生牛奶中分离大肠杆菌对季铵盐类消毒剂耐药性研究

目的为调查牛奶中大肠杆菌Escherichia coli的污染状况和对常见季铵盐类消毒剂的耐药情况,为大型养殖场季铵盐类消毒剂的合理使用提供指导。方法对从74份生牛奶样品中分离的45株大肠杆菌采用琼脂稀释法测定4种季铵盐类消毒剂[十六烷基三甲基溴化铵(CTAB)、苯扎氯铵(BC)、双十烷基二甲基氯化铵(DDAC)、氯代十六烷基吡啶(CPC)]的最小抑菌浓度(MIC),采用PCR法检测10种消毒剂耐药基因,并分析其MIC值与耐药基因之间的相关性。结果大肠杆菌对4种消毒剂表现出不同程度的抗性,所检测的4种消毒剂对大肠杆菌的MIC值均大于标准菌株,且比例为BC=DDACCTABCPC。大肠杆菌季铵盐类消毒剂的耐药基因检出率为ydgF(84.44%)ydgE(80.00%)sugE(c)(66.67%)emrE(40.00%)mdfA(37.78%)qacEΔ1(33.33%)qacE(17.78%)qacF(13.33%)qacG(11.11%)sugE(p)(4.44%)。分析大肠杆菌消毒剂基因检出情况与MIC值之间的关系发现,qacF基因的检出率与128 mg·L~(-1)的CPC之间差异有统计学意义。结论由此可见,牛奶中存在大肠杆菌污染严重的现象对季铵盐类消毒剂耐药情况不容乐观,需进一步规范季铵盐类消毒剂的使用。     

沙门氏菌对季铵盐类消毒剂的适应性耐受机制研究进展

沙门氏菌（Salmonella）是一种极其重要的食源性致病菌,具有耐高温、抗逆性强的特点,能在食品加工环境中长久存活。季铵盐类消毒剂在食品工业中的广泛应用使得沙门氏菌对其产生了适应性耐受和交叉耐受,为食品健康带来了极大的安全隐患。文章简要介绍了季铵盐类消毒剂的主要种类及其作用机理,分析并归纳了沙门氏菌对季铵盐类消毒剂的适应性耐受和交叉耐受现状,进一步从细胞膜生理特征、生物被膜形成、外排泵活性等角度,重点阐述了沙门氏菌对季铵盐类消毒剂的适应性耐受机制进展及新发现,并对未来研究方向进行了展望,旨在为季铵盐类消毒剂的合理使用和沙门氏菌的防控提供重要参考。     

食源微生物对季铵盐类消毒剂的抗性

季铵盐类消毒剂基于其高效低毒的杀菌效果,在食品加工、畜牧养殖、公共场所消毒各个方面得到广泛的应用,但是滥用消毒剂会使环境、工农业相关产品中的耐药菌大量产生。本文对国内外关于微生物对季铵盐类消毒剂的抗性概况、耐药基因及其表达产物的特征,以及相应的研究理论和方法进行了综述。     

季铵盐催化剂及其在绿色制药中的应用

随着环保意识的增强和政策法规的完善,我国的医药行业逐渐走上了绿色发展道路.文章主要从以下几个方面进行了探讨,首先介绍了绿色制药的概念及特点;其次阐述了季铵盐催化剂的定义、分类和合成,并对季铵盐催化剂在绿色制药中的应用进行了分析;最后展望了季铵盐催化剂的发展趋势.     

评价两种消毒剂对IVF实验室微环境和妊娠结局的影响

目的 在辅助生殖体外受精（IVF,in vitro ferrtization）实验室的胚胎操作过程中,根据消毒剂对胚胎质量和妊娠结局的影响,评价季铵盐消毒剂是否比75%酒精消毒液更适合用于IVF实验室。方法 回顾分析2016年1月至9月在我中心行的619例新鲜移植周期,根据IVF实验室使用的消毒剂不同分为两组,A组383例为使用75%酒精消毒组,B组236例使用季铵盐组。对比两组的VOC浓度、获卵数、获卵率、受精率、多精率、卵裂率、优质胚胎率、优质囊胚形成率、着床率、临床妊娠率以及流产率。结果 相比于A组,B组的VOC浓度显著降低;A、B两组的获卵数、获卵率、受精率、多精率、卵裂率、优质胚胎率、优质囊胚形成率和流产率均不具有统计学差异（P＞0.05）;但B组的着床率和妊娠率显著高于A组（P<0.05）。结论 两组对胚胎的体外培养质量没有显著性的影响,但使用季铵盐组相比于75%酒精组胚胎着床率和妊娠率显著提高。因此,季铵盐消毒剂比75%酒精更适合作为IVF实验室消毒剂。     

