柠檬提取物对耐药金黄色葡萄球菌抑菌作用机理的研究

目的观察柠檬提取物对多重耐药金黄色葡萄球菌的抑菌效果及其抑菌作用机理。方法采用纸片法和稀释法进行抑菌试验;采用电泳法和生化检验法观察抑菌作用机理。结果柠檬提取物原液对临床分离的耐药金黄色葡萄球菌的纸片抑菌实验抑菌环>30 mm,最小抑菌浓度为柠檬提取物1∶6400稀释度。在不同浓度凝胶电泳图谱中,耐药金黄色葡萄球菌经柠檬提取物作用后发生较明显变化的蛋白质条带共有5条,说明有明显的菌体蛋白电泳图谱的改变;没有观察到柠檬提取物作用后细菌酶活性的改变。结论柠檬提取物对耐药金黄色葡萄球菌有明显的抑制作用,该提取物作用后的耐药金黄色葡萄球菌菌体蛋白合成量有明显改变。     

氯己定对4株温和气单胞菌的抑制与杀灭作用

采用对倍稀释系列浓度定性试验法 ,测定醋酸氯己定对不同来源的 4株温和气单胞菌的最小抑菌浓度和最小杀菌浓度。结果 ,北京从临床标本分离的 3株与沈阳临床分离株对氯己定的抗力无明显差别。氯己定对它们的最小抑菌浓度与最小杀菌浓度分别为 13 6mg/L与 2 7 2mg/L。     

两种浓度氯已定皮肤消毒剂持续抑菌效果观察

目的观察2种浓度葡萄糖酸盐氯己定的皮肤抑菌效果。方法根据英国测试和材料协会(ASTM)相关测试方法,对受试者在用氯己定皮肤消毒前和消毒后不同时间段分别进行采样培养,检测消毒效果。结果消毒前菌数平均对数值大于2.65 lg cfu/ml,2种不同浓度氯已定消毒即时的杀菌率都在99%以上,此后出现细菌反弹,5 g/L氯已定消毒液皮肤持续抑菌时间在48 h左右,此后细菌明显反弹,96 h已恢复消毒前水平。20 g/L氯已定消毒皮肤持续抑菌时间可持续在192 h,仅为消毒前菌数水平的0.5%,显示良好的长效抑菌性能。结论 2种浓度氯己定经ASTM方法检测氯已定皮肤消毒后在皮肤上有明显的残留抑菌活性。     

多重耐药鲍曼不动杆菌对氯己定醇手消毒剂的抗性研究

摘要 目的 研究多重耐药鲍曼不动杆菌对氯己定醇手消毒剂的抗性变化,为科学实施医院消毒提供依据。方法 采用最小抑菌浓度测试方法,检测2种氯己定醇消毒剂对临床分离多重耐药鲍曼不动杆菌最小抑菌浓度(MIC),分析其抗性变化。结果 A、B 2种消毒剂含醋酸氯己定分别为1 750.00 mg/L和5 000.00 mg/L,含乙醇均为体积分数67.3%。以醋酸氯己定标示MIC值,消毒剂A对临床分离鲍曼不动杆菌、大肠杆菌和铜绿假单胞菌标准株的MIC值依次为43.75 mg/L、17.50 mg/L和29.20 mg/L;消毒剂B对上述3种细菌的MIC值依次为125.00 mg/L、50.00 mg/L和83.30 mg/L。结论 临床分离多重耐药鲍曼不动杆菌对氯己定醇手消毒剂的耐受浓度明显高于大肠杆菌和铜绿假单胞菌标准菌株,提示其抗力有增强趋势。     

冻干猪皮抑菌及渗透消毒剂作用的实验研究

目的解决大面积烧伤病人手术用皮,对冷冻猪皮进行消毒处理并观察其抑菌作用。方法用消毒液浸泡处理和改良kirby-bauer法(抑菌环试验方法)进行了观察。结果冻干猪皮显示出明显抑菌作用,在冻干猪皮中心贴上含氯己定的滤纸片可明显提高猪皮的抑菌效果;用醋酸氯己定溶液浸泡的冻干猪皮抑菌效果最好。进行多个均数间的两两比较,证明冻干皮组与贴滤纸片组,冻干皮组与氯己定浸泡皮组,贴滤纸片组与氯己定浸泡皮组之间抑菌环的平均数差异显著。冻干皮片组和贴氯己定滤纸片组对铜绿假单胞菌均无抑菌作用;浸有消毒液的冻干皮片组只有6/20平板上显示出对铜绿假单胞菌有比较弱的抑菌作用;氯己定滤纸片对照组只有17/20平板上显示出8~10 mm的抑菌环。结论新鲜猪皮片经醋酸氯己定溶液消毒处理,冻干后本身具有一定的抑菌作用,但其作用有限;冻干皮片经500 mg/L醋酸氯己定浸泡处理,可明显提高其抑菌作用。     

壳聚糖温敏凝胶共混环糊精缓释氯己定的体外实验

目的:探索壳聚糖温敏凝胶缓释广谱抗菌药物氯己定的解决办法。方法:实验于2006-03/06在解放军第四军医大学化学实验室进行。将小分子药物氯己定先通过饱和水溶液法与β-环糊精制备成包结物,再共混于壳聚糖温敏凝胶中,制备载药凝胶系统。根据不同配方分为4组:空白凝胶组:壳聚糖温敏凝胶溶液;β-环糊精/氯己定包结物6mg或12mg组:壳聚糖温敏凝胶溶液 6mg或12mgβ-环糊精/氯己定包结物;氯己定组:壳聚糖温敏凝胶溶液 4.8mg氯己定。检测最终的凝胶体系的流变学性质、稳定性、体外释药特性。结果:①氯己定与β-环糊精的包合率为(40.11±4.28)%。②流变学检测显示,β-环糊精/氯己定包结物6mg或12mg组凝胶黏度随温度升高而略有升高,但其变化趋势与空白凝胶组无差异;恒温37℃条件下,此2组凝胶黏度随时间波动性变化,但其变化趋势与空白凝胶组无差异。③稳定性检测结果:37℃条件下,无论是否加载药物,溶液都在8min左右形成稳定的凝胶,凝胶外观在1个月内无明显变化。④体外释放测定结果:实验条件下,氯己定组大约12h即释放完毕,而β-环糊精/氯己定包结物6mg组在40d时,仅释放药物的60%左右。结论:氯己定共混于壳聚糖温敏凝胶后,温敏凝胶系统的性质几乎未受加入药物的影响,而氯己定从凝胶系统中释放的速度大大减慢,药物持续释放可保持1个月以上,达到了缓释的目的。     

四种标准菌株对两种氯己定类消毒剂的抗力研究

目的了解4种试验标准菌株对醋酸氯己定和葡萄糖酸氯己定的抗力。方法采用肉汤稀释法测定醋酸氯己定和葡萄糖酸氯己定对各试验菌的最小抑菌浓度和最小杀菌浓度。结果醋酸氯己定对金黄色葡萄球菌、大肠杆菌、白色念珠菌和铜绿假单胞菌的最小抑菌浓度分别为2、2、8和40 mg/L;最小杀菌浓度分别为512、1024、1024和1024 mg/L。葡萄糖酸氯己定对上述菌株的最小抑菌浓度分别为4、4、16和80 mg/L;最小杀菌浓度分别为1024、1024、2048和4096 mg/L。结论这两种消毒剂对4种试验标准菌株的最小杀菌浓度明显高于最小抑菌浓度。     

不同浓度氯己定口腔护理液对机械通气病人抑菌效果及呼吸机相关性肺炎防治效果研究

[目的]探讨不同浓度氯己定口腔护理液对机械通气病人的抑菌效果以及呼吸机相关性肺炎(VAP)的防治效果。[方法]采用随机数字表法将120例机械通气治疗病人随机分为3组各40例,对照组采用生理盐水进行口腔护理,低浓度氯己定组应用0.12%的氯己定进行口腔护理,高浓度氯己定组应用2%氯己定进行口腔护理。7d后比较口腔护理效果,记录3组受试者VAP发生情况、机械通气时间、入住ICU时间、住院时间以及死亡情况并进行比较。[结果]干预7d后,3组受试者细菌阳性率、菌落数、牙菌斑指数、VAP发生率、机械通气时间、入住ICU时间、住院时间比较差异均有统计学意义(P0.05)。[结论]机械通气病人口腔护理中应用氯己定溶液有利于提高抑菌效果,缩短住院时间,降低VAP发生率,且0.12%浓度的氯己定溶液效果更优。     

