重组溶葡球菌酶的体外抗菌活性研究

目的：评价重组溶葡球菌酶对545株临床分离葡萄球菌的体外抗菌活性。方法：采用平皿二倍稀释法，测定重组溶葡球菌酶对545株葡萄球菌的最低抑菌浓度（MIC）；采用试管二倍稀释法和平皿计数法测定此酶对45株葡萄球菌的最低杀菌浓度（MBC）；采用不同浓度重组溶葡球菌酶不同时间的杀菌结果绘制杀菌曲线，检测其对4株受试葡萄球菌的动态杀菌趋势；此外，测定不同培养条件对MIC的影响。结果：此酶对257株金葡球菌具有较强的体外抗菌活性，对288株凝固酶阴性葡萄球菌的抗菌活性相对较弱；结合MBC和杀菌曲线结果，可以判断此酶对敏感菌为快速杀菌作用，并呈浓度依赖性；pH，细菌接种量及高浓度血清蛋白对MIC有一定影响，受试浓度的二价金属离子对MIC影响不明显。结论：重组溶葡球菌酶主要对金葡菌体现强大的抗菌活性，对耐甲氧西林金葡菌（MRSA）和甲氧西林敏感金葡菌（MSSA）的抗菌作用没有明显差别，有进一步研究的价值。     

耐药葡萄球菌及其感染的治疗

葡萄球菌为革兰阳性球菌，多数为非致病菌，少数可导致疾病。除金黄色葡萄球菌(金葡菌)产生血浆凝固酶外，其它菌种凝固酶皆属阴性，称为凝固酶阴性葡萄球菌(CNS)，其中较常见的致病菌为表皮葡萄球菌(表葡菌)、溶血葡萄球菌和腐生葡萄球菌(腐葡菌)。     

溶葡萄球菌酶对耐甲氧西林金黄色葡萄球菌的体外抗菌活性

目的 :探讨溶葡萄球菌酶对万古霉素低敏耐甲氧西林金黄色葡萄球菌 (MRSA)的抗菌活性。方法 :琼脂稀释法测定万古霉素和溶葡萄球菌酶对MRSA的最低抑菌浓度 (MIC) ,棋盘法检测 2药联合抑菌作用。结果 :万古霉素对其敏感或低敏MR SA的MIC90 分别为 2mg·L- 1,8mg·L- 1;溶葡萄球菌酶对万古霉素敏感或低敏MRSA的MIC90 分别为 0 .2 5mg·L- 1,0 .5mg·L- 1;2药联合对其敏感株和低敏株的FIC90 (FIC为联合抑菌分数 )较万古霉素单独应用时MIC90 分别减少 4倍和 8倍 ,较溶葡萄球菌酶单独应用时均减少 4倍。FIC指数均小于0 .5。结论 :溶葡萄球菌酶对万古霉素敏感或低敏的MRSA均有良好的体外抗菌活性     

葡萄球菌感染的治疗

葡萄球菌为临床常见的致病菌,属细球菌科,可分为凝固酶阳性的金黄色葡萄球菌(金葡菌)和凝固酶阴性的表皮葡萄球菌(表葡菌)及腐生葡萄球菌(腐葡菌),后两者可藉对新生霉素的敏感度和甘露醇发酵情况相区别。金葡菌的致病性强,因为它能产生多种毒素和酶(有溶血素、杀白细胞素、肠毒素、表皮剥脱毒素、“导致中毒性休克综合征的毒素”、产红毒素、血浆凝固酶、透明质酸酶、葡萄球菌激酶、过氧化氢酶、溶纤维蛋白酶、磷酸酶     

骨伤科分离金黄色葡萄球菌耐药性与细菌生物被膜的关系研究

目的 探讨金黄色葡萄球菌生物被膜与耐药性的关系分析。方法 收集2020年10月至2022年3月阳江市中医医院骨伤科分离的金黄色葡萄球菌进行药敏检测并通过结晶紫染色法分离生物被膜及检测生物被膜的形成情况,对生物被膜的形成情况及其药敏结果进行统计学分析。结果 本研究共收集87株金黄色葡萄球菌,其中不具有生物被膜的有13株,占14.94%,其中分离生物被膜强度为阳性的菌株有64株,占73.57%,分离生物被膜强度为强阳性的菌株有10株,占11.49%。金黄色葡萄球菌具有较强的生物被膜形成能力。除大环内酯类、糖肽类抗菌药物外,生物被膜强度为强阳性的金黄色葡萄球菌的耐药率高于生物被膜强度为阳性的金黄色葡萄球菌,生物被膜强度为阳性的金黄色葡萄球菌的耐药率高于无生物被膜形成的金黄色葡萄球菌。结论 金黄色葡萄球菌生物被膜的形成与其耐药性有密切联系,但生物被膜的耐药机制目前尚不明确,有待进一步研究。     

