong inhibitory effect in both the early and mature phases of biofilm formation throughout all experiments. CONCLUSIONS: The present study demonstrated that the susceptibility of A. actinomycetemcomitans to many antibiotics decreased after biofilm maturation.     

多种抗菌剂抗菌性及混合加入复合树脂的抗菌性能

背景：抗菌剂如纳米载银、季胺盐、磷酸钙等,具有良好的抗菌作用,能对口腔中常见致病菌的生长起到抑制作用,将抗菌剂作为填料加入复合树脂,制成抗菌性复合树脂,是当前研究的一个热点. 目的：综述近年国内外关于抗菌性复合树脂的研究情况. 方法：以“复合树脂,抗菌剂,银离子,季胺盐,磷酸钙”为中文关键词,以“composite resin, antibacterial agent, silver ion, amine salt, calcium phosphate”为英文关键词,采用计算机检索1995年1月至2012年5月中国知网数据库 CNKI、PubMed 数据库和维普中文科技期刊数据库、万方数据库、Web of Science 期刊引文索引数据库及Nature数据库有关抗菌性复合树脂的文献. 结果与结论：抗菌剂分为天然、有机、无机、有机高分子抗菌剂.目前研究较多的有纳米载银抗菌性复合树脂、季铵盐抗菌性复合树脂、纳米磷酸钙抗菌性复合树脂等.体内外实验表明,抗菌剂的加入使复合树脂具有较强的抗菌性能,可阻断细菌的生长过程,进而减少继发龋的发生,延长修复体的寿命,且不改变复合树脂的理化性质.最新的研究中将多种不同性质的抗菌剂混合加入复合树脂中得到了具有更强抗菌性、机械性能的抗菌性复合树脂,这也将成为今后研究新型抗菌性复合树脂的重要方向.     

Antibacterial effect of boron nitride flakes with controlled orientation in polymer composites

Boron nitride (BN) is a stable 2D material with physiochemical properties similar to graphene-based nanomaterials. We have recently demonstrated that vertically aligned coatings of graphene-based nanomaterials provide strong antibacterial effects on various surfaces. Here we investigated whether BN, a nanomaterial with extensive similarities to graphene, might exhibit similar antibacterial properties. To test this, we developed a novel composite material using BN and low density polyethylene (LDPE) polymer. The composite was extruded under controlled melt flow conditions leading to highly structured morphology, with BN oriented in the extrusion flow direction. Nanocomposite extruded surfaces perpendicular to the flow direction were etched, thus exposing BN nanoparticles embedded in the matrix. The antimicrobial activity of extruded samples was evaluated against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus aureus by the colony forming units (CFUs) counting method. Furthermore, the bactericidal effect of oriented BN against E. coli and S. aureus was evaluated by scanning electron microscopy (SEM) and live/dead viability assay. Our results suggest that BN nanoflakes on the extruded BN/LDPE composite physically interact with the bacterial cellular envelope, leading to irreparable physical damage. Therefore, we propose that BN–polymer composites might be useful to develop polymer based biomedical devices protected against bacterial adhesion, and thus minimize device associated infections.

Vertically oriented boron nitride flakes on a polymer surface exhibit bactericidal activity.     

Reduction of Streptococcus mutans adherence and dental biofilm formation by surface treatment with phosphorylated polyethylene glycol

Initial attachment of the cariogenic Streptococcus mutans onto dental enamel is largely promoted by the adsorption of specific salivary proteins on enamel surface. Some phosphorylated salivary proteins were found to reduce S. mutans adhesion by competitively inhibiting the adsorption of S. mutans-binding salivary glycoproteins to hydroxyapatite (HA). The aim of this study was to develop antiadherence compounds for preventing dental biofilm development. We synthesized phosphorylated polyethylene glycol (PEG) derivatives and examined the possibility of surface pretreatment with them for preventing S. mutans adhesion in vitro and dental biofilm formation in vivo. Pretreatment of the HA surface with methacryloyloxydecyl phosphate (MDP)-PEG prior to saliva incubation hydrophilized the surface and thereby reduced salivary protein adsorption and saliva-promoted bacterial attachment to HA. However, when MDP-PEG was added to the saliva-pretreated HA (S-HA) surface, its inhibitory effect on bacterial binding was completely diminished. S. mutans adhesion onto S-HA was successfully reduced by treatment of the surface with pyrophosphate (PP), which desorbs salivary components from S-HA. Treatment of S-HA surfaces with MDP-PEG plus PP completely inhibited saliva-promoted S. mutans adhesion even when followed by additional saliva treatment. Finally, mouthwash with MDP-PEG plus PP prevented de novo biofilm development after thorough teeth cleaning in humans compared to either water or PP alone. We conclude that MDP-PEG plus PP has the potential for use as an antiadherence agent that prevents dental biofilm development.     

Effects of bovine serum albumin on light activated antimicrobial surfaces

Bovine serum albumin (BSA) is currently recommended as an interfering substance to emulate organic soiling, in evaluating the efficacy of disinfectants. The European Standard recommends 0.03% BSA to test clean conditions and 0.3% for dirty conditions. Reactive oxygen species are known to exert excellent antimicrobial activity with low specificity against a broad range of pathogens. Herein, we present our data from the first study of the effects of the addition of BSA on the antibacterial activity of light activated antimicrobial surfaces. Light activated antimicrobial surfaces were made from polyurethane swell-encapsulated with gold nanoparticles (AuNPs) coated with the light active triarylmethane dye, crystal violet (PU-AuNP-CV). The antibacterial efficacy of the antimicrobial substrates was tested against two strains of Staphylococcus aureus 8325-4, a well-characterised laboratory strain and MRSA 4742, a recent clinical isolate, in the presence of 0.1% to 1% BSA by irradiating the substrates with a fluorescent lamp (300 lux). After 6 hours of irradiation, the number of surviving bacteria was determined. The results showed that BSA reduced the antibacterial efficacy of all the PU-AuNP-CV surfaces with increasing BSA concentrations resulting in a progressive reduction in antibacterial activity towards the bacteria tested. However, the light activated surfaces did perform well at 0.1 and 0.25% BSA levels, showing they may have potential for real world environments with low levels of organic soiling.

In this work we demonstrate that our active surfaces still show antibacterial activity even with BSA at low light.