艰难梭菌相关性腹泻实验室检测新进展

有资料显示,15%～25%的抗生素相关性腹泻(AAD)以及90%的伪膜性肠炎是由艰难梭菌(Clostridium difficile)引起的,新近暴发的涉及美国38个州及欧洲17个国家的艰难梭菌相关性腹泻(CDAD),与2003年加拿大和美国新出现的高致病菌株有关,具有症状明显加重、复发率提高、死亡率上升的特点.     

宁夏地区临床腹泻患者艰难梭菌感染及危险因素

目的 了解宁夏医科大学总医院住院腹泻患者艰难梭菌感染(CDI)状况,并进行危险因素分析。方法 收集宁夏医科大学总医院2019年1月1日-2020年12月1日530份腹泻粪便标本,进行厌氧培养、普通聚合酶链式反应(PCR)法检测毒素基因,采用1∶2病例对照研究(CDI组36例∶非CDI组72例)临床病历资料,分析CDI危险因素。结果 530份粪便中检出艰难梭菌(CD)38株(检出率7.2%,38/530),产毒型CD 36株(感染率6.8%,36/530),以tcdA+tcdB+为主(29株,80.6%),多因素二元Logistic回归分析显示：CDI独立危险因素为有六个月内住院史(OR=5.612,95%CI 1.520～20.720,P=0.010)、患有胃肠道疾病(OR=4.240,95%CI 1.189～15.123,P=0.026)和患有肝胆疾病(OR=6.253,95%CI 1.671～23.405,P=0.006)。结论 为预防CDI,建议临床对具有六个月内住院经历、罹患消化道疾病、肝胆疾病独立危险因素患者进行早期识别,以预防艰难梭菌在医院感染及流行。     

艰难梭菌毒素A＆B测定在医院腹泻患者中的应用

目的探讨艰难梭菌毒素AB测定在医院腹泻患者中的应用价值。方法采用VIDAS艰难梭菌AB毒素检测试剂对某院47例住院的腹泻患者粪便标本进行毒素检测,并结合细菌常规培养、临床资料及治疗进行综合分析。结果 47例腹泻患者中,7例(14.89%)艰难梭菌毒素检测阳性,此7例阳性结果均与临床诊断和/或治疗相符。结论该院艰难梭菌感染形势较为严峻,VIDAS艰难梭菌AB毒素检测可提供简单、准确、快速的检测结果,值得推广应用。     

艰难梭菌谷氨酸脱氢酶抗原及毒素检测试剂盒对艰难梭菌感染诊断价值的Meta分析

目的探讨艰难梭菌谷氨酸脱氢酶(GDH)抗原及毒素检测试剂盒(简称CD快速检测试剂盒)对艰难梭菌感染(CDI)的诊断价值。方法按照纳入和排除标准筛选文献,检索有关CD快速检测试剂盒诊断CDI的文献,采用诊断准确性研究的质量评价工具QUADAS进行质量评价,应用Meta DiSc 1.4软件进行Meta分析。结果共纳入8篇文献2 852例研究对象。纳入文献均为高质量文献,异质性检验显示无阈值效应,但存在其他原因导致的非阈值性异质性。采用随机效应模型进行Meta分析,结果显示,CD快速检测试剂盒GDH抗原检测诊断CDI的合并灵敏度、特异度、阳性似然比、阴性似然比、诊断优势比及其95%CI分别为0.96(0.94,0.98)、0.96(0.95,0.97)、20.07(13.47,29.92)、0.04(0.03,0.07)、409.35(168.01,997.39);毒素检测诊断CDI分别为0.54(0.48,0.59)、1.00(0.99,1.00)、64.23(18.90,218.33)、0.48(0.37,0.62)、142.74(40.94,497.61)。试剂盒GDH抗原、毒素检测诊断CDI的受试者工作曲线下面积(AUCSROC)分别为0.9877、0.9529,Q*指数分别为0.9718、0.9228。结论 CD快速检测试剂盒抗原检测部分灵敏度、特异度、阳性似然比、阴性似然比及诊断优势比均较高,毒素检测部分虽灵敏度欠佳,但特异度较高,可作为缺乏专业设备条件的地区及医院CDI的初筛试剂盒。     