重组溶葡球菌酶治疗小型猪皮肤烫伤MRSA感染*

目的:评价重组溶葡球菌酶对实验性皮肤烫伤耐甲氧西林金葡菌(MRSA)感染的抗感染作用。方法:用中国实验用小型猪建立局部皮肤烫伤后MRSA感染模型,不同处理组创面治疗3 d或7 d后,进行痂下组织活菌计数及组织病理学观察,评价药物抗菌疗效。结果:重组溶葡球菌酶对烫伤皮肤的感染细菌有较好的清除作用,治疗后d 4和d 8高浓度(1 000 U.mL-1)组创面活菌计数[(5.94±0.61)和(4.03±0.75)lg CFU.g-1组织]均明显低于空白对照组[(7.48±0.33)和(6.32±0.60)lg CFU.g-1组织]和阳性药SD-Ag组创面[(7.44±0.19)和(5.29±0.40)lg CFU.g-1组织],P<0.05或P<0.01;治疗后d 8,中浓度(330 U.mL-1)组创面活细菌计数[(5.10±0.29)lg CFU.g-1组织]明显低于空白对照组创面[(6.32±0.60)lg CFU.g-1组织],P<0.05。组织病理学观察也反映了重组溶葡球菌酶的良好疗效。结论:重组溶葡球菌酶对MRSA引起的实验性皮肤烫伤感染有良好的抗感染作用。     

左氧氟沙星与头孢硫脒合用对金黄色葡萄球菌、表皮葡萄球菌、粪肠球菌体外抗菌活性研究

目的评价左氧氟沙星与头孢硫脒联合应用对金黄色葡萄球菌、表皮葡萄球菌和粪肠球菌的体外联合抗菌作用.方法采用棋盘法设计,微量肉汤稀释法测定其UIC值,计算FIC指数.结果左旋氧氟沙星与头孢硫脒联合应用后,左旋氧氟沙星对金黄色葡萄球菌、表皮葡萄球菌、粪肠球菌、HRSA、NRSE的HIC50均有明显降低,同样头孢硫脒对金色葡萄球菌、表皮葡萄球菌、粪肠球菌、HRSA、HRSE的NICm亦显著下降.FIC指数范围主要在0～1.结论左氧氟沙星与头孢硫脒药物联合应用,对金黄色葡萄球菌、表皮葡萄球菌和粪肠球菌的体外联合抗菌作用以协同和相加为主.     

丁香酚对压疮致病菌金黄色葡萄球菌及其耐药菌的抑菌作用及机制

目的 明确丁香酚对压疮致病菌金黄色葡萄球菌Staphylococcus aureus的体外抑菌作用及机制。方法 采用微量肉汤稀释法和和生长曲线确定丁香酚对金黄色葡萄球菌的抑菌活性;通过碱性磷酸酶（AKP）活性、细菌核酸蛋白泄漏的检测,细菌超微结构的扫描和透射电镜观察以及菌体对碘化丙啶（PI）和N-菲酰-次巯基-L-丙氨酸（NPN）的摄取来探讨丁香酚处理后金黄色葡萄球菌细胞膜的通透性和完整性;以结晶紫染色法和实时荧光定量PCR法研究丁香酚对菌体生物被膜（BF）生成、成熟以及菌体黏附、侵袭相关毒力因子表达水平的影响。结果 丁香酚对金黄色葡萄球菌标准菌和耐甲氧西林金葡菌（MRSA）的最低抑菌浓度（MIC）分别为0.25、0.125 mg/mL。丁香酚处理后可以提高细菌培养液中核酸、蛋白浓度及AKP的活性;菌体出现皱缩和破裂,菌体内膜和外膜中分别出现PI和NPN荧光,菌体结构破坏和荧光强度与丁香酚浓度呈正相关。丁香酚能够抑制金黄色葡萄球菌菌株BF的生成,且对成熟BF具有明显清除作用,显著降低BF生成相关基因agr A、sar A、cid A和icaA及黏附因子clf A、clf B、fnb A...     

