Meta-analysis: non-pathogenic yeast Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea

BACKGROUND: Antibiotic-associated diarrhoea occurs in up to 30% of patients who receive antibiotics but can be prevented with probiotics. AIM: To systematically evaluate the effectiveness of Saccharomyces boulardii in preventing antibiotic-associated diarrhoea in children and adults. METHODS: Using medical subject headings and free-language terms, the following electronic databases were searched for studies relevant to antibiotic-associated diarrhoea and S. boulardii: MEDLINE, EMBASE, CINAHL and The Cochrane Library. Additional sources were obtained from references in reviewed articles. Only randomized-controlled trials were considered for study inclusion. RESULTS: Of 16 potentially relevant clinical trials identified, five randomized-controlled trials (1076 participants) met the inclusion criteria for this systematic review. Treatment with S. boulardii compared with placebo reduced the risk of antibiotic-associated diarrhoea from 17.2% to 6.7% (RR: 0.43; 95% CI: 0.23-0.78; random effect model). The number needed to treat to prevent one case of antibiotic-associated diarrhoea was 10 (95% CI: 7-16). No side-effects were reported. CONCLUSIONS: A meta-analysis of data from five randomized-controlled trials showed that S. boulardii is moderately effective in preventing antibiotic-associated diarrhoea in children and adults treated with antibiotics for any reason (mainly respiratory tract infections). For every 10 patients receiving daily S. boulardii with antibiotics, one fewer will develop antibiotic-associated diarrhoea.     

Meta-analysis: Smectite in the treatment of acute infectious diarrhoea in children

BACKGROUND: Although not currently recommended, dioctahedral smectite (smectite) is commonly used to treat acute infectious diarrhoea in many countries. AIM: To evaluate systematically the effectiveness of smectite in treating acute infectious diarrhoea in children. METHODS: Using medical subject headings and free-language terms, the following electronic databases were searched for studies relevant to acute infectious diarrhoea and smectite: MEDLINE, EMBASE, CINAHL and The Cochrane Library; additional references were obtained from reviewed articles. Only randomized-controlled trials were included. RESULTS: Nine randomized-controlled trials (1238 participants) met the inclusion criteria. Combined data from six randomized-controlled trials showed that smectite significantly reduced the duration of diarrhoea compared with placebo. The pooled weighted mean difference was (-22.7 h, 95% CI: -24.8 to -20.6) with a fixed model and remained significant in a random effect model (-24.4 h, 95% CI: -29.8 to -19.1). The chance of cure on intervention day 3 was significantly increased in the smectite vs. the control group (RR 1.64, 95% CI: 1.36-1.98; number needed to treat 4, 95% CI: 3-5). Adverse effects were similar in both groups. CONCLUSIONS: Smectite may be a useful adjunct to rehydration therapy in treating acute paediatric gastroenteritis. However, the results of this meta-analysis should be interpreted with caution as most of the included studies had important limitations. Cost-effectiveness analyses should be undertaken before routine pharmacological therapy with smectite is recommended.     

Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea in children: a randomized double-blind placebo-controlled trial

BACKGROUND: Co-treatment with Saccharomyces boulardii appears to lower the risk of antibiotic-associated diarrhoea in adults receiving broad-spectrum antibiotics. AIM: To determine whether S. boulardii prevents antibiotic-associated diarrhoea in children. METHODS: A total of 269 children (aged 6 months to 14 years) with otitis media and/or respiratory tract infections were enrolled in a double-blind, randomized placebo-controlled trial in which they received standard antibiotic treatment plus 250 mg of S. boulardii (experimental group, n = 132) or a placebo (control group, n = 137) orally twice daily for the duration of antibiotic treatment. Analyses were based on allocated treatment and included data from 246 children. RESULTS: Patients receiving S. boulardii had a lower prevalence of diarrhoea (> or =3 loose or watery stools/day for > or =48 h occurring during or up to 2 weeks after the antibiotic therapy) than those receiving placebo [nine of 119 (8%) vs. 29 of 127 (23%), relative risk: 0.3, 95% confidence interval: 0.2-0.7]. S. boulardii also reduced the risk of antibiotic-associated diarrhoea (diarrhoea caused by Clostridium difficile or otherwise unexplained diarrhoea) compared with placebo [four of 119 (3.4%) vs. 22 of 127 (17.3%), relative risk: 0.2; 95% confidence interval: 0.07-0.5]. No adverse events were observed. CONCLUSION: This is the first randomized-controlled trial evidence that S. boulardii effectively reduces the risk of antibiotic-associated diarrhoea in children.     

