血流感染葡萄球菌菌种分布及耐药特性分析

目的了解血流感染中葡萄球菌的菌种分布及其耐药特性,以指导临床合理使用抗菌药物。方法回顾性分析南昌大学第二附属医院2013年1月至2013年8月期间临床各科室送检的血培养标本中葡萄球菌的菌种分布和耐药特性。采用BACT/ALERT 3D全自动血培养仪进行培养,VITEK2-compact全自动细菌分析仪进行菌种鉴定和药敏试验。WHONET 5.6软件分析数据。结果共分离获得176株葡萄球菌,其中金黄色葡萄球菌24株,占13.6%;路邓葡萄球菌1株,占0.6%;凝固酶阴性葡萄球菌(CNS)151株,占85.8%,人葡萄球菌53株、溶血葡萄球菌32株、表皮葡萄球菌23株及头状葡萄球菌15株居前四位。最常见的葡萄球菌分别为人葡萄球菌、溶血葡萄球菌、金黄色葡萄球菌及表皮葡萄球菌。耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林CNS(MRCNS)检出率分别为29.2%和85.4%,对青霉素耐药率均100.0%,磺胺甲噁唑对MRSA(耐药率仅14.3%)有较强的体外抗菌活性,利福平对MRCNS(耐药率仅18.2%)有较强的体外抗菌活性,均未发现耐万古霉素、利奈唑胺和替加环素的菌株。结论葡萄球菌引起的血流感染菌种分布较广,以人葡萄球菌、溶血葡萄球菌、金黄色葡萄球菌及表皮葡萄球菌为主,人葡萄球菌较金黄色葡萄球菌耐药及多重耐药性严重,但均仍对万古霉素、利奈唑胺、替加环素保持高度敏感。     

金黄色葡萄球菌杀白细胞素ED的研究进展

杀白细胞素ED(leukocidin ED,LukED)是金黄色葡萄球菌产生的双组分成孔杀白细胞素之一,由共转录于一条mRNA的lukE和lukD两个基因编码。LukED可与趋化因子受体CCR5结合以杀伤巨噬细胞、T细胞和树突细胞,或与中性粒细胞、单核细胞和自然杀伤(natural kiler,NK)细胞上的表面受体CXCR1/2结合以促进金黄色葡萄球菌的致病性及系统性感染宿主的死亡。此外,LukED还可结合Duffy 抗原趋化因子受体,使裂解红细胞释放血红蛋白,促进细菌的铁吸收和生长繁殖。LukED的表达受双组分信号转导系统附属基因调节子--毒素抑制子(Agr-Rot)通路和转录调节子RpiRc、SpoVG的调控。lukED基因在金黄色葡萄球菌中广泛流行,与金黄色葡萄球菌所致血流感染、脓疱病及抗生素相关性腹泻密切相关。这些进展对了解LukED的表达调控机制、临床意义及其在细菌致病机制中的作用,开发新的金黄色葡萄球菌感染抗毒素治疗药物具有重要意义     

葡萄球菌自溶素的研究进展

葡萄球菌是人和动物皮肤黏膜的专性寄生菌,目前临床常见的致病菌种主要有金黄色葡萄球菌和表皮葡萄球菌。金黄色葡萄球菌可引起局部化脓感染,也可引起败血症、脓毒血症等全身感染。表皮葡萄球菌主要引起心内膜炎、败血症等,     

大肠埃希菌α溶血素的研究进展

大肠埃希菌α溶血素是RTX毒素家族的典型代表,也是大肠埃希菌肠外感染的重要毒力因子之一。详细介绍了大肠埃希菌α溶血素的成熟、分泌、溶血机理及其生物学效应,这将对大肠埃希菌肠外感染的研究具有重要意义,同时对原核细胞与真核细胞之间的相互作用以及其他细菌溶血素致病机制研究有借鉴作用。     

产SEB金黄色葡萄球菌α-溶血毒素基因缺失菌株的构建

构建产肠毒素B(Staphylococcal enterotoxin B ,SEB)的金黄色葡萄球菌α-溶血毒素（α-hemolysin, α-HL)缺失菌株。首先构建用于α-HL基因敲除的同源重组质粒pMHL-α,经金黄色葡萄球菌RN4220修饰后再通过原生质体转入金黄色葡萄球菌SM-01。含重组质粒pMHL-α的金黄色葡萄球菌SM-01在42℃诱导条件下培养多代,最终筛选出α-溶血毒素基因缺失菌株。经序列分析和血平板溶血实验结果证明最终获得产SEB金黄色葡萄球菌α-HL缺失菌株。为野生型金黄色葡萄球菌的体内遗传操作及构建产超抗原药物金黄色葡萄球菌基因工程菌株提供了一定的理论基础和方法。     