溶葡球菌酶研究进展

溶葡球菌酶是一种最初从模仿葡萄球菌培养物中分离的含Zn2+金属蛋白酶,具有潜在的抗葡萄球菌药用价值。此文综述了溶葡球菌酶在理化性质、酶学性质、细菌生理学功能、抗菌作用机制、基因克隆与表达以及药效学活性等领域的研究进展,并结合溶葡球菌酶的研究现状对其发展趋势进行展望。     

左氧氟沙星与头孢硫脒合用对金黄色葡萄球菌、表皮葡萄球菌、粪肠球菌体外抗菌活性研究

目的:评价左氧氟沙星与头孢硫脒联合应用对金黄色葡萄球菌、表皮葡萄球菌和粪肠球菌的体外联合抗菌作用.方法:采用棋盘法设计,微量肉汤稀释法测定其UIC值,计算FIC指数.结果:左旋氧氟沙星与头孢硫脒联合应用后,左旋氧氟沙星对金黄色葡萄球菌、表皮葡萄球菌、粪肠球菌、HRSA、NRSE的HIC50均有明显降低,同样头孢硫脒对金色葡萄球菌、表皮葡萄球菌、粪肠球菌、HRSA、HRSE的NICm亦显著下降.FIC指数范围主要在0～1.结论:左氧氟沙星与头孢硫脒药物联合应用,对金黄色葡萄球菌、表皮葡萄球菌和粪肠球菌的体外联合抗菌作用以协同和相加为主.     

单宁酸联合氟康唑抑制金黄色葡萄球菌与白念珠菌混合生物膜的作用及机制研究

摘要：目的 分析单宁酸联合氟康唑降低金黄色葡萄球菌与白念珠菌混合生物膜的作用及其机制。方法 收集2019年临床 分离的3株耐甲氧西林金黄色葡萄球菌(MRSA),分别命名为SA1,SA2和SA3;利用分光光度法检测单宁酸单独或联合氟康唑对 金黄色葡萄球菌与白念珠菌DAY185混合菌群生长能力的影响,进一步采用结晶紫染色法测定对混合生物膜形成能力的影响; 扫描电子显微镜观察单宁酸联合氟康唑对混合生物膜结构影响;实时荧光定量PCR(qRT-PCR)检测白念珠菌DAY185生物膜形成 相关基因(ALS1、ALS3和RBT1)和SA1生物膜形成相关基因(icaA、sarA和cidA)的表达量变化。结果 单宁酸可以降低金黄色葡萄 球菌与白念珠菌混合菌群的生长能力和混合生物膜形成能力,当联合氟康唑时抑制作用更加明显;扫描电子显微镜显示单宁酸 联合氟康唑可以明显减少金黄色葡萄球菌在白念珠菌菌丝上的黏附;qRT-PCR结果表明：单宁酸联合氟康唑主要可以降低混合 生物膜中白念珠菌ALS3基因(P＜0.05)和金黄色葡萄球菌icaA和sarA基因(P＜0.05)的表达量。结论 单宁酸联合氟康唑可以降低 金黄色葡萄球菌与白念珠菌混合生物膜的形成,其机制主要通过降低白念珠菌菌丝形成相关基因ALS3和金黄色葡萄球菌黏附相 关基因icaA和sarA的表达水平。     

Combined efficacy of clarithromycin plus cefazolin or vancomycin against Staphylococcus aureus biofilms formed on titanium medical devices

In this study, we investigated the in vitro efficacy of clarithromycin (CLA) combined with cefazolin (CFZ) or vancomycin (VCM) against Staphylococcus aureus biofilms formed on titanium devices in order to confirm the efficacy of eradication therapies against device-related infection. The distribution of CLA in muscle tissue surrounding bone was also investigated by liquid chromatography/tandem mass spectrometry in 10 orthopaedic patients. Biofilm formation and eradication of S. aureus were monitored by scanning electron microscopy and using double-staining dyes, respectively. Although S. aureus biofilms were not eradicated by CLA, CFZ or VCM alone, CLA combined with CFZ or VCM destroyed biofilms, and S. aureus eradication was clearly observed 72 h later. This in vitro study showed that treatment with CLA plus CFZ or VCM destroyed staphylococcal biofilms formed on medical devices and eradicated S. aureus.     