Meta-analysis: Lactobacillus GG for treating acute diarrhoea in children

AIM: To review evidence for the effectiveness of Lactobacillus GG (LGG) in treating acute infectious diarrhoea in children. METHODS: The following electronic databases were searched through August 2006 for studies relevant to acute infectious diarrhoea and LGG: MEDLINE, EMBASE, CINAHL and The Cochrane Library; additional references were obtained from reviewed articles. Only randomized-controlled trials (RCTs) were included. RESULTS: Eight RCTs (988 participants) met the inclusion criteria. Compared with controls, LGG had no effect on the total stool volume (two RCTs, n = 303). However, LGG was associated with a significant reduction in diarrhoea duration (seven RCTs, 876 infants, weighted mean difference, WMD -1.1 days (95% confidence interval, CI -1.9 to -0.3), particularly of rotavirus etiology (WMD -2.1 days, 95% CI -3.6 to -0.6), risk of diarrhoea >7 days (one RCT, n = 287, relative risk 0.25, 95% CI 0.09-0.75) and duration of hospitalization (three RCTs, n = 535, WMD -0.58, 95% CI -0.8 to -0.4; significance was lost in the random effect model). There was no reduction in the number of stools at any time interval. CONCLUSIONS: The use of LGG is associated with moderate clinical benefits in the treatment of acute diarrhoea in children. These findings should be interpreted with caution due to the important methodological limitations and heterogeneity of most of the studies.     

Systematic review: racecadotril in the treatment of acute diarrhoea in children

BACKGROUND: Racecadotril (acetorphan) is an antisecretory drug that exerts its antidiarrhoeal effects by inhibiting intestinal enkephalinase. AIM: To summarize studies testing the efficacy and safety of racecadotril for treating children with acute gastroenteritis. METHODS: Reports were gathered by searching electronic databases MEDLINE, EMBASE, the Cochrane Library (all up to April 2007), relevant journals, and bibliographies of reviewed articles. Only randomized-controlled trials were included. RESULTS: Three randomized-controlled trials (471 participants) met the inclusion criteria. Two trials reported stool output, and data suggested less stool output in the racecadotril group than in the control group. The duration of diarrhoea was significantly reduced in the three trials reporting this outcome. Achievement of a cure by day 5 was similar in both groups. Adverse effects were similar in both groups. CONCLUSIONS: The small number of included trials provided some evidence in favour of the use of racecadotril over placebo or no intervention, to reduce the stool output and duration of diarrhoea in children with acute gastroenteritis. However, more data in out-patients are needed. The safety as well as the cost-effectiveness of the therapy should be explored, before routine therapy with racecadotril is recommended.     

Meta-analysis: ondansetron for vomiting in acute gastroenteritis in children

BACKGROUND: Vomiting is a common sympton in children with gastroenteritis, but its treatment remains controversial. AIM: To investigate potential beneficial effects of ondansetron, compared with placebo or no intervention, in treating vomiting during acute gastroenteritis in children. METHODS: The following electronic databases were searched through August 2006: MEDLINE, EMBASE, CINAHL and The Cochrane Library; additional references were obtained from reviewed articles. Only randomized-controlled trials (RCTs) were included. RESULTS: Four RCTs involving 490 patients with vomiting during acute gastroenteritis were included. Combined data from three RCTs (n = 466) showed that ondansetron compared with the control significantly increased the chance for vomiting cessation soon after drug administration [relative risk (RR): 1.3, 95% confidence interval (CI): 1.2-1.5, number needed to treat (NNT): 5, 95% CI: 4-8], but this effect was not observed at 24 h (three RCTs, n = 144, RR 1.2, 95% CI: 0.9-1.7). Ondansetron significantly reduced the risk of intravenous rehydration (two RCTs, n = 359, RR 0.4, 95% CI: 0.3-0.7, NNT 7, 95% CI: 5-14). Outcome measures not significantly different after ondansetron treatment were the need for hospitalization and return emergency department visits. CONCLUSIONS: Despite some clinical benefits, there is insufficient evidence to recommend the routine use of ondansetron for vomiting during acute gastroenteritis in children.     

Systematic review and meta-analysis: the clinical and physiological effects of fibre-containing enteral formulae

Background  Enteral nutrition can be associated with gastrointestinal side effects and fibre supplementation has been proposed as a means to normalize bowel function.
Aim  To evaluate systematically the effects of fibre supplementation of enteral feeds in healthy volunteers and patients both in the hospital and community settings.
Methods  Electronic and manual bibliographic searches were conducted. Controlled studies in adults or children, comparing fibre-supplemented vs. fibre-free formulae given as the sole source of nutrition for at least 3 days, were included.
Results  Fifty-one studies (including 43 randomized-controlled trials), enrolling 1762 subjects (1591 patients and 171 healthy volunteers) met the inclusion criteria. Fibre supplementation was generally well tolerated. In the hospital setting, the incidence of diarrhoea was reduced as a result of fibre administration (OR 0.68, 95% CI: 0.48–0.96; 13 randomized-controlled trials). Meta-regression showed a more pronounced effect when the baseline incidence of diarrhoea was high. In both patients and healthy subjects, fibre significantly reduced bowel frequency when baseline frequency was high and increased it when it was low, revealing a significant moderating effect of fibre.
Conclusions  The review indicates that the fibre-supplemented enteral formulae have important physiological effects and clinical benefits. There is a need to use a consistent approach to undertake more studies on this issue in the community setting.     

布拉酵母菌散治疗新生儿黄疸Meta分析

目的:系统评价布拉酵母菌散治疗新生儿黄疸的疗效,为临床提供循证参考。方法:计算机检索Cochrane图书馆、PubMed、EMBASE、Cochrane对照试验中心数据库、中国生物医学文献数据库、中国期刊全文数据库、中国科技期刊全文数据库、万方数据库,全面收集布拉酵母菌散(试验组)与常规治疗(对照组)治疗新生儿黄疸的随机对照试验(RCT),对符合纳入标准的研究提取资料并进行质量评价后,采用Cochrane RevMan5.1统计软件进行Meta分析。结果:本次统计共纳入11篇文献,合计1 217例患儿。Meta分析结果显示,试验组总有效率[RR=1.11,95% CI(1.05,1.17),I2=0%]、黄疸消退时间[MD=1.78,95% CI(-2.29,-1.26),I2=93%]、日均胆红素下降值[MD=12.80,95% CI(8.23,17.37),I2=43%] 均优于对照组(P均<0.01)。11篇文献中,1篇文献报道两组患儿治疗后不良反应(ADR)发生率比较差异无统计学意义,2篇文献报道两组未发生ADR,8篇文献未报道ADR情况。结论:基于当前的研究证据,布拉酵母菌散能有效辅助治疗新生儿黄疸,未发现明显不良反应,但因国内外均缺乏高质量的RCT研究,故布拉酵母菌散治疗新生儿黄疸的疗效和安全性尚需进一步评价。     

布拉酵母菌预防儿童抗生素相关性腹泻疗效的Meta分析

目的：探讨布拉酵母茵与儿童抗生素相关性腹泻（AAD）的关系,分析布拉酵母茵预防儿童AAD的有效性及安全性。方法：检索PubMed、Embase．CDSR、CNKI和VIP数据库,收集布拉酵母菌预防儿童AAD的临床试验文献,采用RevMan5．0软件进行Meta分析。结果：共纳入9篇临床试验文献,1511例病例,Meta分析结果显示,RR（95％CI）为0．49（0．41～0．58）（P〈0．001）,未见不良反应报道。结论：布拉酵母菌可以显著降低儿童AAD发生。     

布拉氏酵母菌治疗小儿急性腹泻病的临床研究

目的:评估布拉氏酵母茵散剂治疗小儿急性腹泻病的临床疗效.方法:以我院2008年3月～6月收治的92例小儿急性腹泻病惠儿为研究对象,随机分成两组各46例.两组均予补液、蒙脱石散剂口服、抗生素治疗,治疗组加服布拉氏酵母菌散剂连续治疗至出院,对92例惠儿资料进行数据分析.结果:两组总有效率比较差异有统计学意(X2=4.84,P＜0.05).腹泻平均持续时间对照组为(6.54±1.74)d,治疗组为(5.72±1.67)d(t=2.30,P＜0.05),两组比较差异有统计学意义;服药第4 d治疗组日平均大便次数(3.13±0.95)次,对照组(3.74±0.91)次(t=3.14,P＜0.01),服药第7 d治疗组日平均大便次数(1.74±0.93)次,对照组(2.24±0.95)次(t=2.55,P＜0.05),两组比较差异均有统计学意义;治疗组按给药治疗时机进行分层分析,比较第4 d和第7 d大便次数(t分别为3.90、3.71,P均＜0.01),差异有统计学意义.结论:布拉氏酵母茵可缩短小儿急性腹泻的持续时间,促进患儿恢复,患儿在腹泻发生48 h内早期给予布拉氏酵母茵治疗效果更佳.     

Systematic review and meta-analysis: proton-pump inhibitor treatment for ulcer bleeding reduces transfusion requirements and hospital stay--results from the Cochrane Collaboration

BACKGROUND: Proton-pump inhibitors reduce re-bleeding and surgical intervention, but not mortality, after ulcer bleeding. AIM: To examine the effects of proton-pump inhibitor treatment on transfusion requirements and length of hospital stay in patients with ulcer bleeding. METHODS: For the Cochrane Collaboration meta-analysis of randomized-controlled trials of proton-pump inhibitor therapy for ulcer bleeding, outcomes of transfusion requirements and hospital stay were summarized, respectively, as mean (+/-s.d.) units transfused and hospital days. We calculated weighted mean difference with 95% confidence interval. We also performed subgroup analyses according to geographical origin of the randomized-controlled trials. RESULTS: There was significant heterogeneity among randomized-controlled trials for either outcome. Overall, proton-pump inhibitor treatment marginally reduced transfusion requirements (WMD = -0.6 units; 95% CI: -1.1 to 0; P = 0.05) and length of hospitalization (WMD = -1.1 days; 95% CI: -1.5 to -0.7; P < 0.0001). Most of the randomized-controlled trials did not state precise criteria for administering blood transfusion and discharging patients, thereby limiting the strength of conclusions on the pooled effects. CONCLUSIONS: Proton-pump inhibitor treatment for ulcer bleeding produces small, but potentially important, reductions in transfusion requirements and length of hospitalization.     

布拉氏酵母菌联合标准三联疗法根治幽门螺杆菌感染的meta分析

目的 系统评价布拉氏酵母菌联合标准三联疗法根治幽门螺杆菌感染的疗效与安全性.方法 通过检索PubMed、EMBASE、Cochrane Central Register of Controlled Trials、MEDLINE等数据库1982年1月至2011年12月相关文献,全面收集应用布拉氏酵母菌联合标准三联疗法治疗Hp感染的随机对照试验,并用RevMan 5.0.2软件进行meta分析.结果 纳入5个试验包括1307例患者.其中4项试验的数据显示,与对照组相比,布拉氏酵母菌联合标准三联疗法能显著提高Hp根除率(n=915,OR=1.66,95％C1:1.22～1.26,P=0.001);有效降低三联疗法相关性不良反应(n=1305,OR=0.32,95％CI:0.17～0.63,P=0.008),特别是腹泻的发生率(4项试验,n=1215,OR=0.42,95％CI:0.27～0.64,P＜0.0001);但2组间的其他不良反应发生率无显著性差异.结论 布拉氏酵母菌联合标准三联疗法可显著性提高Hp感染的根治率,降低三联疗法总体相关性不良反应,特别是腹泻发生率.     

布拉氏酵母菌治疗小儿急性腹泻的临床研究

目的：探讨布拉氏酵母菌治疗小儿急性腹泻的临床疗效。方法对本院收治2012年5月-10月的90例小儿急性腹泻患儿的临床资料进行回顾性分析,根据用药方法不同分为观察组和对照组,对照组患儿给予益生菌、补锌剂、蒙脱石散剂口服及补液等常规治疗,观察组在对照组治疗基础上加用布拉氏酵母菌散剂治疗。对两组的临床疗效、止泻时间情况进行对比分析。结果观察组有效率明显高于对照组（P〈0.01）;两组患儿在治疗后3d平均大便次数均较治疗前明显降低,且观察组改善更加明显（P〈0.05）;治疗后7 d,两组患儿平均大便次数比较,差异无统计学意义（P〉0.05）;观察组平均止泻时间明显少于对照组（P〈0.05）。结论使用布拉氏酵母菌能有效提高临床疗效,减少大便次数,缩短腹泻持续时间。     

