耐亚胺培南鲍曼不动杆菌耐药机制研究

目的 研究鲍曼不动杆菌对亚胺培南的耐药机制。方法 对临床分离的3株耐亚胺培南的鲍曼不动杆菌，采用KB纸片扩散法（CLSI／NCCLS2004年标准）进行药敏试验，三维试验检测ESBLs和AmpC酶，PCR方法检测TEM、SHV、PER、VEB、AmpC、IMP、VIM、OXA-23和OXA-24等9种耐药基因型，PCR阳性产物进行基因测序，结果在GenBank基因库中比对分析。结果 3株鲍曼不动杆菌为多重耐药菌株，三维试验均产生ESBLs，1株产生AmpC酶，耐药基因型检测3株TEM阳性，2株PER阳性，2株AmpC酶阳性及SHV、VEB和IMP、VIM、OXA-24型等均为阴性；3株OXA-23型均阳性；另外27株对亚胺培南敏感鲍曼不动杆菌IMP、VIM，OXA-23和OXA-24型检测结果均阴性。结论 耐亚胺培南鲍曼不动杆菌携带TEM、PER、非诱导AmpC酶、OXA-23型碳青霉烯酶基因，产生OXA-23型碳青霉烯酶是主要耐药机制。     

某院2011年12月-2012年12月ICU亚胺培南耐药鲍曼不动杆菌碳青霉烯酶基因型的研究

目的:对重症监护病房(ICU)临床分离的亚胺培南耐药鲍曼不动杆菌的耐药性及碳青霉烯酶基因型进行研究,为临床防治提供理论依据。方法:收集2011年12月-2012年12月青岛市海慈医疗集团ICU临床分离的亚胺培南耐药鲍曼不动杆菌65株,采用K-B琼脂纸片扩散法进行药敏试验,聚合酶链反应(PCR)检测OXA-23、OXA-24、OXA-51、OXA-58、IMP、VIM 6种碳青霉烯酶基因,并对PCR产物进行测序。结果:65株亚胺培南耐药鲍曼不动杆菌除对头孢哌酮/舒巴坦、阿米卡星、多黏菌素B的耐药率较低外,对其他药物的耐药率均在90%以上。65株扩增出OXA-51基因,56株扩增出OXA-23基因,6株扩增出VIM基因,检出率分别为100%、86.15%、9.23%,OXA-24、OXA-58及IMP均未检出;PCR产物测序表明与GenBank相关基因同源性为100%。结论:该单位ICU亚胺培南耐药鲍曼不动杆菌的耐药现象严重;OXA-23型碳青霉烯酶的产生是鲍曼不动杆菌对碳青霉烯类药物耐药的重要机制之一。     

鲍曼不动杆菌OXA-23型碳青霉烯酶基因的研究

目的分析鲍曼不动杆菌的耐药性及其产OXA-23型碳青霉烯酶基因的核苷酸序列。方法用自动微生物分析仪测定常用抗菌药的MIC50；对OXA-23型碳青霉烯酶基因进行PCR扩增，产物纯化测序。结果15株产ESBLs鲍曼不动杆菌中有12株携带OXA-23型碳青霉烯酶；PCR产物纯化后测序表明与鲍曼不动杆菌（AY795964．1）blaxxA-23基因序列100％同源。结论携带OXA-23型碳青霉烯酶基因的鲍曼不动杆菌对临床常用抗菌药的耐药率高，其编码基因为blaoxA-23。     

鲍曼不动杆菌耐药性及碳青霉烯酶的研究

目的了解鲍曼不动杆菌耐药谱及碳青霉烯酶的研究。方法用VITEK60型全自动药敏分析系统鉴定药敏系统及纸片扩散法进行药敏实验;PCR扩增和测序分析检测碳青霉烯酶VIM、IMP、OXA-23和OXA-24。结果217株鲍曼不动杆菌中头孢哌酮/舒巴坦耐药率最低,其次是亚胺培南,再者是头孢他啶和哌拉西林/他唑巴坦;头孢哌酮/舒巴坦和头孢他啶的中介率分别是27.6%和19.8%;20株亚胺培南耐药菌中,PCR扩增VIM、IMP和OXA-24均阴性;OXA-23基因扩增显示19株（95%）阳性,PCR产物并经序列分析证实为OXA-23。结论碳青霉烯类抗生素的长期广泛应用使鲍曼不动杆菌的耐药率不断升高;产OXA-23型β-内酰胺酶是本院鲍曼不动杆菌对亚胺培南耐药的重要原因。     

耐碳青霉烯酶鲍曼不动杆菌分子流行病学调查

目的对耐碳青霉烯酶鲍曼不动杆菌之间的同源性进行分子流行病学调查，为防控院内感染提供依据。方法收集河南省人民医院重症监护病房2007年1—12月分离到的21株亚胺培南耐药鲍曼不动杆菌进行鉴定。用E-test法测定10种抗菌药物的最低抑菌浓度（MIC），脉冲场凝胶电泳（PFGE）分析其耐药株的同源性，对碳青霉烯类基因OXA-23型、OXA-24型、IMP型、VIM型基因进行PCR扩增及序列分析。结果14株鲍曼不动杆菌菌株为同一耐药克隆株，并检出OXA-23型碳青霉烯酶，21株鲍曼不动杆菌菌株均未检出OXA-24、IMP、VIM基因型。结论该院相同耐药克隆株在重症监护病房不同患者身上流行，可能与行气管插管、呼吸机、氧气湿化瓶、护士手操作有关。     