两种皮肤消毒剂对四种多重耐药菌消毒效果的研究

目的检测安尔碘和葡萄糖酸氯己定皮肤消毒剂对于多重耐药菌的消毒效果。方法筛选耐甲氧西林金黄色葡萄球菌(MRSA)、耐万古霉素肠球菌(VRE)、耐碳青霉烯肺炎克雷伯菌(KPC)和多重耐药鲍曼不动杆菌(MDRAB)临床分离株,利用抑菌环试验测定2种消毒剂对多重耐药菌的最小抑菌浓度(MIC)。结果安尔碘皮肤消毒剂对于MRSA、VRE、KPC和MDRAB的MIC值分别为31.25 mg/L、125.00 mg/L、250.00和500.00 mg/L。2%葡萄糖酸氯己定皮肤消毒液对于MRSA、VRE、KPC和MDRAB的MIC值分别为19.53 mg/L、39.06 mg/L、312.50 mg/L和625.00 mg/L。结论此2种皮肤消毒剂对于多重耐药菌消毒效果良好,但推荐使用浓度与耐药菌MIC值存在差异,应加强对常用消毒剂的监测,及时调整消毒剂使用种类和浓度,减少病原菌对消毒剂耐药性的发生。     

葡萄糖酸氯己定与碘伏联合使用的相容性研究

目的研究葡萄糖酸氯己定与聚维酮碘联合使用的相容性及其抑菌效果。方法采用棋盘式稀释法,通过杀菌浓度指数来判断葡萄糖酸氯己定和碘伏的相互作用。结果单独葡萄糖酸氯己定对大肠杆菌和金黄色葡萄球的最小抑菌浓度为0.36 mg/L,对铜绿假单胞杆菌和白色念珠菌的最小抑菌浓度分别为2.9 mg/L和为0.75 mg/L。单独聚维酮碘对大肠杆菌、金黄色葡萄球菌、铜绿假单胞杆菌和白色念珠菌的最小抑菌浓度均为有效碘62.5 mg/L。葡萄糖酸氯己定与聚维酮碘联合使用对上述4种试验菌抑菌浓度指数均为2.0。结论葡萄糖酸氯己定与聚维酮碘联合使用对上述4种试验菌抑菌活性的强弱无关,既不增效,也不产生拮抗。     

Inhibition of Providencia stuartii cell envelope enzymes by chlorhexidine

The possibility that chlorhexidine is a specific inhibitor of membrane bound bacterial adenosine triphosphatase (ATPase) was addressed. The in-vitro susceptibilities of several Providencia stuartii cell envelope enzymes, including ATPase, to chlorhexidine were compared. The following concentrations of chlorhexidine were required to cause 50% inhibition of enzyme activity in preparations from chlorhexidine-sensitive strains (MIC 50 mg chlorhexidine/l): ATPase (160 mg/l), succinic dehydrogenase (greater than 300 mg/l), penicillin binding protein 7 (300 mg/l) and beta-lactamase (45 mg/l). Fifty per cent inhibition of the ATPase from a chlorhexidine-resistant strain (MIC 1600 mg/l) was achieved at an in-vitro concentration of 225 mg chlorhexidine/l. Our observations do not support the suggestion that bacterial membrane-bound ATPases are specific targets for chlorhexidine.     

Assessment of timed bacteriostatic and bactericidal activities of cephalothin against gram-positive and gram-negative bacteria

The comparative bacteriostatic and bactericidal activities of cephalothin were assessed in broth medium with special reference to the period of exposure of microbes to the drug. The bacteriostatic concentration with a brief period of exposure (6 h) was lower than the conventional MIC for Escherichia coli and Klebsiella sp. When the period of exposure was prolonged (18-42 h), the bacteriostatic concentration almost corresponded with the MIC. In contrast to these gram-negatives, the bacteriostatic concentration with a brief period of exposure roughly corresponded with the MIC for strains of Staphylococcus aureus and was higher for enterococcus. When a comparison of the bacteriostatic and the bactericidal concentrations was used as the criterion for assessment, the mode of action of cephalothin appeared to be bactericidal to most of the gram-negatives. This drug was bacteriostatic to a number of strains of gram-positives, in particular to enterococcus, especially when microbes were exposed to the drug over a brief period of time.     

Treatment of plastic and extracellular matrix components with chlorhexidine or benzalkonium chloride: effect on Candida albicans adherence capacity in vitro

This study investigates the influence of treatment of plastic and extracellular matrix (ECM) proteins with chlorhexidine or benzalkonium chloride on subsequent adherence of Candida albicans. Three concentrations were tested for each antiseptic: (i) chlorhexidine, MIC (6.25-12.5 mg/L), 80 x MIC and 800 x MIC; and (ii) benzalkonium chloride, MIC (3.12 mg/L), 40 x MIC and 1600 x MIC. Chlorhexidine and benzalkonium chloride activities were correlated with the tested concentrations. Antiseptics used at MIC were unable to modify the adherence to plastic or ECM proteins. Chlorhexidine (80 x MIC) induced a decrease in plastic adherence of 31% of the 15 strains used and an increase in ECM protein adherence of 13% of strains. Benzalkonium chloride (40 x MIC) induced a decrease in adherence to ECM proteins or plastic of 13-27% of strains. Our results indicated that the treatment with 1600 x MIC benzalkonium chloride could induce the opposite effect on adherence, depending on the surface: 60% of the strains showed an increase in their adherence to ECM proteins, whereas 93% of the strains showed a decrease in their adherence to plastic. A similar phenomenon was observed after treatment with 800 x MIC chlorhexidine: 60% of the strains showed an increase in their adherence to ECM proteins, whereas 67% showed a decrease in adherence to plastic. Treatment of medical devices with at least 5000 mg/L of chlorhexidine or benzalkonium chloride could therefore reduce C. albicans adherence to plastic surfaces, but would be unable to prevent fungal adherence to ECM proteins.     

无花果叶提取物抑菌作用的实验研究

为研究无花果叶乙醇提取液的体外抑菌作用,采用抑菌环试验和营养肉汤稀释法对其抑菌效果进行了试验观察。结果,含无花果叶生药100 mg/L的乙醇提取液对金黄色葡萄球菌、大肠杆菌、蜡状芽孢杆菌等8种细菌的抑菌环直径均大于7 mm。无花果提取物对金黄色葡萄球菌和枯草杆菌黑色变种的最低抑菌浓度(M IC)为12.5 mg/m l。结论,无花果叶提取物在体外具有明显的抑菌作用。     

Chlorhexidine Induces VanA-Type Vancomycin Resistance Genes in Enterococci

Chlorhexidine is a bisbiguanide antiseptic used for infection control. Vancomycin-resistant E. faecium (VREfm) is among the leading causes of hospital-acquired infections. VREfm may be exposed to chlorhexidine at supra- and subinhibitory concentrations as a result of chlorhexidine bathing and chlorhexidine-impregnated central venous catheter use. We used RNA sequencing to investigate how VREfm responds to chlorhexidine gluconate exposure. Among the 35 genes upregulated ≥10-fold after 15 min of exposure to the MIC of chlorhexidine gluconate were those encoding VanA-type vancomycin resistance (vanHAX) and those associated with reduced daptomycin susceptibility (liaXYZ). We confirmed that vanA upregulation was not strain or species specific by querying other VanA-type VRE. VanB-type genes were not induced. The vanH promoter was found to be responsive to subinhibitory chlorhexidine gluconate in VREfm, as was production of the VanX protein. Using vanH reporter experiments with Bacillus subtilis and deletion analysis in VREfm, we found that this phenomenon is VanR dependent. Deletion of vanR did not result in increased chlorhexidine susceptibility, demonstrating that vanHAX induction is not protective against chlorhexidine. As expected, VanA-type VRE is more susceptible to ceftriaxone in the presence of sub-MIC chlorhexidine. Unexpectedly, VREfm is also more susceptible to vancomycin in the presence of subinhibitory chlorhexidine, suggesting that chlorhexidine-induced gene expression changes lead to additional alterations in cell wall synthesis. We conclude that chlorhexidine induces expression of VanA-type vancomycin resistance genes and genes associated with daptomycin nonsusceptibility. Overall, our results indicate that the impacts of subinhibitory chlorhexidine exposure on hospital-associated pathogens should be further investigated in laboratory studies.     

钛表面单宁酸络合氯化钙涂层接枝氯己定功能及稳定性探究

目的 探究钛表面单宁酸和氯化钙络合后接枝氯己定的生物相容性、抗菌性以及稳定性.以期在种植体表面构建持久抗菌涂层.方法 商业钛片经打磨后,以光滑钛片为对照组,接枝不同浓度的氯己定.通过X射线光电子能谱分析元素组成.接触角测量仪分析其亲水性,Zeta电位实验分析其反应稳定性,金黄色葡萄球菌的涂板计数法,抑菌环法以及增值法分...     

