共查询到19条相似文献,搜索用时 140 毫秒
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产气荚膜梭菌是自然界常见的致病菌,广泛分布于人类和动物的胃肠道、食品和环境中,已被美国、欧盟部分国家及日本列为食源性疾病暴发的主要原因之一。 近年来产气荚膜梭菌感染在全球呈上升趋势。 目前该菌的分子流行病学方面研究较多,常用的分子分型方法包括脉冲场凝胶电泳、多位点序列分型、核心基因多位点序列分型、单核苷酸多态性分析、毒素分型等。 分子分型技术对研究产气荚膜梭菌的暴发溯源、流行情况、遗传演化规律与种群特征具有重要意义,同时分子分型方法的不断创新与改进能够提高产气荚膜梭菌感染检测与诊断的有效性、准确性。 相似文献
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目的了解腹泻患者艰难梭菌感染现状,并分析分离菌株的核糖体分型情况。方法收集161例住院腹泻患者粪便标本进行艰难梭菌毒素基因PCR检测,同时进行产毒培养法,并比较2种方法的一致性;对分离的艰难梭菌进行核糖体分型。结果艰难梭菌产毒培养法阳性率为9.94%(16/161),粪便艰难梭菌毒素基因阳性率为9.94%(16/161),2种方法结果差异无统计学(P0.05),一致性较好(Kappa0.75)。培养所得18株艰难梭菌中A、B毒素基因均阴性的2株(11.11%),tcdA~+tcdB~+产毒株15株(83.33%),tcdA~-tcdB~+1株(5.56%)。18株艰难梭菌核糖体分型分为16种型别(GS1~GS16),未发现核糖体分型027型菌株。结论艰难梭菌粪便毒素基因PCR检测可用于临床诊断,未发现本院艰难梭菌暴发流行。 相似文献
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《岭南急诊医学杂志》2017,(2)
目的:研究院内艰难梭菌毒素分离株的毒素情况,对核糖体分型展开研究。方法:抽选出100例腹泻病住院患者未成形的大便制成标本后,完成艰难梭菌的分离培养,鉴定菌落;提取出菌株DNA,并采用PCR法扩增毒素基因tcdA和tcdB;并对核糖体进行分型研究。结果:100例患者培养阳性率为15.00%,共分离出55株艰难梭菌,产毒株占比83.64%;毒素类型集中为A+B+型,占比54.55%;核糖体分型检测相对优势为R4型占比18.18%;R8型占比21.82%。结论:A+和B+毒素型为主要艰难梭菌型;住院腹泻患者主要为院内感染,核糖体分型未提示暴发流行。 相似文献
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《中国感染与化疗杂志》2016,(6)
目的初歩研究上海仁济医院炎症性肠病患者中艰难梭菌的分子流行特征,为炎症性肠病患者中艰难梭菌感染的监控提供证据。方法对2014年6月-2015年6月的222份炎症性肠病腹泻患者粪便标本进行艰难梭菌毒素检测和厌氧培养。采用多位点序列分型(MLST)进行分型,传统PCR方法检测其毒素基因,琼脂稀释法检测艰难梭菌体外药物敏感性,同时对炎症性肠病患者所在病房进行环境中艰难梭菌检测。结果222份粪便标本中艰难梭菌的检出率为13.5%(30/222),克罗恩病和溃疡性结肠炎患者中艰难梭菌检出率为15.7%(22/140)和9.8%(8/82),病房环境共检出4株艰难梭菌。MLST分型22株艰难梭菌为14种ST型,主要型别为ST54型。PCR检测毒素基因显示;TaM+raffl+菌株为主(72.7%,16/22),未检出二元毒素。22株艰难梭菌对氯霉素、四环素、氨苄西林、甲硝唑、万古霉素和美罗培南均敏感,对克林霉素耐药率较高,为63.6%,8株对莫西沙星耐药。结论炎症性肠病腹泻患者中艰难梭菌毒素基因以TcdA+TcdB+型为主,菌株克隆以ST54型为主,该型菌株在病房环境中也有检出。应当密切监测炎症性肠病患者中艰难梭菌的感染毒素基因。 相似文献
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随着分子生物学、基因组学和生物信息学的发展,钩端螺旋体(钩体)分子流行病学的研究也愈发深入。 新的分子分型技术以及大量钩体基因组的测序,使得研究者们对钩体可以有一个全新的认识。 本研究以近年来国内外各种钩体分子分型方法为分类,总结并归纳了16S rRNA基因分型、脉冲场凝胶电泳分析、多位点序列分型、多位点可变数目串联重复序列分型和全基因组测序分析方法,有助于新的菌株型别的发现,揭示不同菌株间的宿主传播关系,地域传播关系,可为今后钩体分子分型方法的应用和钩体病的预防控制提供借鉴。 相似文献
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目的 探讨多位点可变数目串联重复序列分析[multiple-locus VNTR (variable-number tandem repeats) analysis,MLVA]分型方法对产志贺毒素大肠埃希菌分离株的分型效果,初步了解菌株分子流行病学特征。 方法 采用7个VNTR位点对70株产志贺毒素大肠埃希菌分离株进行分析,并根据多态性位点的重复数目利用BioNumerics软件进行聚类分析。 结果 70株菌株被分为46种MLVA型别,O157与非O157菌株可分为A、B两个明显不同的群。除少部分菌株外,不同宿主来源、志贺毒素型别及血清型的非O157菌株与MLVA型别存在较好的相关性。 结论 7个VNTR位点的MLVA分型方案对于产志贺毒素大肠埃希菌的菌株分型、暴发溯源等具有一定的参考价值,但仍需进一步完善。 相似文献
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目的 探讨多位点串联重复序列分析方法(multiple-locus variable-number tandem repeat analysis, MLVA)在嗜麦芽窄食单胞菌分型中的应用。 方法 选用文献报道的12个嗜麦芽窄食单胞菌串联重复序列位点及引物,采用聚合酶链反应(PCR)和琼脂糖凝胶电泳,根据凝胶电泳图谱计算出各位点的串联重复单元拷贝数,通过BioNumerics(Version 4.0, Applied Maths BVBA, Belium)聚类分析。 结果 设置12个位点串联重复单元拷贝数100%的相似性为判断标准,可将106株嗜麦芽窄食单胞菌分为34个MLVA基因型,流行病学上有关联的菌株具有相同的基因型。设置12个位点串联重复单元拷贝数45%相似性为判断标准,将106株菌株分为11个群,相同的地域、分离来源和分离部位的菌株具有相关性。 结论 串联重复序列位点分型技术具有简便、快速、特异、可比性、可重复性和高鉴别力等优点,适合嗜麦芽窄食单胞菌的分子流行病学研究。 相似文献