巯基化壳聚糖季铵盐用于基因输送的研究

目的:本研究诣在对壳聚糖进行修饰,以解决其水溶性问题和基因释放困难的问题。方法:本研究通过2,3-环氧丙基三甲基氯化铵和N-乙酰-L-半胱氨酸对壳聚糖进行修饰,得到巯基化壳聚糖季铵盐(TMC-SH),使其在生理条件下带正电并含有一定量的游离巯基。以TMC-SH为基因载体,形成基因复合物。通过琼脂糖凝胶电泳考察其稳定性,并测定其粒径和ζ-电位。通过DTT条件下的粒径测定,考察基因复合物的还原响应性。结果:核磁结果表明合成TMC-SH的季铵盐取代度为22%,游离巯基-SH含量为79.22μmol/g;琼脂糖凝胶电泳结果表明以TMC-SH为载体形成的二硫键交联的基因复合物TMC-SS/p DNA具有较好的稳定性;而且,二硫键交联以后基因复合物粒径较小,结构更为密实;在还原条件下粒径变大,表明二硫键交联的基因复合物变得疏松,说明其粒径具有还原响应性。结论:对壳聚糖进行低取代度的季铵盐修饰和一定量的巯基化修饰后,其具有较好的包载p DNA能力和还原响应性的基因释放能力。     

壳聚糖季铵盐合成及其抗氧化性能研究

通过Eschweiler Clarke反应得到N,N-二甲基壳聚糖中间体。然后与碘甲烷反应生成水溶性的壳聚糖季铵盐:N,N,N-三甲基壳聚糖碘化铵(TMCI)。检测三种不同取代度的季铵盐产品对羟基自由基(.OH)、超氧自由基(O2-.)的清除率。结果发现:取代度为33.9%时,对.OH的最大清除率为40.2%,对O2-.的最大抑制率为65.6%。并且季铵盐产品对两种自由基的清除率都随着取代度的增大而减小,取代度为80.3%的产品对这两种自由基几乎无清除作用。     

羧甲基化壳聚糖季铵盐与牛血清白蛋白的相互作用研究

应用荧光光谱研究了羧甲基化壳聚糖季铵盐(CMCQA)与牛血清白蛋白(BSA)的相互作用.研究表明:CMCQA对BSA内源性荧光猝灭机制属于CMCQA和BSA形成复合物所引起的静态猝灭.在室温下,二者的结合常数为2.45×104 L/mol,结合位点数为1.04.二者主要靠静电引力相互作用.     

鲍曼不动杆菌耐消毒剂基因检测

目的 了解深圳市人医院鲍曼不动杆菌抗季铵盐类消毒剂基因的检出率及基因型特点.方法 收集深圳市人民医院临床标本中分离鲍曼不动杆菌67株,PCR检测分离株的qacA/B、qacE△1、qacC、qacG和qacJ 5种抗季铵盐类消毒剂基因.结果 67株鲍曼不动杆菌中qacE△l基因阳性42株(62.6％),qacA/B与qacG基因各有一菌株阳性,未检测出qacC或qacJ基因阳性菌株.结论 深圳市人医院鲍曼不动杆菌中抗季铵盐类消毒剂基因检出率较高,主要为qacE△1型.     

双链季铵盐复合邻苯二甲醛消毒液研制及比较

通过将邻苯二甲醛、双链季铵盐与相应助剂进行复配,制备一种新型的复合消毒剂,并进行灭菌消毒试验、清洗效果及稳定性试验。实验证明邻苯二甲醛复合消毒剂浓度在2000 mg/L时对白色念珠菌的杀灭效果达100%。该复合消毒剂原液经45℃恒温放置15 d,邻苯二甲醛的下降率为2.26%左右,稳定性和杀菌能力有明显提高。对油脂清洗率达98%以上,具有消毒清洗双功能。因此邻苯二甲醛复合消毒剂对消化内镜消毒灭菌效果高,耗时短,用法简便,并可降低对医务人员健康的危害性,是值得在医院临床推广使用的高效消毒剂。     