金黄色葡萄球菌RNaseH Ⅰ、RNaseH Ⅱ和RNaseH Ⅲ突变菌株的构建及功能研究

目的:在金黄色葡萄球菌中分别构建RNaseHⅠ、RNaseHⅡ和RNaseHⅢ的突变菌株,并研究它们在金黄色葡萄球菌中的生物学功能。方法:利用同源重组的方法在金黄色葡萄球菌中分别构建RNaseHⅠ、RNaseHⅡ和RNaseHⅢ的插入突变菌株,检测突变株生长速度、溶血活性及外分泌蛋白表达水平与野生型的差异,进一步通过流式细胞术检测突变株外分泌蛋白细胞毒性的改变,同时在体外检测突变株在全血中的存活能力。结果:构建了金黄色葡萄球菌RNaseHⅠ、RNaseHⅡ和RNaseHⅢ的插入突变菌株;表型检测结果显示,与野生型菌株相比,3种突变株的生长速度减慢,溶血素和外分泌蛋白明显减少;流式细胞术检测结果显示3种突变株毒性比野生型菌株减弱;全血杀伤实验结果显示3种突变株在全血中的存活率低于野生型菌株。结论:RNaseHⅠ、RNaseHⅡ和RNaseHⅢ在金黄色葡萄球菌生长繁殖、毒素产生和侵袭机体的过程中有重要作用,它们可能与金黄色葡萄球菌的致病性相关。     

068重组葡萄球菌株诱生白喉抗毒素

以非致病性菌株表达目的抗原,可望诱导有效的免疫应答,其中以革兰阳性的木糖葡萄球菌、肉质葡萄球菌尤为安全、高效.它们与金黄色葡萄球菌有低水平的DNA同源性,但却不产生有致病力的毒素、溶血素、凝集素、蛋白A等,可作为抗原的活载体,有效表达全部或部分抗原成分,诱导持久的体液免疫反应.本实验旨在研究毒性蛋白上某一定义完整的结构域能否被表达在这两种菌株表面,它们能否在小鼠体内诱生中和抗体.已知,白喉毒素(DT)的382～535氨基酸片段是结构完整的区域,为受体结合域DTR.     

金黄色葡萄球菌壁磷壁酸致病与免疫的分子机制研究进展

金黄色葡萄球菌(Staphylococcus aureus)壁磷壁酸(wall teichoic acids, WTAs)是多元醇经由磷酸二酯键共价连接组成的细胞壁表面阴离子糖类聚合物,参与调节细胞壁的稳态并介导细菌毒力。金黄色葡萄球菌WTAs与宿主细胞表面特定的受体结合,可诱导天然免疫和获得性免疫应答。此外,金黄色葡萄球菌WTAs还参与调控毒力基因的表达,有助于细菌的定殖感染,在基因工程靶标治疗和噬菌体药物治疗方面具有广泛的应用前景。本文对金黄色葡萄球菌WTAs的合成进行了概述,综述了WTAs对宿主免疫应答的调控作用,以及在细菌对宿主侵袭与定殖中的致病机制,并归纳WTAs的耐药分子机制和作为药物治疗靶标的研究现状。这些研究为揭示WTAs的致病与免疫分子机制提供研究思路,为预防和治疗金黄色葡萄球菌的感染提供新的策略。     

金黄色葡萄球菌蛋白质相互作用网络及功能

【目的】金黄色葡萄球菌是一种革兰氏阳性菌,是目前最难以对付的病菌之一。它能引起多种感染,特别是在医院环境中。近年来,抗药性金黄色葡萄球菌传染更加严重,已成为公共卫生威胁。由于以前对于金黄色葡萄球菌的实验性研究大都是基于单个基因或者蛋白进行的,为了更好的研究这个物种,有必要从整体上把握金黄色葡萄球菌的蛋白作用机理。【方法】采用系统发生谱、操纵子法、基因融合法、基因邻近法、同源映射法等五种计算方法预测金黄色葡萄球菌蛋白质相互作用网络。【结果】从蛋白组的角度构建了金黄色葡萄球菌蛋白相互作用网络,并对网络进行功能分析。【结论】网络的分析表明金黄色葡萄球菌的蛋白质相互作用网络也服从scale-free属性,发现了SA0939、SA0868、rplD等重要的蛋白。通过对金黄色葡萄球菌的重要的细胞壁合成和信号转导调控蛋白局部网络分析,发现了一些对这两个系统十分重要的蛋白分子,这些信息将为更好的了解金黄色葡萄球菌的致病机理和开发新的药物靶点提供指导。     

金黄色葡萄球菌毒力基因的调控位点

金黄色葡萄球菌的许多致病因子受到细菌的多种遗传位点的调控,各调控位点之间存在复杂作用,各位点的突变可降低金黄色葡萄球菌的致病力。     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV