快速检测β溶血性A族链球菌抗原对风湿热的诊断价值

对３０例风湿热患者进行快速咽部ＧＡＢＨＳ抗原检测，咽培养及ＡＳＯ测定。咽培养３例阳性，ＡＳＯ增高１８例，而快速链检２７例阳性，其阳性率显著高于ＡＳＯ。快速链检阳性而ＡＳＯ正常的９例中，ＥＳＲ均增快，７例有二尖瓣病变，２例有主动脉病变，由此来看，是ＡＳＯ敏感性不够而非快速链检假阳性。在２０例正常儿童中，有１例快速链检阳性，显著低于风湿热组。     

食物源性C组β型溶血性链球菌感染51例临床分析

目的探讨食物源性C组β型溶血性链球菌感染的临床特点、治疗方法及转归。方法回顾分析河北医科大学第一医院2003-05-28—2003-06-03确诊的51例C组β型溶血性链球菌感染的临床特点。结果51例患者均为食源性感染,临床表现主要为咽充血51例(100%)、发热44例(86%)、扁桃体肿大39例(76.5%)、头痛31例(60.8%)、全身酸痛23例(45.1%)。消化道症状不明显。咽拭子采样17份,细菌培养均阳性;漱口液采样44份,细菌培养阳性23份(52.3%)。培养细菌均为C组β型溶血停乳链球菌类马亚种。51例患者经抗感染治疗均痊愈出院,无并发症。结论与食物污染有关的集体发病患者表现为发热、头痛、全身酸痛、咽痛、咽部充血及扁桃体肿大应考虑到C组链球菌感染的可能,污染食物、咽拭子、漱口液培养可以明确诊断,如未合并严重基础疾病并给予及时有效的抗感染治疗多预后良好。     

C组β溶血性链球菌感染

C组β溶血性链球菌感染是人畜共患疾病，在动物中较常见，在人群中爆发流行极为罕见。人类感染往往源于动物及动物产品，多为食用了被C组β溶血性链球菌污染的食品。因与A组链球菌感染的表现相似，易被误诊为A组链球菌感染，所以临床医生应重视对这种感染性疾病的病原学、流行病学、发病机制、临床表现以及预防措施的认识。     

A组乙型溶血性链球菌膜蛋白抗原纯化及其在风湿性心脏炎发病中意义的探讨

目的　探讨纯化A组乙型溶血性链球菌膜蛋白抗原 (A HSMPA)的方法及其在风湿性心脏炎发病免疫过程中的意义。方法　用反胶束萃取法提纯 ,分别检测提纯前后A HSMPA的成分及抗原性 ,再以A HSMPA及粒细胞 /单核细胞集落刺激因子 (GM CSF)分别刺激风湿性心脏炎组、风湿性心脏病静止期组、急性风湿性关节炎组、自身免疫性疾病组、非风湿性心脏病组、链球菌感染相关性疾病组及健康人对照组的外周血淋巴细胞 ,检测其人类白细胞抗原DR亚型 (HLA DR)分子表达量的改变。结果　 1 提纯后的A HSMPA基本为蛋白成分 ,提纯前后抗原检测外周淋巴细胞促凝血试验结果无显著差异 ,链球菌壁多糖抗体则差异显著。 2 加入A HSMPA孵育后 ,风湿性心脏炎组HLA DR分子表达量的增加为 (19 5 5± 4 32 )× 10 -6A/cell,对照组为 (12 2 2± 6 2 9)× 10 -6A/cell,各组有显著性差异 ;而经GM CSF刺激后 ,以上各组无明显差别。 3 A HSMPA对风湿性心脏炎患者的刺激作用较GM CSF明显。 4 风湿性心脏炎患者随着症状的好转其HLA DR表达量亦减少。结论　 1 反胶束萃取法可提纯A HSMPA并保持其抗原性不变 ,且简便可靠。 2 A HSMPA与HLA DR分子表达量的改变均在风湿性心脏炎发展成为风湿性心脏病过程中起了重要作用。 3 监测A HSMPA刺激后H     