腹泻患儿艰难梭菌感染的调查研究

目的调查苏州市腹泻患儿艰难梭菌感染(CDI)的状况并分析其相关因素,为降低其感染率提供参考依据。方法以2013年6-10月在苏州大学附属儿童医院消化科住院的腹泻患儿共176例作为研究对象,采用实时荧光PCR方法检测艰难梭菌看家基因tpi及A/B毒素基因tcdA/tcdB进行艰难梭菌初筛及致病性诊断,探讨其危险因素。结果在176例腹泻患儿中初筛艰难梭菌阳性34例,阳性率为19.32%,确诊CDI 22例,感染率12.50%,其中男性占59.09%、女性占40.91%;统计分析表明年龄、性别、城乡分布及有无抗菌药物应用史差异均无统计学意义。结论腹泻患儿中艰难梭菌感染率较高,艰难梭菌感染率与患儿年龄、性别、城乡分布及抗菌药物应用史无显著相关。     

艰难梭菌感染实验室检测方法进展

<正>艰难梭菌(Clostridium difficile,CD)是一种专性厌氧的革兰阳性芽孢杆菌,1935年首次在新生儿肠道正常菌群中被分离出来。1978年起人们发现该细菌是引起抗生素相关性腹泻、医院性腹泻及假膜性肠炎的主要病原体。有资料显示,25%~30%的抗生素相关性腹泻以及90%以上的假膜性肠炎均是由CD引起的,美国由艰难梭菌感染(Clostridium-difficile infection,CDI)所致的病死     

住院腹泻患者艰难梭菌检测与分析

目的通过对住院腹泻患者粪便标本中的艰难梭菌进行筛查和不同时期检出率的比较,了解某院腹泻患者艰难梭菌的感染情况。方法收集该院2009年2—12月和2011年4—7月住院腹泻患者粪便标本106份,进行厌氧培养和API鉴定,对培养鉴定获得的菌株应用聚合酶链反应（PCR）扩增法进行A、B毒素及二元毒素基因检测;酶联荧光免疫法检测毒素A/B。结果 106份标本中,厌氧培养艰难梭菌阳性16株（15.09%）。16株菌经PCR扩增,A、B毒素均阳性,二元毒素均阴性。直接毒素A/B检测阳性率为12.26%（13/106）,与厌氧培养阳性率比较,差异无统计学意义（χ^20.16,P〉0.05）。2009年2—12月和2011年4—7月两个时期的标本厌氧培养艰难梭菌阳性率分别为22.81%（13/57）、6.12%（3/49）,两者比较,差异有统计学意义（χ^25.73,P〈0.05）;毒素A/B检出率分别为17.54%（10/57）、6.12%（3/49）,差异无统计学意义（χ^23.18,P〉0.05）。艰难梭菌检测阳性患者住院期间均使用过头孢类、喹诺酮类、碳青霉烯类、广谱青霉素、克林霉素等其中一种或多种抗菌药物。结论该院艰难梭菌相关性腹泻比较严重,抗菌药物的使用是诱使艰难梭菌感染的重要因素。     

郴州市住院腹泻患者艰难梭菌感染状况及其基因特征

目的 通过对住院腹泻患者粪便中艰难梭菌的分离培养和毒力基因检测及分型,了解郴州市住院腹泻患者艰难梭菌感染状况。方法 收集2020年10-12月湘南学院附属医院、郴州市第一人民医院和郴州市第三人民医院住院腹泻患者粪便标本306例,厌氧培养法分离艰难梭菌菌株,采用荧光聚合酶链反应(RT-PCR)检测A、B毒素基因tcdA、tcdB及二元毒素基因cdtA、cdtB,并对分离的艰难梭菌菌株进行多位点序列分型(MLST)。结果 郴州市住院腹泻患者产毒艰难梭菌核酸阳性率为8.17%(25/306),>60岁患者感染风险更高(χ²=5.499,P=0.019); 306份标本中分离出17株艰难梭菌,粪便标本荧光PCR检测有25份阳性,二者比较有统计学差异(P=0.008),毒力基因检测均为tcdA⁺tcdB⁺,未检出二元毒素;选取7株艰难梭菌进行MLST分型,分出5个ST型,ST54型(3株)、ST129型(1株)、ST98型(1株)、ST53(1株)和ST631(1株)。结论 郴州市住院腹泻患者艰难梭菌感染率较低,感染毒素类型...     