Identification and characterization of GABA, proline and quaternary ammonium compound transporters from Arabidopsis thaliana

Arabidopsis thaliana grows efficiently on GABA as the sole nitrogen source, thereby providing evidence for the existence of GABA transporters in plants. Heterologous complementation of a GABA uptake-deficient yeast mutant identified two previously known plant amino acid transporters, AAP3 and ProT2, as GABA transporters with Michaelis constants of 12.9±1.7 and 1.7±0.3 mM at pH 4, respectively. The simultaneous transport of [1-¹⁴C]GABA and [2,3-³H]proline by ProT2 as a function of pH, provided evidence that the zwitterionic state of GABA is an important parameter in substrate recognition. ProT2-mediated [1-¹⁴C]GABA transport was inhibited by proline and quaternary ammonium compounds.     

In vitro antiseptic properties of an ammonium compound combined with denture base acrylic resin

Background: Denture base acrylic resin is easily colonised by oral endogenous bacteria and Candida spp., and eventually by extra‐oral species such as Staphylococcus spp., Pseudomonadaceae or members of Enterobacteriaceae. This microbial reservoir can be responsive for denture related stomatitis and aspiration pneumonia, a life‐threatening infection especially in geriatric patients. However, the oral and denture hygiene of dependant elderly individuals is extremely poor. Objective: This in vitro study aimed to determine the per cent of a quaternary ammonium compound heat‐polymerised in acrylic resin necessary to obtain denture base displaying antiseptic properties. Design: Acrylic resin discs containing 2–50% ammonium polymer (Poly 202063A; 0% control) were soaked in artificial saliva for 4 weeks. Resin discs were incubated for 24 hours with Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa [37°C, brain–heart infusion (BHI) broth and phosphate‐buffered saline (PBS) buffer] and Candida albicans (30°C, Schaedler broth), in 15 ml (168 discs) and 600 μl (168 discs) of inoculum. Microbial growth was verified at t 0 hours and t 24 hours. Data were recorded as the mean of three colony forming unit (CFU) numerations. The borderline of antimicrobial effect was determined at 0.1% viable cells. Results: In 600 μl of PBS inoculum, resin specimens had a bactericidal effect (E. coli and S. aureus: 2%; P. aeruginosa: 10%) and a fungicidal effect (C. albicans: 50%). Long‐term stability and toxicity in vivo studies are now required. Conclusion: A 2% quaternary ammonium compound polymerised with a denture acrylic resin displayed antiseptic properties after a 4‐week soaking period in artificial saliva. Such antiseptic denture base could help geriatric patients to improve their oral health.     

Influence of immobilized quaternary ammonium group surface density on antimicrobial efficacy and cytotoxicity

Bacterial colonization of medical devices causes infections and is a significant problem in healthcare. The use of antibacterial coatings is considered as a potential solution to this problem and has attracted a great deal of attention. Using concentration density gradients of immobilized quaternary ammonium compounds it was demonstrated that a specific threshold of surface concentration is required to induce significant bacterial death. It was determined that this threshold was 4.18% NR₄⁺ bonded nitrogen with a surface potential of + 120.4 mV. Furthermore, it is shown for the first time that adhesion of constituents of the culture medium to the quaternary ammonium modified surface eliminated any cytotoxicity towards eukaryotic cells such as primary human fibroblasts. The implications of this type of surface fouling on the antimicrobial efficacy of surface coatings are also discussed.     

The process of abscisic acid-induced proline accumulation and the levels of polyamines and quaternary ammonium compounds in hydrated barley leaves

The contents of polyamines and quaternary ammonium compounds (QAC), substances involved in several kinds of stress phenomena, were tested in abscisk acid (ABA)-treated barley leaves (Hordeum vulgare L. cv. Georgie) accumulating pro-line. The characteristic parameters of the accumulation of proline induced by ABA [i.e. kinetics of accumulation, synergistic interaction hormone-K(Na)Cl, enhancing effect of Cl-, inhibiting effect of tetraethylammonium chloride (TEA), D-mannose and glucosamine] were tacking as far as polyamine and QAC content was concerned. Moreover: i) ABA slightly decreased the level of spermine and spermidine, slightly increased that of putrescine but did not influence the level of QAC; ii) the content of polyamines was reduced by KCl; iii) treatment with sorbitol increased the level of polyamines and prevented proline accumulation induced by ABA. These results indicate that there is no relationship between ABA-induced proline accumulation, polyamine level and QAC level; furthermore, accumulation of proline by ABA treatment is possible without increasing the levels of polyamines and QAC.     

Synthesis,physiochemical property and antimicrobial activity of novel quaternary ammonium salts

Twenty-four novel 5-phenyl-1,3,4-oxadiazole-2-thiol (POT) analogues, benzo[d]oxazole-2-thiol, benzo[d]thiazole-2-thiol and 5-methyl-1,3,4-thiadiazole-2-thiol-substituted N,N-bis(2-hydroxyethyl) quaternary ammonium salts (QAS) (5a-d, 6a-d, 7a-d, 10a-d, 13a-d, 16a-d) were prepared and characterised by FTIR, NMR and elemental analysis. Part of target compounds (5d, 6d, 7d, 10d, 13d, 16d) displayed potent antimicrobial effect against ten common pathogens (S. aureus, α-H-tococcus, β-H-tococcus, E. coli, P. aeruginosa, Proteus vulgaris, Canidia Albicans, Cytospora mandshurica, Physalospora piricola, Aspergillus niger) and had relatively low cytotoxity against two human cell lines (HaCat and LO2). TEM and SEM images of E. coli and S. aureus morphologies treated with 7d showed that the antibacterial mechanism might be the QAS fixing on cell wall surfaces and puncturing to result in the release of bacterial cytoplasm. This study provides new information of QAS, which could be used to design novel antimicrobial agents applied in clinic or agriculture.     

Combinatorial materials research applied to the development of new surface coatings IX: An investigation of novel antifouling/fouling-release coatings containing quaternary ammonium salt groups

Polysiloxane coatings containing chemically-bound (“tethered”) quaternary ammonium salt (QAS) moieties were investigated for potential application as environmental-friendly coatings to control marine biofouling. A combinatorial/high-throughput approach was applied to the investigation to enable multiple variables to be probed simultaneously and efficiently. The variables investigated for the moisture-curable coatings included QAS composition, ie alkyl chain length, and concentration as well as silanol-terminated polysiloxane molecular weight. A total of 75 compositionally unique coatings were prepared and characterized using surface characterization techniques and biological assays. Biological assays were based on two different marine microorganisms, a bacterium, Cellulophaga lytica and a diatom, Navicula incerta, as well as a macrofouling alga, Ulva. The results of the study showed that all three variables influenced coating surface properties as well as antifouling (AF) and fouling-release (FR) characteristics. The incorporation of QAS moieties into a polysiloxane matrix generally resulted in an increase in coating surface hydrophobicity. Characterization of coating surface morphology revealed a heterogeneous, two-phase morphology for many of the coatings investigated. A correlation was found between water contact angle and coating surface roughness, with the contact angle increasing with increasing surface roughness. Coatings based on the QAS moiety containing the longest alkyl chain (18 carbons) displayed the highest micro-roughness and, thus, the most hydrophobic surfaces. With regard to AF and FR properties, coatings based on the 18 carbon QAS moieties were very effective at inhibiting C. lytica biofilm formation and enabling easy removal of Ulva sporelings (young plants) while coatings based on the 14 carbon QAS moities were very effective at inhibiting biofilm growth of N. incerta.     

Determination of ammonium and L-Glutamine in hybridoma cell cultures by sequential flow injection analysis

A flow injection anlytical system based on a gas diffusion membrane module for ammonia and an ammonium flow-through potentiometric detector has been set up for measurement of L-glutamine and ammonium ions in hybridoma cell cultures. The main feature of the system is that the same basic analytical concept and equipment is used in both measurements, the only difference being for the determination of L-glutamine, in which the sample flows through an immobilized glutaminase cartridge. The conditions to enable the performance of both analysis consecutively, avoiding potential interferences by unwanted deamination of other compounds in the samples, have been determined. Finally, the proposed system has been compared with reference analytical methods for batch hybridoma cell culture experiments.     

Determination of glycine betaine by pyrolysis-gas chromatography in cereals and grasses

A procedure for determining glycine betaine levels in plants involving pyrolysis-gas chromatography is described. It has been successfully applied to the analysis of 22 species of grasses.