布拉氏酵母菌佐治儿童细菌性肠炎疗效观察

目的:探讨布拉氏酵母菌佐治儿童细菌性肠炎中的临床疗效。方法:以湖北省医药学院附属人民医院2010年9月至2011年12月收治的98例细菌性肠炎患儿为研究对象,随机分成治疗组和对照组各49例。两组均给予抗感染、补液、对症治疗,治疗组在上述治疗的基础上同时口服布拉氏酵母菌散剂250 mg,每天2次治疗至治愈出院,比较两组症状体征恢复情况及临床疗效,观察不良反应。结果:治疗组总有效率100.0%,对照组总有效率88.6%,两组比较差异有统计学意义(P<0.05)。腹泻平均持续时间分别为治疗组(5.9±1.1)d,对照组(7.9±1.8)d,两组比较差异有统计学意义(P<0.05);入院后第5天平均大便次数比较,治疗组(2.5±0.8)次,对照组(3.9±1.2)次,第7天平均大便次数分别为治疗组(1.2±0.4)次,对照组(2.3±0.8)次,两组比较差异均有统计学意义(P<0.01)。结论:布拉氏酵母菌可缩短儿童细菌性肠炎的腹泻持续时间,减少腹泻次数。     

Review article: the use of biotherapeutic agents in the prevention and treatment of gastrointestinal disease

There is presently a lack of well conducted clinical trials demonstrating any significant benefits of probiotics in humans. With the exception of diarrhoea due to rotavirus infection in children there is little evidence from randomized, double-blind, placebo-controlled studies that bacterial probiotics have a significant beneficial action in preventing diarrhoea of any cause. The yeast Saccharomyces boulardii has been shown to be of benefit in the prevention of antibiotic-associated diarrhoea but not in preventing infection with Clostridium difficile . S. boulardii may also be of benefit in preventing relapse of C. difficile infection. Because of the simplicity of in vitro systems and some animal models, beneficial characteristics of probiotics such as the ability of bacteria to bind to epithelial surfaces are not always transferable to humans. Thus any postulated benefit from consumption of probiotic bacteria should only be accepted as fact after testing in clinical studies.
This review outlines our present knowledge of the mode of action of probiotics and presents the data from clinical trials on their use.     

Meta-analysis: zinc supplementation for acute gastroenteritis in children

Background  Uncertainty exists regarding the use of zinc in the treatment of acute gastroenteritis in children living in Europe, where zinc deficiency is rare.
Aim  To review evidence for the effectiveness of zinc in treating acute gastroenteritis in children, with special emphasis on data from developed countries.
Methods  MEDLINE, EMBASE, and the Cochrane Library were searched through November 2007 for randomized controlled trials (RCTs) relevant to acute gastroenteritis in children younger than 5 years of age and zinc; additional references were obtained from the reviewed articles.
Results  Eighteen RCTs (11 180 participants, mainly from developing countries) met the inclusion criteria. Use of zinc was associated with a significant reduction in diarrhoea duration (13 RCTs, 5643 infants, weighted mean difference −0.69 day, 95% CI −0.97 to −0.40) and the risk of diarrhoea lasting longer than 7 days [eight RCTs, n  = 5769, relative risk (RR) 0.71, 95% CI 0.53–0.96]. No significant reduction in stool volume was observed for those receiving zinc compared with placebo (three RCTs, n  = 606, standardized mean difference, −0.38, 95% CI −1.04 to 0.27). Combined data from five RCTs ( n  = 3156) showed that zinc significantly increased the chance of vomiting compared to the control agent (RR 1.2, 95% CI 1.05–1.4).
Conclusions  These data confirm that zinc supplementation can be useful for treating acute gastroenteritis in children, particularly those from developing countries. However, the role of zinc supplements in treating children with acute gastroenteritis in developed countries needs further evaluation.     

布拉氏酵母菌在治疗儿童急性腹泻中的作用评价

目的评价布拉氏酵母菌在治疗儿童急性腹泻中的作用及安全性。方法将120例急性腹泻患者随机分为2组,每组60例,对照组采用双歧杆菌三联活菌散加双八面体蒙脱石,治疗组采用布拉酵母菌,观察其疗效。结果两组在治疗后48 h大便好转数、治疗后72 h痊愈数、治疗5 d后大便减少次数、止泻时间、病程<7 d比率方面效果相当(P>0.05)。结论布拉氏酵母菌治疗急性腹泻的疗效等同于双歧杆菌三联活菌散加双八面体蒙脱石,并且未观察到不良反应。     

Meta-analysis: the effects of Lactobacillus rhamnosus GG supplementation for the prevention of healthcare-associated diarrhoea in children

Aliment Pharmacol Ther 2011; 34: 1079–1087

Summary

Background In children, healthcare‐associated diarrhoea, in particular, due to rotavirus, may prolong the hospital stay and increase medical costs, prompting interest in effective, low‐cost, preventive strategies. Aim To review systematically data on the efficacy of administering Lactobacillus rhamnosus GG (LGG) for the prevention of healthcare‐associated diarrhoea. Methods MEDLINE, EMBASE, Health Source: Nursing/Academic Edition, the Cochrane Library, trial registries and proceedings of major meetings were systematically searched for randomised controlled trials (RCTs) performed in children aged 1 month to 18 years that compared administration of LGG with placebo or no intervention. Two reviewers assessed studies for inclusion and risk of bias and extracted the data. Outcome measures included the incidences of healthcare‐associated diarrhoea and rotavirus gastroenteritis. If appropriate, meta‐analyses were carried out using the fixed effects model. Results Three RCTs involving 1092 children were included. Compared with placebo, LGG administration for the duration of hospital stay was associated with significantly lower rates of diarrhoea (two RCTs, n = 823, relative risk, RR 0.37, 95% confidence interval, CI 0.23–0.59) and symptomatic rotavirus gastroenteritis (three RCTs, n = 1043, RR 0.49, 95% CI 0.28–0.86). There was no significant difference between the LGG and the control groups in the incidence of asymptomatic rotavirus infection, duration of hospitalisation or duration of diarrhoea. LGG was well tolerated, and no harms were reported in any of the trials. Conclusion In hospitalised children, the administration of Lactobacillus rhamnosus GG compared with placebo has the potential to reduce the overall incidence of healthcare‐associated diarrhoea, including rotavirus gastroenteritis.     

Review article: yeast as probiotics -- Saccharomyces boulardii

BACKGROUND: Probiotics are defined as live micro-organisms which confer a health benefit on the host. Although most probiotics are bacteria, one strain of yeast, Saccharomyces boulardii, has been found to be an effective probiotic in double-blind clinical studies. AIMS: To compare the main properties that differentiates yeast from bacteria and to review the properties of S. boulardii explaining its potential benefits as a probiotic. METHODS: The PubMed and Medline databases were searched using the keywords 'probiotics', 'yeast', 'antibiotic associated diarrhea', 'Saccharomyces boulardii','bacterial diarrhea' and 'inflammatory bowel disease' in various combinations. RESULTS: Several clinical studies have been conducted with S. boulardii in the treatment and prevention of various forms of diarrhoea. Promising research perspectives have been opened in terms of maintenance treatment of inflammatory bowel diseases. The mechanism of S. boulardii's action has been partially elucidated. CONCLUSION: Saccharomyces boulardii is a strain of yeast which has been extensively studied for its probiotic effects. The clinical activity of S. boulardii is especially relevant to antibiotic-associated diarrhoea and recurrent Clostridium difficile intestinal infections. Experimental studies clearly demonstrate that S. boulardii has specific probiotic properties, and recent data has opened the door for new therapeutic uses of this yeast as an 'immunobiotic'.     

Behaviour of Saccharomyces boulardii in recurrent Clostridium difficile disease patients

BACKGROUND: Despite recent interest in therapeutic microorganisms taken orally, little is known about the pharmacodynamics of these agents in a target population of patients with disease. The present study reports the stool concentrations of Saccharomyces boulardii in a patient population with Clostridium difficile disease (CDD) and correlates stool concentrations with efficacy. METHODS: Patients with recurrent CDD all received a 10-day standard antibiotic regimen together with 28 days of S. boulardii or placebo. Stool samples were collected from patients at various time points and assayed for S. boulardii. RESULTS: The mean concentration of S. boulardii of patients who recurred was 2.5 x 104 CFU/g compared to 1 x 106 CFU/g in patients that did not recur (P=0.02). Patients with low yeast concentrations in their stools (<104/g) recurred more often (14/15, 93%) compared with patients with higher levels (19/35, 54%, P=0.007). Clearance of S. boulardii was rapid; only 4% had positive stools 3 days after stopping dosing. CONCLUSIONS: After chronic dosing of S. boulardii, patients with low stool concentrations had a higher likelihood of recurrence of CDD. Stool concentrations were also lower during periods of diarrhoea. These results show the importance of characterizing the dynamics of a therapeutic microorganism in patients with disease, as kinetic studies in healthy volunteers may not give a true reflection of the disturbed microecology in the disease state.