多重耐药不动杆菌碳青霉烯酶耐药基因及Ⅰ类整合子

了解安徽省多重耐药不动杆菌碳青霉烯类耐药的机制.方法 收集安徽省多家医院2006～2007年临床分离非重复的不动杆菌共167株,用琼脂稀释法测定最低抑菌浓度(MICs),用聚合酶链反应(PCR)扩增和克隆测序方法确认碳青霉烯酶基因,用PCR扩增整合酶.结果 34株对包括碳青霉烯类抗菌素在内的多种抗菌药耐药,34株中19株产OXA-23型碳青霉烯酶基因、23株Ⅰ类整合酶阳性,未检测到OXA-24型酶,IMP、VIM、SIM型金属酶基因和Ⅱ,Ⅲ整合酶基因.发现2株新基因取得登录号FJ194460;FJl94494.23株Ⅰ整合酶阳性菌株有21株测出Ⅰ类整合子基因结构.结论 安徽省多重耐药不动杆菌的耐药性与其携带OXA-23型酶和Ⅰ类整合子有关.     

耐亚胺培南鲍曼不动杆菌耐药性及OXA碳青霉烯酶检测

目的 分析97株临床分离的耐亚胺培南鲍曼不动杆菌的耐药特点及OxA碳青霉烯酶分布.方法 用国际标准平皿二倍稀释法,明确研究菌株的耐药表型;用脉冲场凝胶电泳法,对其进行分型并用PCR的方法,检测OXA碳青霉烯酶.结果 97株耐亚胺培南鲍曼不动杆菌均为多药耐药菌株,其中2株为泛耐药菌株;主要存在7个流行克隆株;有78株菌携带bal-oxa-23基因(80.4%);2株菌携带bal-oxa-58基因(2.1%);未发现携带bal-oxa-24基因的菌株.结论 在我国的亚胺培南耐药的鲍曼不动杆菌中,OXA-23仍为主要分布的碳青霉烯酶.     

重症监护病房耐碳青霉烯酶鲍曼不动杆菌分子流行病学调查

目的 对重症监护病房耐碳青霉烯酶鲍曼不动杆菌之间的同源性进行分子流行病学调查,为制定预防和控制其院内感染提供依据.方法 收集重症监护病房2007年1月至12月分离到的21株亚胺培南耐药鲍曼不动杆菌.采用全自动微生物分析系统PHOENIX 100对其进行鉴定,脉冲场凝胶电泳(PFGE)分析其耐药株的同源性,对碳青霉烯类基因OXA-23型、OXA-24型、IMP型、VIM型基因进行PCR扩增及序列分析.结果 14株鲍曼不动杆菌菌株为同一耐药克隆株,并检出OXA-23型碳青霉烯酶,21株鲍曼不动杆菌菌株均未检出OXA-24、IMP、VIM基因型.结论 相同耐药克隆株在重症监护病房不同患者身上流行,可能与行气管插管、呼吸机、氧气湿化瓶、护士手工操作有关.     

鲍曼不动杆菌及其耐药基因的检测

目的：探索一种检测鲍曼不动杆菌及其耐药基因的新方法。方法首先对近几年医院内鲍曼不动杆菌的耐药情况进行分析,选择临床上治疗鲍曼不动杆菌的首选药,再采用聚合酶链反应对鲍曼不动杆菌及其突变株进行检测。结果鲍曼不动杆菌对亚胺培南的耐药率最低,为9.37%,OXA-51基因扩增结果与细菌培养相符,OXA-23基因扩增与鲍曼不动杆菌耐亚胺培南的结果相符。结论采用PCR法对OXA-51基因扩增可以检测是否存在鲍曼不动杆菌,采用PCR法对OXA-23基因扩增可以检测鲍曼不动杆菌是否存在亚胺培南耐药性。从而快速检测鲍曼不动杆菌及其耐药基因,指导临床用药。     

鲍曼不动杆菌及其耐药基因的检测

目的探索一种检测鲍曼不动杆菌及其耐药基因的新方法。方法首先对近几年医院内鲍曼不动杆菌的耐药情况进行分析,选择临床上治疗鲍曼不动杆菌的首选药,再采用聚合酶链反应对鲍曼不动杆菌及其突变株进行检测。结果鲍曼不动杆菌对亚胺培南的耐药率最低,为9.37%,OXA-51基因扩增结果与细菌培养相符,OXA-23基因扩增与鲍曼不动杆菌耐亚胺培南的结果相符。结论采用PCR法对OXA-51基因扩增可以检测是否存在鲍曼不动杆菌,采用PCR法对OXA-23基因扩增可以检测鲍曼不动杆菌是否存在亚胺培南耐药性。从而快速检测鲍曼不动杆菌及其耐药基因,指导临床用药。     

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.