罗红霉素与乙酰螺旋霉素对眼部金黄色葡萄球菌生物膜的影响

目的:比较罗红霉素与乙酰螺旋霉素对眼部金黄色葡萄球菌生物膜的影响及与环丙沙星合用的抗菌协同作用。方法:用0.22μm微孔膜构建金黄色葡萄球菌生物膜模型;测定罗红霉素、乙酰螺旋霉素及环丙沙星的最低抑菌浓度(MIC)值;银染金黄色葡萄球菌生物膜,扫描电镜(SEM)观察生物膜形态结构,连续稀释法进行活菌计数。结果:生物膜(BF)可在7 d内稳定形成,1/16MIC、1/4MIC浓度罗红霉素显著减少单用环丙沙星组中的BF活菌数(P<0.05),乙酰螺旋霉素没有明显作用。结论:罗红霉素能显著提高环丙沙星对BF中金黄色葡萄球菌的抗菌活性。     

大环内酯类药物对铜绿假单胞菌生物膜形成的影响

采用聚碳酸酯过滤膜或聚丙烯酰胺膜制备铜绿假单胞菌生物膜,计数滤膜菌落并用扫描电镜观察,研究大环内酯类及抗铜绿假单胞菌药物对铜绿假单胞菌生物形成的影响。结果表明与未经药物作用的滤膜菌落计数比较,阿尔霉素2mg/L和红霉素2mg/L可使生物膜内细菌由10^10CFU/cm^2降至10^3.3和10^3.7CFU/cm^2;阿奇霉素（2mg/L)分别与头孢他啶（0．0625mg/L)、亚胺培南（0．5mg/L）、美洛培南（0．25mg/L）、阿米卡星（0．0625mg/L )、环丙沙星（0．004mg/L）合用后,生物膜内细菌降至10^1.5-10^3.8CFU/cm^2;红霉素与上述药物合用后,生物膜内细菌降至10^2.8-10^5.5CFU/cm^2;麦迪霉素32mg/L、抗铜绿假单胞菌药物单用或两者联合应用,菌量为10^8.1-10^11.5CFU/cm^2。扫描电镜观察与菌落计数结果一致。表明红霉素、阿奇霉素能抑制铜绿假单胞菌生物膜的生成;麦迪霉素及五种抗铜绿假单胞菌药物对生物膜的形成无抑制作用。     

Activity of moxifloxacin on biofilms produced in vitro by bacterial pathogens involved in acute exacerbations of chronic bronchitis

The aim of this study was to assess whether moxifloxacin is able to inhibit the synthesis of and to disrupt biofilms produced in vitro by bacterial pathogens involved in acute bacterial exacerbations of chronic bronchitis. Three strains each of Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, Staphylococcus aureus and Escherichia coli recently isolated from clinical respiratory specimens and capable of slime production were used. Biofilm formation on polystyrene plates was quantified spectrophotometrically by established methodologies. Moxifloxacin (0.5 mg/L) inhibited slime synthesis by >70% in S. aureus, H. influenzae and S. pneumoniae, 45-70% in E. coli and 35-70% in M. catarrhalis. Disruption of pre-formed structures was also promoted by moxifloxacin both for initial (5h) and mature (48 h) biofilms. Drug concentrations reached during therapy (0.5-4 mg/L) resulted in a breakdown of initial biofilm of 60-80% in H. influenzae and S. pneumoniae, 48-86% in S. aureus, 37-69% in M. catarrhalis and 51-71% in E. coli. Mature biofilms were less susceptible to degradation. Moxifloxacin at concentrations that can be achieved in the bronchial mucosa during therapy therefore promotes a significant inhibition of biofilm synthesis and induces slime disruption, a feature that may be instrumental in reducing the exacerbations so frequently observed in this condition.     

Activity of daptomycin on biofilms produced on a plastic support by Staphylococcus spp

The aim of this study was to assess whether the novel lipopeptide daptomycin might be capable of disrupting or inhibiting the synthesis of biofilms produced by staphylococci. Fourteen recently isolated slime-producing methicillin-susceptible (MET-S) and methicillin-resistant (MET-R) strains (three MET-S Staphylococcus aureus, three MET-R S. aureus, three MET-S Staphylococcus epidermidis, three MET-R S. epidermidis and two vancomycin-intermediate S. aureus (VISA)) were tested. Slime formation on polystyrene plates was quantified spectrophotometrically. Daptomycin (2-64 mg/L) inhibited slime synthesis by > or =80% in MET-S strains, by 60-80% in MET-R S. aureus and by 70-95% in MET-R S. epidermidis. At 64 mg/L, biofilm synthesis decreased by 80% in the VISA isolates. Daptomycin also disrupted pre-formed biofilm: >50% breakdown of initial biofilm (5h) was observed in all strains. Disruption of mature biofilms (48 h), in terms of percentage, was more variable depending on the strain, ranging from ca. 20% in a MET-R S. epidermidis strain to almost 70% in two MET-S strains (one S. aureus and one S. epidermidis). Daptomycin at concentrations achievable during therapy promoted a statistically significant inhibition of slime synthesis (preventing biofilm building) and induced slime disruption (disaggregating its structure) both in initial and mature biofilms on a plastic support in all staphylococcal strains studied.     

