MRSA菌20株耐药性及耐药基因研究

目的对MRSA菌耐药性及耐药基因进行研究。方法对20株MRSA菌的耐药性和β内酰胺类耐药相关基因(mecA、TEM)、氨基糖甙类耐药相关基因（aac(6’)／aph(2”)、aph(3’)-Ⅲ、ant(3”)-Ⅰ、ant(2”)-Ⅰ、ant(6)-Ⅰ）、四环素耐药相关基因(tetM)等主要耐药基因进行检测。结果20株MRSA药敏试验除万古霉素、替考拉宁敏感外，青霉素、苯唑西林、头孢唑林、头孢呋辛、亚胺培南、庆大霉素、四环素、红霉素、环丙沙星等均耐药。20株MRSA菌均检出mecA、TEM、aac(6’)／aph(2”)、tetM等β内酰胺类、氨基糖甙类、四环素类、红霉素类耐药相关基因，其中6株还同时检出aph(3’)-Ⅲ基因。结论全部菌株均已携带β内酰胺类、氨基糖甙类、四环素类耐药相关基因。     

一株沃氏葡萄球菌耐药基因的研究

目的:研究沃氏葡萄球菌多重耐药情况和相关机制。方法:采用聚合酶链反应(PCR)法对一株多重耐药沃氏葡萄球菌进行β-内酰胺酶基因、氨基糖苷类修饰酶基因、大环内酯-林可酰胺-链阳菌素B类(MLSB)基因、四环素类基因、糖肽类基因、消毒剂基因检测。结果:PCR结果显示该株的mecA,TEM,ermA,ermC,msrA,msrB,aac(6′)/aph(2″),qacA基因均为阳性,ant(4′,4″),aph(3′)-,TetM,vanA,vanB基因均为阴性。结论:该株沃氏葡萄球菌存在多重耐药基因,而且对胺类、胍类消毒剂耐受。     

万古霉素敏感性减低葡萄球菌筛选及抗生素耐药相关基因检测

目的 了解万古霉素敏感性减低葡萄球菌临床分离株对-内酰胺类、氨基糖苷类、四环素以及万古霉素耐药相关基因存在状况.方法 采用含61tg/mL万古霉素脑心浸液琼脂从临床分离的葡萄球菌中筛选万古霉素中介葡萄球菌和万古霉素耐药葡萄球菌;采用菌谱分析法筛选异质性万古霉素耐药葡萄球菌:E-test法和琼脂稀释法检测其MIC值;PCR技术扩增mecA,aac(6')/aph(2'),aph(3)-Ⅲ,tetM,vanA.vanB和vanC基因,并对阳性扩增产物进行测序.结果 从100株临床分离葡萄球菌中检出7株异质性万古霉素耐药葡萄球菌,并从部分菌株中检出耐药基因,mecA,aac(6')/aph(2'),aph(3')-川基因检出率分别为85.7%,57.1%和85.7%,没有检出tetM,vanA,vanB和vanC.对PCR阳性扩增产物进行测序,BLASTn比对分析,与已登录基因库的相同基因序列具有高度同源性.结论 同甲氧西林耐药葡萄球菌相似,万古霉素敏感性减低葡萄球菌携带多种耐药基因,耐药表型与基因分析支持该菌株多药耐药,该类菌株的检测对于指导临床合理用药具有积极意义.     

金黄色葡萄球菌耐药性及耐药基因检测

目的 检测金黄色葡萄球菌对临床常用抗生素的耐药性和相关耐药基因.方法 收集2005年至2006年分离自河北医科大学第四医院临床患者的金黄色葡萄球菌74株,微量肉汤稀释法检测上述细菌抗生素的敏感性;硝噻吩(Nitrocefin)纸片法检测β-内酰胺酶产生情况;微量肉汤稀释法和头孢西丁纸片法检测甲氧西林耐药的金黄色葡萄球菌(MRSA);聚合酶链式反应(PCR)对该74株受试菌β-内酰胺类抗生素的耐药基因TEM;甲氧西林耐药基因mecA;氨基糖苷类修饰酶aac(6’)/aph(2')、aph(3’)、ant(4’,4');四环素类耐药相关基因tetM.结果 74株金黄色葡萄球菌对青霉素、氨苄青霉素98.64％耐药;73株金黄色葡萄球菌β-内酰胺酶阳性,产酶率为98.6％ (73/74),TEM基因检出率为98.6％ (73/74).对头孢唑啉、头孢噻吩、头孢噻肟耐药率高达70.27％;MRSA检出率为63.5％ (47/74),47株MRSA的mecA基因进行检测,检出率为87.2％ (41/47).对庆大霉素耐药率为74.32％;aac(6’)/aph(2')、aph (3’)、ant(4’,4')检出率分别为63.5％ (47/74)、18.92％ (14/74)、4.05％ (3/74);47株MRSA中检出率分别为83.0％ (39/47)、23.4％ (11/47)、4.26％( 2/47),MSSA中检出率为29.6％ (8/27)、11.1％ (3/11)、3.7％ (1/27).对四环素耐药率为74.32％;tetM基因检出率为73.0％( 54/74);MRSA株中检出率为97.9％ (46/47),MSSA株中检出率为29.6％ (8/27).结论 目前临床感染的金黄色葡萄球菌呈多重耐药菌,尤其是MRSA多重耐药严重,耐药基因检测与临床药敏实验结果相符.     

耐甲氧西林金葡菌对抗菌药物的耐药表型和基因型分析

目的 了解来自汕头和北京地区的67株耐甲氧西林金葡菌(MRSA)的耐药情况及耐药机制,并分析耐药表型与基因型的一致情况.方法 以琼脂稀释法测定24种抗菌药物对MRSA的体外抗菌活性,PCR扩增MRSA的耐药基因,nitrocefin测定细菌产β-内酰胺酶的情况.结果 67株MRSA除了对氯霉素和多西环素的耐药率较低,分别为3%和7.5%,对万古霉素、米诺环素和利凡诺100%敏感外,对利福平的耐药率为52.2%,对四环素的耐药率为77.6%,而对于其它包括青霉素、第1～4代头孢菌素、单环β-内酰胺类、碳青霉烯类、氨基糖苷类和磺胺类的耐药率均在80%～90%以上,氨苄西林加酶抑制剂以后则耐药程度有所降低.qacA/B、mecA、tetM、NorA、gyrA、aac(6')/aph(2")、aph(3')Ⅲ和β-内酰胺酶检出率分别为11.9%、95.5%、70.1%、4.5%、10.4%、82.1%、73.1%和92.5%,未检出qacC、ant(6)-I、ant(2")-I、VanA和VanB耐药基因.67株MRSA均携带有多种耐药基因:同时携带2种耐药基因的有7株,3种的有10K,4种的有11株,5种的29株,6种的10株.结论 67株MRSA耐药情况严重,并同时携带多种耐药基因.     

一株多重耐药铜绿假单胞菌耐药基因的研究

目的:研究铜绿假单胞菌多重耐药情况和相关机制。方法:采用聚合酶链式反应(PCR)法对一株多重耐药铜绿假单胞菌进行β-内酰胺酶基因、氨基糖苷类修饰酶基因、氯霉素类基因、耐消毒剂和磺胺类基因检测。结果:PCR结果显示该株PA的TEM,MIR,CTX-M1群,OXA-1群,OXA-10群,aac(6′)-b,aac(6′)-,aac(3)-,ant(2″)-,catB,qacE△1-sul1基因均为阳性,GES,DHA,VEB,cmlA基因均阴性,Opr D2未缺失。结论:该株铜绿假单胞菌存在多重耐药基因,而且对胺类、胍类消毒剂耐受。     

耐亚胺培南铜绿假单胞菌和嗜麦芽寡养单胞菌抗菌药物耐药基因研究

目的分析浙江省湖州解放军第98医院自临床分离的耐亚胺培南铜绿假单胞菌（IRPa）和嗜麦芽寡养单胞菌（Sm）中抗菌药物相关耐药基因存在状况。方法2003年9月至2004年10月间从临床分离28株IRPa和19株Sm，采用聚合酶链反应及序列分析的方法分析8种B一内酰胺酶基因（blaIMP、blaVIM、blaTEM、blaSHV、blaOXA、blaPER、blaVEB和blaGES）、9种氨基糖苷类修饰酶基因（AMEs基因）Eaac（3）-Ⅰ、aac（3）-Ⅱ、aac（3）-Ⅲ、aac（3）-Ⅳ、aac（6’）-Ⅰ、aac（6’）-Ⅱ、ant（3″）-Ⅰ、ant（2″）-Ⅰ和aph（3’）-Ⅵ]、外膜孔蛋白D2基因（oprD）、消毒剂-磺胺耐药相关基因（qacE△1-sul1）、氯霉素乙酰转移酶基因（catB）、氯霉素外排蛋白基因（cml1）。结果28株IRPa中bLatEM、blaOXA、aac（3）-Ⅱ、aac（6’）-Ⅱ、ant（3″）-Ⅰ、ant（2″）-Ⅰ和qacE△1-sul1基因的阳性株数（％）分别为20株（71．4％）、1株（3．6％）、23株（82．1％）、10株（35．7％）、15株（53．6％）、8株（28．6％）和24株（85．7％），AMEs基因总阳性率为89．3％，blaOXA基因经序列分析确认为blaOXA-10型超广谱β-内酰胺酶，25株（89．3％）发生oprD基因缺失突变。19株Sm中aac（6’）-Ⅱ、ant（2″）-Ⅰ及qacE△1-sul1基因的阳性株数（％）均为2株（10．5％）；其余基因均阴性。结论临床分离的IRPa中存在blaTEM、blaOXA-10、aac（3）-Ⅱ、aac（6’）-Ⅱ、ant（3″）-Ⅰ、ant（2″）-Ⅰ和qacE△1-sul1基因，oprD基因缺失突变率很高。Sm中存在aac（6’）-Ⅱ、ant（2″）-Ⅰ及qacE△1-sul1基因。     

雏鸭腹泻大肠埃希菌耐药性和氨基糖苷类抗生素耐药基因检测与分析

目的 研究雏鸭腹泻大肠埃希菌的耐药性和氨基糖苷类抗生素耐药基因的存在情况。方法 采取山东济宁某养鸭场腹泻雏鸭粪便病料，通过实验室分离培养，对雏鸭腹泻大肠埃希菌进行药敏试验，比较雏鸭腹泻大肠埃希菌分离株对抗菌药物的敏感性，并采用PCR法对氨基糖苷类抗生素耐药菌株进行氨基糖苷类抗生素耐药基因aac(3)-Ⅰ、aac(3)-Ⅱ、aac(6’)-Ⅰb、aac(6’)-Ⅱ、ant(3”)-Ⅰ和aph(3’)-Ⅱ的检测。结果 在24种药物敏感性试验中，雏鸭腹泻大肠埃希菌对头孢他啶、头孢哌酮、头孢吡肟和阿米卡星4种药物敏感，对氧氟沙星、头孢曲松、头孢噻肟和大观霉素4种药物中度敏感；对青霉素、链霉素、庆大霉素和四环素等16种药物耐药。在20株菌株中，检测的氨基糖苷类抗生素耐药基因中5株细菌检测出aac(3)-Ⅰ，10株细菌检测出aac(3)-Ⅱ，5株细菌检测出aac(6’)-Ⅰb,6株细菌检测出aac(6’)-Ⅱ，8株细菌检测出ant(3”)-Ⅰ，17株细菌检测出aph(3’)-Ⅱ。结论此次试验分离培养出的雏鸭腹泻大肠埃希菌呈现普遍耐药性，普遍检测出氨基糖苷类抗生素耐药基因aac(3)-Ⅰ、aac(3...     

铜绿假单胞菌“泛耐株”耐药相关基因研究

目的 研究"泛耐"铜绿假单胞菌中多种耐药基因的存在情况及耐药机制.方法 采用聚合酶链反应(PCR)法检测22株"泛耐"铜绿假单胞菌的β-内酰胺酶基因、氨基糖苷类修饰酶(AMEs)基因、喹诺酮类耐药基因、耐消毒剂基因(qacE△l-sull)和整合酶基因.结果 PCR扩增结果显示22株菌中oprD2、blaCAEB、gyrA、aac(6')-Ⅰb、ant(2")-Ⅰ和qacE △ J-sull基因均阳性;blaSHV、blaSPM、blaGIM、blaDHA、blaOXA-10、blaGES、blaPER、aac(3')-Ⅰ和aac(6')-Ⅱ基因均阴性;blaIMP、blaTEM、blaVEB、aac(3')-Ⅱ、ant(3")-Ⅰ、int Ⅰ1和blaVIM阳性率分别为95.5%、77.3%、13.6%、4.5%、4.5%、4.5%和4.5%.结论 oprD2基因阳性说明这些泛耐菌株中外膜蛋白并未缺失,多种耐药基因同时存在是本研究中铜绿假单胞菌"泛耐"的根本原因.     

多重耐药淋病奈瑟菌耐药基因的研究

目的探讨多重耐药淋病奈瑟菌的耐药基因。方法应用KB法与琼脂稀释法测定35株淋病奈瑟菌对抗生素的敏感性，煮沸法提取菌株DNA，PCR扩增blaTEM基因、tetM基因、erm基因和mefA基因。结果35株淋病奈瑟菌的敏感性测定结果显示多重耐药；blaTEM耐药基因的检出率为88．6％，tetM基因的携带率为11．4％，首次在国内从35株淋病奈瑟菌中检出reef、erm耐药基因，其中2株mefA基因阳性，1株erm基因阳性。结论淋病奈瑟菌的多重耐药与各耐药基因型之间密切相关。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.