难辨梭菌鉴定培养基临床应用评估

目的评估难辨梭菌鉴定培养基(CDIF)的应用价值。方法用方法学评估研究。对临床收集的255份粪便标本同步进行CDIF培养基和环丝氨酸-头孢西丁-果糖琼脂培养基(CCFA)培养,并对CDIF培养基上的所有菌株及CCFA培养基上的典型菌株进行基质辅助激光解吸/电离飞行时间质谱鉴定。结果 255份粪便标本中,经CDIF培养24 h后出现典型菌株64株,经质谱鉴定为难辨梭菌58株;另有3株无色透明菌落的菌株被质谱鉴定为难辨梭菌。以质谱鉴定结果为参考,CDIF培养基对难辨梭菌鉴定的敏感性、特异性、阳性预测值、阴性预测值分别为95.1%(58/61)、96.9%(188/194)、90.6%(58/64)和98.4%(188/191)。CCFA培养48 h后生长的典型菌株经质谱鉴定为难辨梭菌61株。CDIF培养基和CCFA培养基上经质谱鉴定为难辨梭菌的菌落中,分离单一菌种比例分别为80.3%(49/61)和77.0%(47/61);CDIF培养基上菌落生长密度高于CCFA培养基。结论 CDIF培养基具有快速准确、操作简便、成本较低的特点,为难辨梭菌感染的实验室诊断提供了新的选择。     

粪菌移植在儿科应用的研究进展北大核心CSCD

粪菌移植(FMT)可将健康人粪便中的各种肠道微生物、代谢产物和天然抗菌物质等移植到受者肠道内,可重建肠道菌群平衡、修复肠黏膜屏障、控制炎症反应、调节机体免疫,是治疗肠道菌群失调所致疾病的新方法。FMT治疗儿童复发性艰难梭菌感染已写入复发性艰难梭菌感染的诊疗指南。FMT治疗儿童炎症性肠病、孤独症谱系障碍的有效性及安全性较好。     

Recent Insights into Clostridium perfringens Beta-Toxin

Clostridium perfringens beta-toxin is a key mediator of necrotizing enterocolitis and enterotoxemia. It is a pore-forming toxin (PFT) that exerts cytotoxic effect. Experimental investigation using piglet and rabbit intestinal loop models and a mouse infection model apparently showed that beta-toxin is the important pathogenic factor of the organisms. The toxin caused the swelling and disruption of HL-60 cells and formed a functional pore in the lipid raft microdomains of sensitive cells. These findings represent significant progress in the characterization of the toxin with knowledge on its biological features, mechanism of action and structure-function having been accumulated. Our aims here are to review the current progresses in our comprehension of the virulence of C. perfringens type C and the character, biological feature and structure-function of beta-toxin.     

Evaluating Epidemiology and Improving Surveillance of Infections Associated with Health Care,United States

The Healthcare-Associated Infections Community Interface (HAIC), launched in 2009, is the newest major activity of the Emerging Infections Program. The HAIC activity addresses population- and laboratory-based surveillance for Clostridium difficile infections, candidemia, and multidrug-resistant gram-negative bacilli. Other activities include special projects: the multistate Healthcare-Associated Infections and Antimicrobial Use Prevalence Survey and projects that evaluate new approaches for improving surveillance. The HAIC activity has provided information about the epidemiology and adverse health outcomes of health care–associated infections and antimicrobial drug use in the United States and informs efforts to improve patient safety through prevention of these infections.     

The Effect of Lactobacillus plantarum 299v on the Incidence of Clostridium difficile Infection in High Risk Patients Treated with Antibiotics

Background: Lactobacillus plantarum 299v (LP299v) has been used in order to reduce gastrointestinal symptoms during antibiotic exposure. However, it remains controversial whether or not probiotics are effective in the prevention of Clostridium difficile infections (CDI) among patients receiving antibiotics. The aim of this study was to analyze the CDI among patients receiving antibiotics and hospitalized in the period before and after starting routine use of LP299v as a prevention of this infection. Methods: Among 3533 patients hospitalized in the nephrology and transplantation ward during a two-year period, 23 patients with CDI were diagnosed and enrolled in this retrospective study. Since November 2013, prevention of CDI with oral use of LP299v was performed in all patients treated with antibiotics and who were at a high risk of developing CDI. The observation period was divided into two twelve-month intervals before and after initiation of the use of LP299v as a prophylactic against CDI. Results: A significant (p = 0.0001) reduction of the number of cases of CDI was found after routinely using LP299v (n = 2; 0.11% of all hospitalized patients) compared with the previous twelve-month period of observation (n = 21; 1.21% of all hospitalized patients). Conclusions: Routine use of LP299v during treatment with antibiotics may prevent C. difficile infection in the nephrology and transplantation ward.     