Recombinant human DNase I decreases biofilm and increases antimicrobial susceptibility in staphylococci

Extracellular DNA is an adhesive component of staphylococcal biofilms. The aim of this study was to evaluate the antibiofilm activity of recombinant human DNase I (rhDNase) against Staphylococcus aureus and Staphylococcus epidermidis. Using a 96-well microtiter plate crystal-violet binding assay, we found that biofilm formation by S. aureus was efficiently inhibited by rhDNase at 1-4?μg?l?1, and preformed S. aureus biofilms were efficiently detached in 2?min by rhDNase at 1?mg?l?1. Pretreatment of S. aureus biofilms for 10?min with 10?mg?l?1 rhDNase increased their sensitivity to biocide killing by 4-5 log units. rhDNase at 10?mg?l?1 significantly inhibited biofilm formation by S. epidermidis in medium supplemented with sub-MICs of antibiotics. We also found that rhDNase significantly increased the survival of S. aureus-infected Caenorhabditis elegans nematodes treated with tobramycin compared with nematodes treated with tobramycin alone. We concluded that rhDNase exhibits potent antibiofilm and antimicrobial-sensitizing activities against S. aureus and S. epidermidis at clinically achievable concentrations. rhDNase, either alone or in combination with antimicrobial agents, may have applications in treating or preventing staphylococcal biofilm-related infections.     

Ability of Chitosan Gels to Disrupt Bacterial Biofilms and Their Applications in the Treatment of Bacterial Vaginosis

Recurrence of bacterial vaginosis is attributed to the inability of various formulations to disrupt bacterial biofilms. A negatively charged polysaccharide matrix coats the bacterial communities in the biofilm and restricts the penetration of antibiotics. Therefore, bacteria in the deeper segments of the biofilm persist and perpetuate the infection. In this study, we have tested the efficacy of two bioadhesive polymers, cationic chitosan and anionic polycarbophil, to disrupt Pseudomonas aeruginosa biofilms grown in the Center for Disease Control bioreactor as well as on the 96-well plates. The biofilms were treated with various concentrations of polycarbophil and chitosan at pH 4 or 6. Biofilm integrity following various treatments was evaluated by crystal violet stain and laser confocal microscopy employing Syto9 (live-cell stain) and propidium iodide (dead-cell stain). These studies demonstrated that chitosan gel disrupts the P. aeruginosa biofilm more effectively than does polycarbophil; and this effect is independent of the pH and charge densities on either polymers. © 2013 U.S. Government. 102:2096–2101, 2013     

Synergistic antimicrobial effect against early biofilm formation: micropatterned surface plus antibiotic treatment

The detrimental effects of biofilms are a cause of great concern in medical, industrial and environmental areas. In this study, we proposed a novel eradication strategy consisting of the combined use of micropatterned surfaces and antibiotics on biofilms to reduce the rate of bacterial colonisation. Pseudomonas fluorescens biofilms were used to perform a comparative evaluation of possible strategies to eradicate these biological layers. First, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration of planktonic cultures were determined. Subsequently, adhesion of bacteria on microstructured gold surfaces (MS) with patterned features that were similar to the bacterial diameter as well as on smooth nanostructured gold (NS) was assessed. As expected, lower bacterial attachment as well as inhibition of bacterial aggregation were observed on MS. The effect of streptomycin treatment (ST) in the concentration range 1-4mg/L (0.25-1× MIC) on biofilms grown on MS and NS was also evaluated. The combined strategy involving the use of micropatterned surfaces and antibiotic treatment (MS+ST) to eradicate Pseudomonas biofilms was then investigated. Results showed a synergistic effect of MS+ST that yielded a reduction of ≥1000-fold in the number of surviving biofilm bacteria with respect to those obtained with single ST or MS. The combined strategy may be a significant contribution to the eradication of biofilms from different environments. In addition, the important role of early monolayer bacterial aggregates in increasing resistance to antimicrobial agents was demonstrated.