随机扩增DNA多态性技术在A组链球菌分型上的应用

目的 了解A组乙型溶血性链球菌的基因分型状况。方法 采用随机扩增多态性DNA技术(Random amplified polymorphic DNA，RAPD)，对1988～1994年度．从广东城市和农村，1993～1994年度，从湖北、吉林9～11岁学龄儿童分离的179株GAS进行RAPD分析。结果 ①同一T型的菌株有特征性条带，但有些亚型带型间差异较大：②不同T型间可有相同的带型；③分型率比T分型高，达到96．6％；④有主导RAPD型菌株流行的情况存在。结论 RAPD方法对GAS分型及流行病学中有一定的应用价值，可以区别同一血清型不同地区来源的GAS。     

A组链球菌M蛋白二价DNA疫苗表达载体的构建与鉴定

目的构建含A组链球菌M蛋白基因(emm基因)1型和3型特异性抗原决定簇基因的重组质粒。方法用PCR技术从40381137(T1)型和31281187(T3)型A组链球菌中分别扩增emm基因,插入T 载体后测序、blast后分别确定为emm1和emm3基因型,再从emm1和emm3基因分别扩增105 bp目的基因,用聚合酶链反应(polymerase chain reaction,PCR)技术将两目的片段连接起来。插入真核表达载体 pSecTaqB中,阳性质粒克隆经酶切和测序鉴定。结果从40381137(T1)和31281187(T3)A组链球菌株的基因组成功克隆emm基因,经测序及blast后分别确认为emm1型和emm3型;用pst I和BamH I酶切重组质粒pSemml-3、测序均显示插入正确。结论成功构建A组莲球菌的emm1型和emm3型二价真核表达载体,为下一步研究表达功能及表达蛋白的生物活性打下基础。     

奶牛乳腺炎无乳链球菌pgk基因的克隆与序列分析

目的获得牛乳腺炎无乳链球菌分离菌株pgk基因序列,分析其基因与氨基酸的同源性。方法参考Gen-Bank上公布的牛源无乳链球菌pgk基因序列设计合成1对引物,通过PCR扩增获得其序列并进行克隆与测序分析。结果所扩增的pgk基因序列的大小为1 197 bp,负责编码399个氨基酸残基。对比扩增的分离菌株pgk基因序列与GenBank上公布的B群无乳链球菌pgk基因（AE009948）相似性达到99.83%,编码的氨基酸序列相似性达到99.74%。结论该基因序列具有高度的保守性,为进一步对分离菌株的pgk基因进行高效表达及其产物的抗原性研究奠定了基础。     

奶牛乳腺炎无乳链球菌临床分离株fbsA基因的克隆与序列分析

目的克隆并分析牛乳腺炎无乳链球菌内蒙古地区临床分离株表面蛋白fbsA基因核苷酸及编码氨基酸序列,预测其潜在的抗原表位。方法以无乳链球菌内蒙古地区临床分离株为材料,根据GenBank中公布的无乳链球菌fbsA基因序列设计特异性克隆引物,采用同源克隆法,PCR扩增fbsA基因序列,采用DNA Star生物信息学软件预测分析其编码氨基酸的潜在抗原性。结果克隆的fbsA基因序列大小为321bp,编码107个氨基酸残基,与GenBank中公布的B群无乳链球菌fbsA基因核苷酸序列同源性为98.13%,氨基酸序列同源性为99%。预测克隆基因编码氨基酸抗原性指数良好。结论成功克隆出内蒙古地区奶牛乳腺炎无乳链球菌表面蛋白fbsA基因序列,并预测其编码氨基酸具有潜在抗原性为进一步研究其原核表达产物的抗原性及致病机制奠定了基础。     

淡色库蚊β-肌动蛋白基因克隆与序列分析

目的　获取淡色库蚊 β-肌动蛋白全长基因。　方法　采用 RACE法筛选淡色库蚊溴氰菊酯抗性品系 c DNA表达文库 ,获得 β-肌动蛋白基因的 5′和 3′RACE序列 ,然后通过 T/ A克隆插入 p GEM- T质粒载体 ,经过测序、拼接获取全长序列。用 BL ASTp软件将该基因推导的氨基酸序列与蛋白质公共数据库 Swissprot比对、分析。　结果　获得淡色库蚊 β-肌动蛋白基因全长序列 ,总长度为 12 90 bp,开放阅读框为 1132 bp,编码 377个氨基酸 (Gen Bank/ NCBIAY10 0 0 0 5 )。推导的氨基酸序列与公共数据库比对 ,发现与冈比亚按蚊和黑腹果蝇的 β-肌动蛋白的同源性均为 91%。蛋白质的理论分子质量为 4 1.7ku,等电点 (PI)为 5 .4。　结论　获得了淡色库蚊 β-肌动蛋白基因全长序列 ,为蚊虫分子生物学的进一步研究奠定了基础。     

Aβ1-40诱导大鼠脑皮质与海马差异表达基因的克隆与鉴定

我们于 2 0 0 1年 3～ 8月以 β 淀粉样蛋白1 4 0 (ｂｅｔａ ａｍｙｌｏｉｄｐｒｏｔｅｉｎ ,Ａβ1 4 0 )注入脑室建立大鼠ＡＤ模型 ,采用抑制消减杂交 (ＳＳＨ)技术构建Ａβ诱导大鼠皮质与海马差异表达的基因文库 ,旨在探讨Ａβ1 4 0 神经元毒性的分子机制。　　一、材料与方法　　 1 ＡＤ模型的建立 :清洁级成年雄性ＳＤ大鼠 2 0只 ,3月龄 ,体重 3 0 0 ｇ左右 ,购自上海ＢＫ实验动物中心 ,分为 2组。采用立体定向仪 (江湾Ⅱ )向实验组大鼠第 3脑室注射Ａβ1 4 0 (Ｓｉｇｍａ美国 ) 10 μｌ(1μｇ/ μｌ) ,脑室立体定向坐标为 :ＡＰ = 1ｍ…     

Increase in invasive group A streptococcal (Streptococcus pyogenes) infections (iGAS) in young children in the Netherlands, 2022

In 2022, a sevenfold increase in the number of notifiable invasive Streptococcus pyogenes (iGAS) infections among children aged 0–5 years was observed in the Netherlands compared with pre-COVID-19 pandemic years. Of 42 cases in this age group, seven had preceding or coinciding varicella zoster infections, nine were fatal. This increase is not attributable to a specific emm type. Vigilance for clinical deterioration as iGAS sign is warranted in young children, especially those with varicella zoster infection.     

Survival Strategies of Streptococcus pyogenes in Response to Phage Infection

Bacteriophages exert strong evolutionary pressure on their microbial hosts. In their lytic lifecycle, complete bacterial subpopulations are utilized as hosts for bacteriophage replication. However, during their lysogenic lifecycle, bacteriophages can integrate into the host chromosome and alter the host’s genomic make-up, possibly resulting in evolutionary important adjustments. Not surprisingly, bacteria have evolved sophisticated immune systems to protect against phage infection. Streptococcus pyogenes isolates are frequently lysogenic and their prophages have been shown to be major contributors to the virulence of this pathogen. Most S. pyogenes phage research has focused on genomic prophages in relation to virulence, but little is known about the defensive arsenal of S. pyogenes against lytic phage infection. Here, we characterized Phage A1, an S. pyogenes bacteriophage, and investigated several mechanisms that S. pyogenes utilizes to protect itself against phage predation. We show that Phage A1 belongs to the Siphoviridae family and contains a circular double-stranded DNA genome that follows a modular organization described for other streptococcal phages. After infection, the Phage A1 genome can be detected in isolated S. pyogenes survivor strains, which enables the survival of the bacterial host and Phage A1 resistance. Furthermore, we demonstrate that the type II-A CRISPR-Cas system of S. pyogenes acquires new spacers upon phage infection, which are increasingly detectable in the absence of a capsule. Lastly, we show that S. pyogenes produces membrane vesicles that bind to phages, thereby limiting the pool of phages available for infection. Altogether, this work provides novel insight into survival strategies employed by S. pyogenes to combat phage predation.     

化脓链球菌金属结合蛋白Dpr的相互作用蛋白筛选

目的 Dpr蛋白是与细菌毒力密切相关的铁离子结合蛋白,从Dpr蛋白潜在的相互作用蛋白网络出发,通过生物信息学手段分析这些蛋白发挥的功能以及参与的生物过程,揭示Dpr 蛋白在化脓链球菌(Streptococcus pyogenes)中发挥作用的新机制。方法 表达和纯化融合蛋白(GST-Dpr);通过 GST-Pull down 和质谱联用的方式,筛选化脓链球菌中与 Dpr 蛋白相互作用的蛋白。结果 三次独立重复实验共同鉴定到 26 个相互作用蛋白;基于String分析构建各蛋白间的相互作用网络发现,这些相互作用蛋白中有 15 个蛋白与 Dpr 存在直接或间接的联系;利用生物信息学手段分析这些相互作用蛋白的分子功能以及可能参与的生物学途径,发现它们大多能够结合金属离子,主要参与碳代谢、丙酮酸代谢、糖代谢以及糖异生等生物过程。结论 Dpr蛋白可能通过与本研究中鉴定的GAPDH、AccD、Eno、RpsB 和 Fus等蛋白相互作用来共同完成相关的生物学功能。通过建立的Dpr蛋白相互作用蛋白网络,为全面阐述 Dpr 蛋白在细菌定植和毒力方面的功能提供了重要的理论基础和新思路。     

Typing of Streptococcus pyogenes Strains Isolated from Throat Infections in the Region of Aachen, Germany

Background: Changes in the epidemiology of Streptococcus pyogenes infections may be associated with the introduction and reappearance of individual serotypes within a population. Materials and Methods: Typing of 216 consecutive isolates of S. pyogenes from patients with pharyngitis in the region of Aachen, Germany, was performed by sequencing the emm gene, slide-agglutination of the T-antigen and determining the serum opacity reaction (SOR). Results: All 216 isolates were unequivocally emm-typable. emm1 was most common (18.5%), followed by emm12 (15.7%), emm3 (14.4%) and emm28 (13.9%). Only four isolates contained newly validated emm types: emm89 or emm94 were harbored by two isolates each. In one isolate, the sequence type s104 was found. Conclusion: Despite an anticipated selective pressure, the prevalence of emm1 among isolates from throat infections in northwestern Germany remains high, but does not reflect the predominance of emm1 among invasive isolates in Germany. Received: July 25, 2000 · Revision accepted: March 27, 2001     

Healthy elderly people lack neutrophil-mediated functional activity to type V group B Streptococcus

OBJECTIVES: To determine the function of capsular polysaccharide (CPS)-specific immunoglobulin-G (IgG) and neutrophils from older adults in increasing ingestion and killing of type V group B Streptococcus (GBS). DESIGN: Cross-sectional study. SETTING: Outpatient clinic at Baylor College of Medicine. PARTICIPANTS: The subjects were 40 healthy, community-dwelling adults aged 65 and older from Houston, Texas. MEASUREMENTS: The serum level of type V GBS CPS-specific IgG was measured using an enzyme-linked immunosorbent assay. Functional activity was evaluated using an opsonophagocytosis assay. RESULTS: Sera from four subjects promoted efficient neutrophil-mediated phagocytosis and killing of type V GBS (mean log10 reduction+/-standard deviation in colony-forming units (cfu)=1.51+/-0.39). Each had serum CPS-specific IgG concentrations exceeding 1 microg/mL. Sera from 36 subjects did not promote neutrophil-mediated functional activity (mean log10 reduction in cfu=-0.09+/-0.06; P=.025). Only one of these 36 had a CPS-specific IgG concentration exceeding 1 microg/mL. When pooled sera from young adults given type V GBS conjugate vaccine was added at CPS-specific IgG concentrations of 4 microg/mL or 0.4 microg/mL, sera from all subjects promoted neutrophil-mediated killing of type V GBS. No impairment was evident in the neutrophil function of elderly subjects when it was compared with that of young adults. CONCLUSION: CPS-specific IgG and neutrophils from healthy older adults function to ingest and kill type V GBS, but these antibodies are not present in sufficient amounts in most individuals. Further studies should determine whether a type V GBS vaccine induces functionally active antibodies in older people.     

孕晚期B族链球菌感染情况对妊娠结局的影响

目的　研究孕晚期妇女B族链球菌（group B Streptococcus, GBS）感染情况对妊娠结局的影响。方法　采集2016年6月—2018年8月在北京积水潭医院产科进行产前检查的孕35～37周160例待产孕妇的阴道与肛周分泌物,常规用荧光定量PCR法和细菌培养法进行筛查,按照检测结果分为GBS阳性组和GBS阴性组,分析GBS感染情况对孕妇妊娠结局的影响。结果　160例孕晚期妇女GBS阳性者82例,阳性率51.25%（82/160）。2组在年龄、孕周、产次方面进行对比,差异均无统计学意义（P均＞0.05）。GBS阳性组产后出血率（40.24%）、胎膜早破率（20.73%）、宫内感染率（24.39%）均高于GBS阴性组,差异有统计学意义（P均＜0.05）。分离的82株GBS对青霉素G、头孢曲松、氨苄青霉素、利奈唑胺敏感率均为100%;对四环素、克拉霉素、万古霉素、左氧氟沙星、红霉素、克林霉素敏感率分别为7.31%、8.54%、82.93%、68.29%、71.95%、68.29%。结论　孕妇在孕晚期感染GBS将会增加产后出血,宫内感染,胎膜早破的发生率,对妊娠结局产生不良影响。孕妇在孕晚期进行GBS筛查是非常有必要的。     

肺炎链球菌不同菌株自溶酶基因的克隆、序列分析及重组表达

目的克隆肺炎链球菌自溶酶(LytA)的基因序列，并进行重组表达。方法分别提取不同临床分离株的基因组DNA，根据已知肺炎链球菌野生R6株LytA基因序列设计引物，进行PCR扩增，将获得的目的基因片段克隆人原核表达质粒，然后测序；利用生物信息学方法，对不同临床分离株LytA基因序列进行比较分析，同时进行LytA基因的重组表达。结果从不同临床分离株的基因组中均扩增出完整的LytA基因片段，成功构建了重组质粒pGEX-4T-1-LytA。比较不同临床分离株LytA基因的DNA序列及推测的氨基酸序列，发现各株LytA基因序列及氨基酸序列间存在差异。通过异丙基巯基半乳糖(IPTG)诱导，LytA基因在大肠埃希菌JM109中得到高效表达，十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)结果显示pGEX-4T-1-LytA融合蛋白相对分子质量约62000，与理论预测一致。结论序列分析发现各分离株的LytA基因序列及氨基酸序列间存在差异，但同源性极高，推测LytA基因序列保守，可用于疫苗研发。     

重组超抗原金黄色葡萄球菌肠毒素B基因的克隆和序列分析

目的　采用基因工程技术制备金黄色葡萄球菌B型肠毒素 (SEB)。方法　根据SEB已知序列 ,设计一对引物 ,用PCR方法从金黄色葡萄球菌染色体DNA上扩增出基因片段 ,克隆到原核表达质粒 pET32a上 ,转化大肠埃希菌JM10 9感受态细胞 ,经酶切和PCR鉴定 ,然后进行测序。结果　PCR扩增产物大小为 74 0bp ,重组质粒经双酶切PCR鉴定表明已正确重组 ,测序结果与已知序列基本吻合。结论　成功地克隆了金黄色葡萄球菌B型肠毒素 ,为下一步研究发病机制奠定基础。     

幽门螺杆菌尿素酶B亚单位编码基因的克隆与序列分析

目的 幽门螺杆菌(Helicobacter pylori)尿素酶B亚单位的编码基因(ureB)的克隆和序列分析，为H．pylori基因工程疫苗的研究奠定基础。方法应用PCR方法获得国内分离H．pylori菌株MEI，HP27和国际标准参考株H．pylori的ureB基因，通过定向克隆的方法分别插入克隆载体pNEB193中，用质粒酶切电泳和特异PCR方法鉴定重组质粒。克隆基因经测序后进行核苷酸和氨基酸的同源性比较。结果 重组质粒经双酶切后得到1．71kb的ureB基因片段，特异PCR可扩增出ureB基因片段，证实H．pylori ureB基因的重组克隆质粒构建成功。经测序，国内分离H．pylori MEL-HP27的ureB基因全长1710bp( Genbank收录号：AY295085)，编码由569个氨基酸残基组成的肽链，ureB基因序列与GenBank公布的H．pylori相应基因同源性高达96．08％～98．30％，氨基酸序列同源性在98．77％．99．82％之间。结论 成功克隆了MEL-HP27菌株的ureB基因，其核苷酸序列与国际参考株NCTC11637的同源性为97．67％。     

Recurrent neonatal sepsis and progressive white matter injury in a premature newborn culture-positive for group B Streptococcus: A case report

Rationale:Group B Streptococcus (GBS) remains a principal pathogen causing neonatal sepsis and meningitis, particularly in premature infants with relatively insufficient immunity. Recurrence may occur uncommonly, largely associated with subclinical mucosal persistence or repetitive exposure to exogenous sources. White matter injury (WMI) including cystic periventricular leukomalacia (PVL) has been associated with intrauterine infection/inflammation, and neonatal infection as a more significant predictor including postnatal sepsis and recurrent infection, even without microbial neuroinvasion. Furthermore, clinical and experimental evidence of WMI by some bacteria other than GBS without central nervous system invasion has been reported. However, there is little evidence of WMI associated with neonatal GBS sepsis in the absence of meningitis in the literature.Patient concerns:A newborn at 30⁺⁴ weeks’ gestation with low birthweight presented with 2 episodes (with a 13-day interval with no antibiotic therapy) of neonatal sepsis culture-proven for GBS with early-onset presentation after clinical chorioamnionitis via vertical GBS transmission and the associated conditions including prematurity-related neonatal immunodeficiency and persistent mucosal GBS carriage after the first antibiotic treatment. The perinatal GBS infection was complicated by progressive WMI presenting with ventriculomegaly and cystic PVL without a definite evidence of meningitis, intraventricular hemorrhage, and documented cerebral hypoxia or hypoperfusion conditions including septic shock.Diagnoses:Recurrent group B streptococcal sepsis and cystic PVL with ventriculomegaly.Interventions:Two episodes of GBS sepsis were treated with 15-day parenteral antibiotic therapy, respectively.Outcomes:Resolution of the recurrent GBS sepsis without further relapses, however, complicated by WMI and subsequent about 6 months delay in motor development at 12 months’ corrected age.Lessons:This case suggests WMI associated with GBS bacteremia without central nervous system entry by viable GBS and also shows that in premature infants, intrauterine GBS infection with no interventions may lead to extensive and persistent GBS colonization, early-onset and recurrent GBS disease, and WMI. Postnatal as well as intrauterine infection/inflammation controls with maternal prophylaxis may be pivotal for prevention and limiting the magnitude of neurologic injury.