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Toxigenic Clostridium difficile is the etiologic agent of C. difficile-associated diarrhea (CDAD), the most common cause of nosocomial diarrhea. Cross-infection between patients and transmission through the environment and medical personnel are important factors in the acquisition of CDAD. In order to understand differences in epidemiology and pathogenesis, a number of typing schemes have been developed. We will review the typing methods used to study the epidemiology of C. difficile infections and how they have evolved from a phenotypic identification to state of the art molecular methods, detecting genetic polymorphisms among strains. These molecular methods include PCR-based methods (arbitrarily primed-PCR [AP-PCR] and PCR ribotyping), restriction endonuclease analysis (REA) and pulse field gel electrophoresis (PFGE). The application, usefulness and feasibility of these methods are compared and discussed. Finally, the role of genomics as a tool to investigate CDAD is introduced. 相似文献
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Chapin KC Dickenson RA Wu F Andrea SB 《The Journal of molecular diagnostics : JMD》2011,13(4):395-400
Performance characteristics of five assays for detection of Clostridium difficile toxin were compared using fresh stool samples from patients with C. difficile infection (CDI). Assays were performed simultaneously and according to the manufacturers' instructions. Patients were included in the study if they exhibited clinical symptoms consistent with CDI. Nonmolecular assays included glutamate dehydrogenase antigen tests, with positive findings followed by the Premier Toxin A and B Enzyme Immunoassay (GDH/EIA), and the C. Diff Quik Chek Complete test. Molecular assays (PCR) included the BD GeneOhm Cdiff Assay, the Xpert C. difficile test, and the ProGastro Cd assay. Specimens were considered true positive if results were positive in two or more assays. For each method, the Youden index was calculated and cost-effectiveness was analyzed. Of 81 patients evaluated, 26 (32.1%) were positive for CDI. Sensitivity of the BD GeneOhm Cdiff assay, the Xpert C. difficile test, the ProGastro Cd assay, C. Diff Quik Chek Complete test, and two-step GDH/EIA was 96.2%, 96.2%, 88.5%, 61.5%, and 42.3%, respectively. Specificity of the Xpert C. difficile test was 96.4%, and for the other four assays was 100%. Compared with nonmolecular methods, molecular methods detected 34.7% more positive specimens. Assessment of performance characteristics and cost-effectiveness demonstrated that the BD GeneOhm Cdiff assay yielded the best results. While costly, the Xpert C. difficile test required limited processing and yielded rapid results. Because of discordant results, specimen processing, and extraction equipment requirements, the ProGastro Cd assay was the least favored molecular assay. The GDH/EIA method lacked sufficient sensitivity to be recommended. 相似文献
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Infection with Clostridium difficile is a growing concern because of the increasing prevalence and spread of nosocomial infections. Emergence of the hypervirulent 027/NAP1/BI strain is also notable. Existing diagnostic methods have low sensitivity or are time-consuming. Therefore, establishing a rapid and accurate microbiological diagnostic assay is needed. We evaluated the Xpert C. difficile assay (Xpert CD assay; Cepheid, USA) to detect toxigenic C. difficile. This assay is a real-time multiplex PCR assay that can be used to detect toxigenic C. difficile