25株艰难梭菌多位点序列分型

目的比较两种对艰难梭菌多位点序列分型(MLST)的方案并探讨不同来源艰难梭菌之间的关系。方法选取来自不同人群的25株艰难梭菌,分别用Lemee方案(aroE,ddl,dutA,tpi,recA,gmk,sodA管家基因)和David方案(adk,atpA,dxr,glyA,recA,soda,tpi管家基因)进行多位点序列分型,用START系统及Bionumerics软件分析这些位点及等位基因谱的特征。结果位点分析结果表明,Lemee方案中有2株菌的ddl位点为无效位点,其余的6个管家基因有3～5个等位基因,等位基因之间有3～11个多态性位点。非同义突变/同义突变(dN/dS)为0.000 0～0.261 1;David方案中的7个管家基因有3～5个等位基因,等位基因之间有2～9个多态性位点。dN/dS为0.000 0～0.280 6。等位基因图谱特征结果表明,Lemee方案出现了13个ST型别(ST1/2/3/6/7/13/31/39/48/A/B/C/D),ST6(5)为优势型别;David方案共出现11个ST型别(ST2/3/15/35/37/54/55/92/99/102/117),其中ST54(6),ST37(5)为优势型别。来源于成人和婴幼儿的菌株并未形成各自特异的序列型。结论对于艰难梭菌多位点序列分型,David的方案更可取,ST与宿主人群的来源没有明显的相关性。     

产气荚膜梭菌分子分型研究进展

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。     

难辨梭菌分子分型技术

难辨梭菌，抗生素相关腹泻及伪膜性结肠炎的感染因子，是医院内获得性腹泻最常见的病因，并已造成多起老年病人及免疫低下病人的暴发流行。分子分型方法，全细胞可溶性蛋白图谱分析技术，基因组核酸酶切电泳，脉冲场凝胶电泳及ＰＣＲ分型技术。对确定难辨梭菌流行株，控制其传播，指导临床治疗具有重要意义。     

艰难梭菌毒素基因检测及分子流行病学分析

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。     

PCR-核糖体分型技术基因分型艰难梭菌

目的调查区域性的艰难梭菌基因型分布和毒素A、B的携带情况。方法 68株艰难梭菌临床菌株收集自悉尼大学韦斯特米德医院,利用PCR-核糖体分型技术进行基因分型,利用PCR方法检测毒素A、B编码基因tcdA、tcdB。结果 68株菌可分为31种核糖体型(RT),最常见的为RT014(19.1%)和RT002(11.8%);94.1%(64株)的菌株tcdA、tcdB均为阳性。结论悉尼地区主要流行的艰难梭菌基因型为RT014和RT002,绝大部分临床菌株均携带毒素A、B。     

一家县级医院重症医学科住院患者艰难梭菌感染的分子流行病学调查研究

目的 研究县级医院重症医学科(ICU)住院患者艰难梭菌的感染现状,探讨产毒素菌株的分子流行病学特点.方法 收集2017年12月至2019年12月于浙江省温岭市第一人民医院ICU住院并发生腹泻患者的粪便样本,分离培养艰难梭菌并进行毒素基因检测和PCR核糖体分型.结果 共收集355份非重复患者粪便样本,分离到产毒素艰难梭菌...     

艰难梭菌相关性腹泻研究进展

艰难梭菌（Clostridium difficile）是人类肠道中的正常菌群，使用抗菌药物后可导致该菌过度生长。1978年起认识到艰难梭菌与抗生素相关性腹泻有关。随着广谱抗菌药物的广泛应用，全球范围内艰难梭菌相关性腹泻（Clostridium difficile associated diarrhea，CDAD）的发生率不断增高。近年来发现CDAD可出现爆发流行，其流行株出现基因变异，产生毒素的能力增加，患者病死率增高，引起医学界的重视。以下对CDAD研究新进展作一综述。     

我国艰难梭菌流行特征和研究进展

艰难梭菌被认为是抗生素和医疗机构相关性腹泻的主要病原,被美国疾病预防控制中心列为抗生素相关的紧迫公共卫生威胁之一。 近10年来,我国艰难梭菌感染的发生率显著上升,艰难梭菌的研究也日益深入,本研究旨在结合已有报道和研究成果,对我国艰难梭菌的流行特征进行总结,并展望领域内的热点问题,以期对未来研究提供参考。     

艰难梭菌致病相关研究进展

艰难梭菌（Clostridium difficile,Cd）为专性厌氧的革兰阳性杆菌,广泛分布于水、土壤等自然环境以及动物和人的粪便中。其主要致病因子为毒素A（Clostridium difficile toxin A,CdtA）和毒素B（Clostridium difficile toxin B,CdtB）。长期接受广谱抗菌药物、免疫抑制剂或化疗药物治疗,可导致肠道菌群失调,艰难梭菌过度生长并释放毒素,     

艰难梭菌耐药性及耐药机制研究进展

艰难梭菌是导致抗生素相关性腹泻和医院感染性腹泻的最主要病原菌。在欧美等发达国家及地区,艰难梭菌感染都有较高的发病率和死亡率,因此受到高度关注。相比,国内艰难梭菌的研究数据还相对匮乏,尤其临床对其对常用抗生素的耐药性还认识不足。因此,本文就艰难梭菌的耐药性和耐药机制的最新研究进展进行综述。     

Asymptomatic Clostridium difficile colonization as a reservoir for Clostridium difficile infection

Clostridium difficile (CD) infection (CDI) is the leading cause of healthcare associated diarrhea despite intense hospital infection prevention programs. A substantial proportion of the population is asymptomatically colonized with CD, and evidence is mounting that these individuals serve as a reservoir for CDI. The purpose of this review is to discuss the mechanisms by which individuals may harbor toxigenic CD but remain asymptomatic, the evidence that asymptomatically colonized individuals serve as a source of CDI, and the implications of this potential CD reservoir for healthcare infection prevention.     

