The capsular turnover product of Staphylococcus aureus strain Smith

Abstract The capsular polysaccharide released from the bacterial surface by cell wall turnover during growth exhibited less size heterogeneity and a higher average molecular mass than the polysaccharide extracted from the cell by treatment with lysostaphin or low pH. Treatment of turnover polysaccharide, radiolabelled by growth of the bacteria in the presence of N-acetyl-[³H]-glucosamine, with muramidase B from Chalaropsis released a low molecular weight product chromatographically identical to the peptidoglycan degradation products released from the peptidoglycan-teichoic acid complex by the same treatment. It is concluded that some or all of the capsular polysaccharide released into the culture fluid during growth is derived from peptidoglycan-linked capsular material, solubilised by cell wall turnover.     

金黄色葡萄球菌荚膜多糖研究进展

金黄色葡萄球菌作为引起人和动物发病的一种主要的致病菌,已严重影响到人们的身体健康和畜牧业的发展。致病性金黄色葡萄球菌多数含有荚膜成分,并且这种荚膜成分与金黄色葡萄球菌的毒力和抗噬菌作用有关。主要从金黄色葡萄球菌荚膜多糖的5型和8型血清学分类、分子结构、影响因素、表达调控等方面简要介绍了目前国内外关于金黄色葡萄球菌荚膜多糖的研究进展。     

金葡菌荚膜多糖血清型的研究进展

金葡菌是引起奶牛乳腺炎的一种主要的致病菌,致病性金葡菌多数含有荚膜成分,金葡菌荚膜多糖有11种血清型。从不同血清型荚膜多糖的结构,基因构成,抗吞噬作用,致病性等方面作了介绍,并简要介绍了金葡菌荚膜多糖血清型的国内外研究现状。     

Relationship between capsular types 5 and 8 and phage types in Staphylococcus aureus isolates from cow, goat and ewe milk

Abstract In order to check the relationship between capsular polysaccharide (CP) type 5 and 8 and certain phage patterns, previously described in human Staphylococcus aureus clinical isolates, we typed 100 CP types 5 and 8 S. aureus strains isolated from cow, goat and ewe milk, with the human set of phages. The proportion of typable strains was much less than that found with human strains. The association between CP types 5 and 8 and phage patterns reported for human isolates was only partially confirmed and an original correlation between susceptibility to group III phages and CP type 5 was found.     

Crystal structure of the capsular polysaccharide synthesizing protein CapE of Staphylococcus aureus

Enzymes synthesizing the bacterial CP (capsular polysaccharide) are attractive antimicrobial targets. However, we lack critical information about the structure and mechanism of many of them. In an effort to reduce that gap, we have determined three different crystal structures of the enzyme CapE of the human pathogen Staphylococcus aureus. The structure reveals that CapE is a member of the SDR (short-chain dehydrogenase/reductase) super-family of proteins. CapE assembles in a hexameric complex stabilized by three major contact surfaces between protein subunits. Turnover of substrate and/or coenzyme induces major conformational changes at the contact interface between protein subunits, and a displacement of the substrate-binding domain with respect to the Rossmann domain. A novel dynamic element that we called the latch is essential for remodelling of the protein–protein interface. Structural and primary sequence alignment identifies a group of SDR proteins involved in polysaccharide synthesis that share the two salient features of CapE: the mobile loop (latch) and a distinctive catalytic site (MxxxK). The relevance of these structural elements was evaluated by site-directed mutagenesis.     

金黄色葡萄球菌荚膜分型血清研制及初步应用

为了解中国金葡菌荚膜流行型,用5型和8型国际标准菌株的菌悬液免疫家兔,吸收除去交叉凝集素研制出金葡菌5型和8型荚膜分型血清,并应用于333株临床菌株荚膜分型。该血清效价为1：1280和1：640,与本菌及其它同型菌株玻片凝集反应呈强凝集,与其它型菌株不凝集,且与美国标准血清同时对333株临床分离菌株进行分型比较的符合率为100％。333株金葡地方菌株荚膜分型结果显示,8型菌株占绝对优势,所占百分率为70．9％;5型占6．3％,5型和8型菌株共占77．2％。这与国外金葡菌荚膜5型和8型占70％-80％的报道相似。试验为金葡菌疫苗株选择提供了流行病学依据。     

金黄色葡萄球菌组分疫苗研究进展

临床上,耐药性的金黄色葡萄球菌日益增多,极其耐药的菌株甚至获得了超级耐药细菌的称谓,难以找到有效的抗菌素控制其感染,因而研制有效的疫苗来防治金黄色葡萄球菌感染显得更加重要。对研制开发的金黄色葡萄球菌荚膜多糖疫苗、纤维粘连结合蛋白疫苗、RNAⅢ激活蛋白疫苗以及核酸疫苗等进行了综述。     

细菌荚膜多糖的分离纯化研究进展

荚膜多糖是细菌的保护性抗原和毒力因子,也是细菌疫苗最重要的靶抗原之一,其分离纯化是制作疫苗的首要步骤。本文从去除菌体、收集总糖、去除菌体核酸和蛋白质、去除内毒素等基本工艺步骤,对现有的工艺和目前的工艺进展进行了综述,重点阐述了中空纤维、深层过滤、超滤、酶水解、柱层析等方法在荚膜多糖分离纯化中的应用进展。     

Serotyping of Dutch Staphylococcus aureus strains from carriage and infection

International epidemiological studies have shown that clinical isolates of Staphylococcus aureus are usually capsulated with either type 5 or 8 capsular polysaccharides (CPs). Because all noncapsulated strains were found to be cross-reactive with polysaccharide 336 (336PS) antibodies, the noncapsulated strains were denoted as type 336PS. The capsular types of 162 Dutch methicillin-susceptible S. aureus strains derived from individuals living in the Rotterdam area were determined. The serotype distribution was 28.4% serotype 5, 53.7% type 8, and 17.9% type 336PS. Serotyping was in agreement with genotyping by amplified fragment length polymorphism (AFLP) and multi locus sequence typing (MLST). Among 49 nasal carriage isolates from healthy children 24.5% belonged to serotype 5, 67.3% were type 8 and 8.2% were type 336PS. For 28 adult patients on chronic ambulatory peritoneal dialysis (CAPD) the serotype incidences among carriage isolates obtained from the nose, catheter exit-site, and abdominal skin were 45.1%, 41.2% and 13.7%, respectively. Among S. aureus strains deriving from blood cultures, the serotype incidences were 17.7% serotype 5, 53.2% type 8, and 29.0% type 336PS. Apparently, type 336PS strains are more prevalent (P=0.017) among bacteraemia isolates as compared with the nasal carriage isolates obtained from healthy children and CAPD patients. In conclusion, all Dutch S. aureus isolates belonged to types 5, 8, or 336PS, which is in agreement with data from other countries. Thus, addition of the 336PS conjugate to a type 5- and type 8-CP protein conjugate vaccine would significantly extend the vaccine coverage.     

253株金黄色葡萄球菌耐药现状分析

目的 了解医院金黄色葡萄球菌临床分布情况及其对常用抗菌药物的耐药率,为临床合理使用抗菌药物提供依据.方法 回顾分析医院2010年5月至2011年4月检出的金黄色葡萄球菌,采用VITEK-AMS全自动微生物分析仪进行菌种鉴定和药敏分析.结果 共检出金黄色葡萄球菌253株,菌株的主要来源为痰130株(51.4％)、血液39株(15.4％)、创面24株(9.5％);菌株主要科室分布前3位是神内科35株(13.8％)、ICU30( 11.8％)、脑外科26株(10.3％);其中耐甲氧西林金黄色葡萄球菌( MRSA)为165株(65.2％),MRSA对多种抗菌药物耐药率＞70.0％,MSSA为88株(34.8％),对除青霉素、红霉素外的大多数抗菌药物敏感,未发现耐万古霉素菌株.结论 MRSA检出率高,耐药现状严重,应加强对金黄色葡萄球菌耐药性的监测,并根据药敏试验结果合理使用抗菌药物.     

金黄色葡萄球菌肠毒素

金黄色葡萄球菌是一种重要的病原体,它产生多种类型的毒素,从而引起各种类型的疾病。金黄色葡萄球菌肠毒素(Staphylococcal enterotoxins,SEs),是一组血清学上互不相同的热稳定肠毒素,有10个血清型。由于食入了被SEs污染的食品而主要引起肠胃炎,此外,SEs还是一种强的超抗原,它可以刺激非特异性T细胞增殖。SEs各型之间有着相似的结构和功能。     

A novel capsular polysaccharide from Rhizobium rubi strain DSM 30149

Rhizobium rubi, strain DSM 30149, is a Gram negative phytopathogenic bacterium which produces a linear polysaccharide with the following repeating unit: This new structure was determined by spectroscopical and chemical methods. It presents similar lipophilic features reported for another strain of R. rubi. These contrast with features already known for capsular polysaccharide species from symbiontic members of the Rhizobiaceae family, namely highly anionic polymers.     

The influence of the O-antigen and the capsular polysaccharide on the establishment of PlCmts lysogeny in Klebsiella pneumoniae

The O-antigen of the lipopolysaccharide in Klebsiella pneumoniae caused a significant reduction in the frequency of establishment of PlCmts lysogeny, while the capsular polysaccharide showed no effect on this frequency. The bacterial receptor for PlCmts are the lipopolysaccharide-core oligosaccharides, the results suggest that K. pneumoniae strains with an O-antigen in their lipopolysaccharide have a poorly accessible lipopolysaccharide-core (the PlCmts bacterial receptor), while K. pneumoniae strains lacking the O-antigen have a highly accessible lipopolysaccharide-core. The accessibility of the receptor is independent of the K antigen (capsular polysaccharide).     

A divIVA null mutant of Staphylococcus aureus undergoes normal cell division

DivIVA is involved in placement of the division septum and chromosome segregation in Bacillus subtilis and it plays important roles in cell division or morphogenesis in diverse Gram-positive bacteria. In Staphylococcus aureus, DivIVA is localized at the division septum, but it does not colocalize with the chromosomal origin of replication, as labeled with SpoOJ protein. Unexpectedly, a divIVA null mutant is not impaired in growth, nor is it affected in chromosome segregation or cell morphology.     

金黄色葡萄球菌的快速检测方法

金黄色葡萄球菌是引起食物中毒常见的病原菌之一,其传统检测方法(选择性培养、生化鉴定)步骤多,操作复杂,耗时长、灵敏性不高。近年来以抗原抗体反应为基础的免疫学方法和以DNA为基础的分子生物学技术以其快速性、准确性已经成为微生物检测方法的发展方向。     

合成肺炎链球菌荚膜多糖基因的研究进展

肺炎链球菌是导致婴幼儿和老年人罹患肺炎、脑膜炎、中耳炎等疾病的主要病原体之一,其致病力与位于细菌表面的荚膜多糖密切相关,而荚膜多糖层的薄厚和多糖结构是影响致病力的主要因素。在分子水平探索参与荚膜多糖合成的相关基因,不仅有助于进一步理解肺炎链球菌的致病机理,而且可从基因水平选育高表达荚膜多糖的肺炎链球菌菌株用于多糖疫苗的研发。鉴于此,现就合成肺炎链球菌荚膜多糖基因的作用机制和研究方法作一综述。     

金黄色葡萄球菌的分离及其抗药性的研究

从土壤中分离出金黄色葡萄球菌后,以其为出发菌株,采用梯度培养皿法,利用青霉素、四环素、红霉素、氯霉素和链霉素5种抗生素,对自然界中和经过NaNO2诱变的菌株进行了耐药性菌株的分离及抗性水平的确定。在自然界中分离的金黄色葡萄球菌只对青霉素(80μg/mL)和四环素(60μg/mL)有抗性,而对红霉素、氯霉素和链霉素则没有抗性。经过NaNO2诱变后,金黄色葡萄球菌对四环素(40μg/mL)的抗性降低,但对青霉素(120μg/mL)和其他3种抗生素的抗性均有所增加。     

Iron depletion and virulence in Staphylococcus aureus

Abstract Staphylococcus aureus is able to grow in the presence of extremely low iron concentrations (0.04 μM). In iron-limiting conditions, this species develops alternative metabolic strategies such as highly efficient iron-uptake mechanisms which are only partially shared with S. epidermidis . Here we summarize the mechanisms induced by iron starvation in S. aureus in order to elucidate the virulence characteristics of this bacterium.