氮酮抑菌机理的研究

经检测，细菌经氮酮作用后，对受抑制作用的金黄色葡萄球菌与枯草杆菌，菌体内多种酶大量外漏，对不受抑制作用的大肠杆菌则无此现象。扫描电镜下看到，受抑制菌体结构破坏，从而表明抑制作用主要因菌体外壁破坏，体内酶外漏所致。     

Transient and Sustained Bacterial Adaptation following Repeated Sublethal Exposure to Microbicides and a Novel Human Antimicrobial Peptide

Microbicides (biocides) play an important role in the prevention and treatment of infections. While there is currently little evidence for in-use treatment failures attributable to acquired reductions in microbicide susceptibility, the susceptibility of some bacteria can be reduced by sublethal laboratory exposure to certain agents. In this investigation, a range of environmental bacterial isolates (11 genera, 18 species) were repeatedly exposed to four microbicides (cetrimide, chlorhexidine, polyhexamethylene biguanide [PHMB], and triclosan) and a cationic apolipoprotein E-derived antimicrobial peptide (apoEdpL-W) using a previously validated exposure system. Susceptibilities (MICs and minimum bactericidal concentrations [MBCs]) were determined before and after 10 passages (P10) in the presence of an antimicrobial and then after a further 10 passages without an antimicrobial to determine the stability of any adaptations. Bacteria exhibiting >4-fold increases in MBCs were further examined for alterations in biofilm-forming ability. Following microbicide exposure, ≥4-fold decreases in susceptibility (MIC or MBC) occurred for cetrimide (5/18 bacteria), apoEdpL-W (7/18), chlorhexidine (8/18), PHMB (8/18), and triclosan (11/18). Of the 34 ≥4-fold increases in the MICs, 15 were fully reversible, 13 were partially reversible, and 6 were nonreversible. Of the 26 ≥4-fold increases in the MBCs, 7 were fully reversible, 14 were partially reversible, and 5 were nonreversible. Significant decreases in biofilm formation in P10 strains occurred for apoEdpL-W (1/18 bacteria), chlorhexidine (1/18), and triclosan (2/18), while significant increases occurred for apoEdpL-W (1/18), triclosan (1/18), and chlorhexidine (2/18). These data indicate that the stability of induced changes in microbicide susceptibility varies but may be sustained for some combinations of a bacterium and a microbicide.     

三种复方醋酸氯己定洗液抑菌效果的比较

目的比较三种醋酸氯己定洗液抑菌效果,为实际应用提供参考。方法采用定量抑菌试验方法,对此三种醋酸氯己定洗液抑菌效果进行了检测。结果三种复方醋酸氯己定中药洗液的原液作用2 min,大肠杆菌和金黄色葡萄球菌抑菌率均为100%;金鸡洗液和康洁阴洗液对白色念珠菌抑菌率达到100%,分别需要作用2 min和5min;日清康洗液对白色念珠菌作用20 min,抑菌率只有81.77%。结论三种复方醋酸氯己定中药洗液对细菌繁殖体具有良好的抑菌效果,但日清康洗液对白色念珠菌抑菌作用较低。     

Antagonistic effect of penicillin-amikacin combinations against enterococci.

Amikacin has been shown to antagonize the bactericidal effect of penicillin against strains of Streptococcus faecalis which produce aminoglycoside 3'-phosphotransferase. The mechanism by which this phenomenon occurs was studied with an enzyme-producing strain (8436) and an enzyme-negative strain (8436c) derived by curing the former with novobiocin. Combinations of amikacin with beta-lactam antibiotics were antagonistic against strain 8436 but synergistic against strain 8436c. Against strain 8436 penicillin-amikacin combinations resulted in levels of killing comparable to those seen with high concentrations of penicillin (500 micrograms/ml), which were less bactericidal than lower concentrations of penicillin. No antagonism was observed between amikacin and non-beta-lactam cell wall-active drugs or between penicillin and kanamycin or neomycin, both of which are substrates for the enzyme. At concentrations near the MIC, amikacin was bactericidal against strain 8436c but bacteriostatic against strain 8436 (MIC, 250 micrograms/ml; MBC, 2,000 micrograms/ml). Neither penicillin nor phosphorylated amikacin affected the inhibition of ribosomal protein synthesis by amikacin in a cell-free system. Although antagonism of killing by amikacin in enzyme-positive strains was specific for combinations which included beta-lactam antibiotics, amikacin did not influence the binding of [3H]penicillin to penicillin-binding proteins in isolated bacterial cell membranes or in intact cells and did not detectably affect the autolytic system of cells exposed to penicillin. Antagonism of beta-lactam activity by a bacteriostatic effect of amikacin against the enzyme-producing strain is the most likely explanation for this phenomenon.