The yield of stool testing in hospital-onset diarrhea: Has evidence changed practice?

Introduction: Aside from examination for Clostridium difficile, the yield of stool testing in hospital-onset diarrhea is poor. Clinical practice guidelines discourage overzealous stool testing in patients with diarrhea that develops after the third hospital day. However, the adoption of this recommendation into clinical practice is limited. Furthermore, the effect of microbiology laboratory improvements on hospital-onset diarrhea testing is largely unknown. Methods: A retrospective cohort study was conducted in a university-affiliated community-hospital and included all adult inpatients who developed diarrhea after hospitalization. Results: 132 adult patients (53% female) developed diarrhea after hospitalization in 2013. The cohort’s mean age was 55.6 years. 46.2% of patients developed diarrhea in the first 3 days of hospitalization. Testing for parasites was negative in all examined 67 samples. Testing for C. difficile was positive in 13 cases (10.8%) out of 120 tested samples. Testing for other pathogens was positive in 1 sample (Campylobacter) out of 129 samples. Stool samples tested in the first 3 days of hospitalization were more likely to be positive (64.3 vs 35.7%, p = 0.1). Change in management was reported in 9 out of 14 patients (64.3%) with positive stool testing compared with 31 out of 118 patients (26.3%) with negative stool testing, p = 0.01. Conclusion: Despite improvements in stool samples’ testing, the yield continues to be low, especially in hospital-onset diarrhea past the third hospital day. Physicians’ embracement of the ‘3-day rule’ continues to be poor.     

Clostridium perfringens enterotoxin C‐terminal domain labeled to fluorescent dyes for in vivo visualization of micrometastatic chemotherapy‐resistant ovarian cancer

Identification of micrometastatic disease at the time of surgery remains extremely challenging in ovarian cancer patients. We used fluorescence microscopy, an in vivo imaging system and a fluorescence stereo microscope to evaluate fluorescence distribution in Claudin‐3‐ and ‐4‐overexpressing ovarian tumors, floating tumor clumps isolated from ascites and healthy organs. To do so, mice harboring chemotherapy‐naïve and chemotherapy‐resistant human ovarian cancer xenografts or patient‐derived xenografts (PDXs) were treated with the carboxyl‐terminal binding domain of the Clostridium perfringens enterotoxin (c‐CPE) conjugated to FITC (FITC‐c‐CPE) or the near‐infrared (NIR) fluorescent tag IRDye CW800 (CW800‐c‐CPE) either intraperitoneally (IP) or intravenously (IV). We found tumor fluorescence to plateau at 30 min after IP injection of both the FITC‐c‐CPE and the CW800‐c‐CPE peptides and to be significantly higher than in healthy organs (p < 0.01). After IV injection of CW800‐c‐CPE, tumor fluorescence plateaued at 6 hr while the most favorable tumor‐to‐background fluorescence ratio (TBR) was found at 48 hr in both mouse models. Importantly, fluorescent c‐CPE was highly sensitive for the in vivo visualization of peritoneal micrometastatic tumor implants and the identification of ovarian tumor spheroids floating in malignant ascites that were otherwise not detectable by conventional visual observation. The use of the fluorescent c‐CPE peptide may represent a novel and effective optical approach at the time of primary debulking surgery for the real‐time detection of micrometastatic ovarian disease overexpressing the Claudin‐3 and ‐4 receptors or the identification of residual disease at the time of interval debulking surgery after neoadjuvant chemotherapy treatment.     

粪菌移植在炎症性肠病中的治疗进展

炎症性肠病(IBD)是肠道慢性、复发性自身免疫性疾病,是由遗传易感的宿主对肠道菌群异常的免疫反应所致。近年来,肠道菌群与IBD患病的关系倍受关注。粪菌移植(FMT)是将健康人肠道菌群移植至病人的胃肠道内,重建具有正常功能的肠道菌群。许多研究结果表明,FMT在IBD治疗中有效。以下就国内外FMT中心发表的FMT在IBD病人中治疗进展作一综述。