strains and differentiate the C. difficile presumptive 027/NAP1/BI strain. A total of 253 loose stool specimens were collected and toxigenic cultures, VIDAS C. difficile A & B assays (VIDAS CDAB assay; bioMérieux, France), and the Xpert CD assay were performed. In comparison to toxigenic cultures, the sensitivity, specificity, and positive and negative predictive values were 100%, 94.6%, 83.1%, and 100%, respectively, for the Xpert CD assay and 40.8%, 98.0%, 100%, and 88.9%, respectively, for VIDAS CDAB assay. Because of the low prevalence of the PCR ribotype 027 in Korea, the evaluation of the usefulness of the Xpert CD assay for screening for the 027 strain was limited. The Xpert CD assay provides great sensitivity in diagnosing toxigenic C. difficile infection. In addition, this method has excellent usability because it is simple and fast. 相似文献
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目的调查婴儿艰难梭菌的携带状况及菌株特征。方法收集2015年8-11月在该院住院或门诊治疗的1岁内婴儿粪便标本238份,利用免疫层析法快速初筛艰难梭菌,阳性标本再利用CDIF平板进行厌氧培养以获得菌株,利用PCR方法检测艰难梭菌毒素A、B的编码基因tcdA、tcdB和二元毒素编码基因cdtA、cdtB,运用slpA测序分型(slpA ST)方法对菌株进行基因分型。结果 238份粪便标本共分离出50株艰难梭菌,3月、3~6月和6月至1岁三组婴儿艰难梭菌的分离率分别为9.3%,17.6%和27.3%,三组见比较差异有统计学意义(χ~2=6.940,P=0.0310.05)。52.0%(26/50)的菌株为产毒株,其中69.2%(18/26)的菌株产毒模式为tcdA+tcdB+cdtA-cdtB-。50株艰难梭菌可分为11种slpA ST型,产毒株最常见的基因型为slpA ST fr-02和kr-02,而非产毒株则为xr-03。结论 1岁内婴儿艰难梭菌携带率较高,且过半为产毒株,大多同时产毒素A和B。产毒株与非产毒株的基因型存在差别。 相似文献
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艰难梭菌是一种专性厌氧革兰阳性芽孢杆菌,一般认为是环境和人类肠道中的正常菌群。过度应用抗生素、免疫抑制剂或化疗药物使耐药的艰难梭菌产毒株过度繁殖并释放毒素是导致艰难梭菌感染(Clostridioides difficile infection, CDI)的主要因素。CDI的发病率在全球范围内不断增加,尤其是高产毒株在北美地区造成了医院内的暴发流行,引起了世界范围的关注。在此对艰难梭菌的致病机制和实验室诊断方法的研究进展进行阐述,为艰难梭菌相关性腹泻的早期诊断和治疗提供新思路。 相似文献
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基于表型特征、化学分类学及系统发育学等研究,艰难梭菌已被归入拟梭菌属,并重命名为艰难拟梭菌。 近年来,随着多重耐药艰难拟梭菌不断出现,导致抗生素治疗失效以及感染复发病例明显上升。 目前欧美部分国家已建立完善的艰难拟梭菌感染监控体系及相应的临床诊疗指南,但我国相关工作起步较晚。 同时,我国仍存在抗生素使用不规范甚至滥用等现象,造成艰难拟梭菌感染的防控及诊治面临较大挑战。 本研究主要介绍了艰难拟梭菌重命名及相关致病因子研究进展,为在国内修正和规范化使用“艰难拟梭菌”名称、推动国内艰难拟梭菌研究进程及致病机制研究等提供必要的参考依据。 相似文献
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Lee YT Lin DB Wang WY Tsao SM Yu SF Wei MJ Yang SF Lu MC Chiou HL Chen SC Lee MC 《Diagnostic microbiology and infectious disease》2011,70(2):175-182
We used molecular typing methods to investigate an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) infections in a respiratory care ward in Taiwan. From March to June 2006, the incidence of MRSA infection increased 3.75-fold. The overall carrier rates among the health care workers (HCWs) were 31.3% (total S. aureus), 16.4% (MRSA), and 14.9% (methicillin-sensitive SA, MSSA). Pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), antibiograms derived from susceptibility testing of MRSA isolates, and multiplex polymerase chain reaction (PCR) provided strong epidemiologic and microbiologic evidence that the outbreak of MRSA infections at our hospital was linked to the same PFGE pulsotype A SCCmec type II, pvl-negative, MLST ST5 strain of MRSA isolated from seven HCWs and five patients. The outbreak was controlled by application of topical fucidin ointment to the anterior nares in all colonized HCWs. Multiplex PCR combined with PFGE and MLST is a feasible method for outbreak investigations in routine clinical laboratories. 相似文献