婴儿艰难梭菌携带状况及菌株特征研究

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。     

汉赛巴尔通体的分子分型研究进展

汉赛巴尔通体是一种新发的人兽共患病病原,呈全球性分布。随着分子生物学技术的发展,多种分子分型方法应用于其流行病学调查,加深了研究者们对汉赛巴尔通体种内变异和系统发育关系的了解。本文就几种常见的分子分型方法在汉赛巴尔通体分子流行病学研究中的应用做一综述。     

艰难梭菌感染实验室诊断方法的研究进展

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.长期应用抗生素、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相关性腹泻(CDAD)的主要因素.CDAD的发病率在全球范围内不断上升,尤其是高产毒株在北美地区引起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CDAD的早期诊断和治疗提供新思路.     

Prevalence of Clostridium difficile colonization at admission to rehabilitation

OBJECTIVES: To assess the prevalence of intestinal colonization with Clostridium difficile (C. difficile) at admission to acute rehabilitation and to identify risk factors associated with colonization. DESIGN: Case-control study. PARTICIPANTS: Consecutive admissions to 2 rehabilitation units (spinal cord injury, brain injury and stroke). SETTING: Free-standing acute rehabilitation facility. INTERVENTIONS: Rectal swabs for culture for C. difficile were obtained at admission and cytotoxin assay performed on all culture positive specimens. Rates of colonization with cytotoxic C. difficile were calculated. Charts were reviewed for medical and demographic factors that may have predisposed patients to colonization, and for possible symptoms at the time of admission. MAIN OUTCOME MEASURES: Percentage of patients with culture and cytotoxin assay positive for C. difficile. Frequency of specific patient characteristics that could predispose to C. difficile colonization. RESULTS: Of admission stool samples, 16.4% tested positive for C. difficile; none of these patients had been identified as colonized before admission. No patients were discordant for C. difficile positivity on culture and presence of a toxigenic strain. No medical or demographic factors were associated with increased risk of colonization, including age (t(52)=-.748, P=.458, not significant [NS]), diarrhea within 24 hours of admission (chi(1)(2) test=.001, P=.973 [NS]), or use of oral or intravenous antibiotics at admission (chi(1)(2) test=.044, P=.834 [NS]). CONCLUSIONS: Patients admitted to acute rehabilitation may have an elevated rate of intestinal colonization with C. difficile without having clinical symptoms. No medical or demographic characteristics were found to be predictive of colonization, however, most of the patients admitted had more than 1 factor that may have increased their susceptibility to infection with this organism. Inadvertent transfer of this organism within the rehabilitation setting may occur because asymptomatic colonization is not recognized.     

The epidemiology of Clostridium difficile infection in patients with cancer

Introduction: Clostridium difficile infection (CDI) is a significant cause of healthcare-associated diarrhoea, and the emergence of endemic strains resulting in poorer outcomes is recognised worldwide. Patients with cancer are a specific high-risk group for development of infection.

Areas covered: In this review, modifiable and non-modifiable risk factors for CDI in adult patients with haematological malignancy or solid tumours are evaluated. In particular, the contribution of antimicrobial exposure, hospitalisation and gastric acid suppression to risk of CDI are discussed. Recent advances in CDI treatment are outlined, namely faecal microbiota transplantation and fidaxomicin therapy for severe/refractory infection in cancer populations. Outcomes of CDI, including mortality are presented, together with the need for valid severity rating tools customised for cancer populations.

Expert commentary: Future areas for research include the prognostic value of C. difficile colonisation in cancer patients and the potential impact of dedicated antimicrobial stewardship programs in reducing the burden of CDI in cancer units.     

Clostridium difficile infection in cancer patients and hematopoietic stem cell transplant recipients

Clostridium difficile has become the most common bacterial cause of nosocomial diarrhea. High rates of C. difficile infection (CDI) coupled with increasing morbidity and mortality attributed to CDI have sparked a renewed interest in this disease. Emergence of hypervirulent strains, rising rates of severe and recurrent infection and associated infection control challenges, and diagnostic and therapeutic dilemmas are major issues in the non-oncology population. Scant data on CDI exist in the cancer/transplant population. The purpose of this article is to describe the epidemiology, pathogenesis and management of CDI in patients receiving cancer chemotherapeutic agents, and in hematopoietic stem cell transplant recipients.     

Xpert艰难梭菌检测系统的临床应用评价

目的评估Xpert艰难梭菌检测系统的临床应用价值。方法选取43份腹泻粪便标本,采用厌氧培养法、VIDAS检测A/B毒素法和Xpert艰难梭菌检测系统检测艰难梭菌,以产毒培养法作为金标准对检测方法进行评价,并比较不同检测方法对临床标本检测结果的一致性。通过自配027型标准菌株模拟粪便标本,验证Xpert艰难梭菌检测系统筛选027型流行株的能力。结果以产毒培养法为金标准,Xpert艰难梭菌检测系统的敏感性和特异性分别为90.9%和93.8%,阳性和阴性预测值分别为83.3%和96.8%。与产毒培养法结果一致性检验Kappa值为0.822(P0.05),与VIDAS检测A/B毒素法结果一致性检验Kappa值为0.419(P0.05);027型标准菌株模拟粪便标本检测结果阳性并报告为027型。结论 Xpert艰难梭菌检测系统能够快速准确地检测粪便标本中的艰难梭菌相关基因,且能准确报告027型高产毒力菌株。