艰难梭菌毒力与芽孢研究进展

艰难梭菌（Clostridium difficile,CD）是梭菌属中的一种专性厌氧、有芽孢、产毒素的革兰阳性粗大杆菌,因其生长营养要求较高,分离培养困难,故得此名。一般栖生在人或动物肠道内,通过粪-口途径引起外源性感染,也可以在使用大量抗菌药物后由肠道栖生的艰难梭菌引起内源性感染。目前,艰难梭菌是唯一能引起医院感染的厌氧菌,也是引起医院感染病原体中唯一能形成芽孢的细菌。约25％的抗生素相关性腹泻 (antibiotic associated diarrhea,AAD),75％的抗生素相关性肠炎(antibiotic associated colitis,AAC)和近100％的假膜性肠炎(pseudomembranous colitis,PMC)均由此菌引起,统称为艰难梭菌相关性疾病(Clostridium difficile associated disease,CDAD)。近年来,随着抗菌药物的广泛应用,艰难梭菌耐药性增强,以及高致病菌株出现,导致CDAD发病率及致死率不断增高。目前,国内外已有诸多文献详细介绍了艰难梭菌生物学特性、实验室检测及耐药机制,故本文就艰难梭菌毒力与芽孢予以简要综述。     

我国住院腹泻患者艰难梭菌感染率的荟萃分析

目的运用荟萃分析评价我国住院腹泻患者艰难梭菌的感染情况,为艰难梭菌的医院感染控制提供依据。方法系统检索PubMed、中国期刊全文数据库(CNKI)、中国生物医学文献数据库、万方数据库以及维普信息资源系统中建库至2016年9月发表的有关我国住院腹泻患者艰难梭菌感染情况的研究文献,参考疾病患病率或发病率研究质量评价准则评价文献质量,采用R软件进行分析,根据患者科室、地区和性别执行亚组分析,通过异质性检验以选择固定效应模型或随机效应模型对感染率进行合并,并用敏感性分析及漏斗图评价发表偏倚。结果共纳入31篇文献,总样本量为9 600人,艰难梭菌整体合并感染率为19%(95%CI:16~22),抗菌药物相关腹泻患者的艰难梭菌感染率为19%(95%CI:13~24);亚组分析显示:不同科室类别、地区、性别的患者,其艰难梭菌感染率存在差异且有统计学意义。结论我国住院腹泻患者艰难梭菌感染率较高,医院需加强对重点人群艰难梭菌感染的防控与管理。     

Risk factors for Clostridium difficile toxin-associated diarrhea

The hospital-wide attack rate for Clostridium difficile-associated diarrhea at our tertiary-care university hospital was 0.02 per 100 patient discharges (0.02%) in 1982, but 0.41% and 1.47% in 1986 and 1987, respectively, with a peak incidence of 2.25% in the fourth quarter of 1987. Hospital antibiotic usage patterns showed concurrent increased use of third-generation cephalosporins, and intravenous vancomycin and metronidazole. Thirty-seven cases selected for study were older than 37 control patients, more likely to have an underlying malignancy and less likely hospitalized on the obstetrics/gynecology service. Their mean duration of hospitalization prior to diagnosis was 21 days, versus a mean total length of stay of eight days for controls. All cases received antibiotics, compared to 24 of the controls. Cases were given more antibiotics for longer periods, and more often received clindamycin, third-generation cephalosporins, aminoglycosides and vancomycin. Gender, race, duration of hospitalization, prior surgery and antiulcer therapy were not significant by logistic regression analysis. Epidemiologic variables with significantly different adjusted odds ratios (95% confidence intervals) were age greater than 65 years (14.1, 1.4-141), intensive care unit residence (39.2, 2.2-713), gastrointestinal procedure (23.2, 2.1-255) and more than ten antibiotic days (summation of days of each antibiotic administered) (16.1, 2.2-117). Control measures included encouraging earlier isolation and treatment of suspected cases and formulary restriction of clindamycin, with use of metronidazole for therapy of anaerobic infections. By the second half of 1988, the attack rate had dropped progressively to 0.74%.     

Active and passive immunization against Clostridium difficile diarrhea and colitis

Clostridium difficile, a gram-positive bacterium, is the major cause of hospital-acquired infectious diarrhea and colitis in industrialized nations. C. difficile colonization results from antibiotic administration and subsequent loss of protection provided by intestinal flora. C. difficile induced-colitis is caused by the release of two exotoxins, toxin A and B. Host factors including advanced age, pre-existing severe illness and weakened immune defenses predispose individuals to symptomatic infection. The generation of antibody responses to toxin A through natural exposure is associated with protection from disease. In addition, an inability to acquire immunity to toxin A puts individuals at risk for recurrent and/or severe disease. Immunological approaches for the management of this disease are being developed which could reduce the reliance on antibiotics for treatment and allow for re-establishment of the natural barrier provided by an intact commensal flora. An active vaccine and various immunotherapeutic strategies under evaluation may prove to be effective against severe or relapsing C. difficile infection.     

108例艰难梭菌相关性腹泻患者的临床诊治分析

目的回顾性研究三甲综合性医院艰难梭菌感染的流行及治疗。方法收集2015年1月-2016年6月医院收治的852例腹泻患者的粪便标本,进行厌氧培养和药敏试验,对艰难梭菌培养阳性的108株菌株进行毒素基因(tcdA、tcd B)的PCR检测和多位点序列分型。收集所有患者的临床资料,归纳ICU腹泻患者感染艰难梭菌的影响因素。结果艰难梭菌阳性率为12.68%(108/852),毒素基因tcd A和tcd B均阳性占89.81%(97/108)。多位点序列分型分离出33种ST型,主要为ST54型(17.59%)、ST3型(15.74%)、ST8型(8.33%)、ST2型(7.41%)和ST35型(6.48%),eBURST分析33个ST型无明显的同源性。性别(男性)、年龄和APACHE II评分是ICU腹泻患者艰难梭菌感染的影响因素(P<0.05)。消化内科、ICU、康复科和血液科为检出艰难梭菌感染最多的科室。甲硝唑和万古霉素保持高度敏感,无耐药菌株检出。108例CDI中41例采用非药物治疗,其中好转33例,无效6例,死亡2例。病情较重行药物治疗67例,选择甲硝唑加/不加万古霉素抗CDI治疗,其中好转56例,无效7例,死亡4例。结论腹泻患者中艰难梭菌感染发生率较高,但无高产毒株检出,无证据表明存在艰难梭菌感染的传播和暴发流行,多个科室应列为艰难梭菌感染的感控哨点科室,应规范标本送检,提高送检率。     

Predicting Clostridium difficile toxin in hospitalized patients with antibiotic-associated diarrhea.

OBJECTIVE: Clostridium difficile infection is implicated in 20%-30% of cases of antibiotic-associated diarrhea. Studying hospitalized patients who received antibiotic therapy and developed diarrhea, our objective was to compare the clinical characteristics of patients who developed C. difficile-associated diarrhea (CDAD) with those of patients with a negative result of a stool assay for C. difficile toxin. METHODS: A prospective study was done with a cohort of 217 hospitalized patients who had received antibiotics and developed diarrhea. Patients with CDAD were defined as patients who had diarrhea and a positive result for C. difficile toxin A/B by an enzyme immunoassay of stool. The variables that yielded a significant difference on univariate analysis between patients with a positive assay result and patients with a negative assay result were entered into a logistic regression model for prediction of C. difficile toxin.Setting. A 900-bed tertiary care medical center. RESULTS: Of 217 patients, 52 (24%) had a positive result of assay for C. difficile toxin A/B in their stool. The logistic regression model included impaired functional capacity, watery diarrhea, use of a proton pump inhibitor, use of a histamine receptor blocker, leukocytosis, and hypoalbuminemia. The area under the receiver operating characteristic curve for the model as a predictor of a positive result for the stool toxin assay was 0.896 (95% confidence interval, 0.661-1.000; P<.001), with 95% specificity and 68% sensitivity. CONCLUSIONS: Our results may help clinicians to predict the risk of CDAD in hospitalized patients with antibiotic-associated diarrhea, to guide careful, specific empirical therapy, and to direct early attention to infection control issues.     

Clostridium difficile

Clostridium difficile is the leading cause of healthcare‐associated infectious diarrhea. Although C difficile is part of normal flora in some healthy individuals, patients with selective risk factors are often vulnerable to the toxigenic potential of this virulent healthcare pathogen. The spectrum of C difficile infection (CDI) is highly variable, ranging from mild to severe illness, presenting with single to multiple disease recurrences. Current approaches to treatment are based on severity of illness, number of recurrences, and clinical presentation. Oral vancomycin and metronidazole have formed the foundation for treatment of CDI, but therapeutic failures are commonly reported, especially involving hypervirulent clones. Alternative therapies, including newer antimicrobials, probiotics, immunotherapy, and fecal transplantation, have all met with varying degrees of efficacy. Although toxigenic culture (TC) testing from anaerobic culture remains the gold standard, newer technologies, including enzyme immunoassay, common antigen (glutamate dehydrogenase) testing, and real‐time polymerase chain reaction (PCR) are less time‐consuming and rapid. However, TC and PCR have reported high specificity and sensitivity when compared with other laboratory tests. Because of the significant morbidity and mortality associated with CDI, a high index of suspicion is warranted. Prevention and eradication of CDI require a multidisciplinary approach, including early disease recognition through appropriate surveillance, implementation of effective contact isolation strategies, adherence to environmental controls, judicious hand hygiene, evidence‐based treatment, and management that includes antibiotic stewardship, continuous education of healthcare workers, and administrative support.     

Risk factors for Clostridium difficile cytotoxin-positive diarrhea after control for horizontal transmission

OBJECTIVE: This study identifies risk factors that predispose hospitalized patients to diarrhea caused by Clostridium difficile. DESIGN: Unlike most previous studies, this case-control study accounts for horizontal (person-to-person) transmission of this infectious organism by matching on location. SETTING: An urban community hospital of 600 beds with both primary care and referred patients. PATIENTS: Both the 36 cases and the 36 controls came from billing printouts for C difficile cytotoxin assays. Exclusion criteria included out-patient specimens and stays of 38 days or more. Controls had negative assays and were individually matched on the basis of the floor and by the general date of specimen collection. RESULTS: Cases had a longer mean duration of antibiotic use (6.7 versus 4.1 days, p = .006). Of the other 22 factors that were evaluated for their risk of predisposing to C difficile, only clindamycin (OR = 3.50, p = .09) and third-generation cephalosporins (OR = 3.00, p = .04) showed any association. The odds ratio for third-generation cephalosporins in the absence of clindamycin was 3.50 (p = .09). Data were collected by physicians who were not blinded. CONCLUSIONS: This study found that the clindamycin and third-generation cephalosporins were risk factors for C difficile-associated diarrhea after controlling for horizontal transmission. First-generation cephalosporins were not risk factors (OR = 0.86), while sample size considerations prevented firm conclusions about second-generation cephalosporins (OR = 1.67, p = .23). Many of the previously alleged risk factors might be explained by the horizontal transmission of an infectious disease; for instance, this seems a better explanation for an outbreak on a surgery ward than does surgery itself.