Probiotic therapy for the prevention and treatment of Clostridium difficile-associated diarrhea: a systematic review

Enteritis and colitis in horses

Enteritis and colitis remain challenging and life-threatening diseases despite many recent advances. Successful treatment is largely dependent on early recognition and directed therapy, which is facilitated by obtaining a complete history and physical examination. A number of new therapies and methods of monitoring critically ill patients have become integral components of treatment success. The critical monitoring of equine foals and adults continues to be an exciting and emerging field.

Clinical management of Clostridium difficile-associated disease

The incidence of Clostridium difficile-associated disease (CDAD) and its serious complications (including colectomy and death) have been increasing worldwide. This phenomenon is strongly associated with the appearance of a new "hypervirulent" strain in several countries. More-effective strategies are needed for the prevention and treatment of this entity. This article will review the current approaches using antimicrobials, probiotics, immunomodulation, surgery, and miscellaneous adjuvants to prevent and treat this infection.

Antibiotic-associated diarrhoea

Diarrhoea is a common complication of antimicrobial therapy. The term antibiotic-associated diarrhoea (AAD) is often considered synonymous with Clostridium difficile. In fact, AAD can develop through a variety of mechanisms and manifest through a broad range of clinical signs and symptoms. For improved prevention and recognition of AAD, it is important to understand the pathophysiology and risk factors for AAD. Although Clostridium difficile continues to be the most common identifiable pathogen of AAD, many patients with AAD can be managed through a variety of conservative measures. This review focuses on some of the important distinctions between nonspecific AAD and antibiotic-associated colitis. In addition, the most recent data on important risk factors for the development of AAD are summarised. Given its pathogenicity, there will be an emphasis on the early diagnosis, treatment and prevention of Clostridium difficile-associated diarrhoea. AAD is a common clinical problem that can progress to severe, life-threatening disease if not recognised quickly. Better awareness of risk factors can lead to the most efficacious treatment of this disorder: primary prevention.

Colonization and impact of disease and other factors on intestinal microbiota

The aim of this study was to review the process of microbial colonization and the environmental and host factors that influence colonization and microbial succession. The impact of some diseases on intestinal microbiota composition is also described. Microbial colonization of the gut by maternal vaginal and fecal bacteria begins during and after birth. During the first 2 years of life, specific microbes become established in a process designated microbial succession. Microbial succession in the gastrointestinal tract is influenced by numerous external and internal host-related factors, and by the second year of life, the intestinal microbiota composition is considered identical to that of adults. Nevertheless, intestinal microbiota in both infants and adults remain incompletely characterized and their diversity poorly defined. The main explanation is that many intestinal bacteria that live in an anaerobic environment are difficult or impossible to culture outside the intestine. However, recent advances in molecular biology techniques have initiated the description of new bacteria species. The composition of gut microbiota can be modulated by host, environmental, and bacterial factors, and strong evidence has emerged of substantial modifications during illness or exposure to threatening experiences. It has been postulated that improvements in hygienic measures have led to an increase in allergic diseases ("hygiene hypothesis"). Alterations in gut microbiota and their functions have been widely associated with many chronic and degenerative diseases, including inflammatory bowel disease, colon cancer, and rheumatoid arthritis.

Clostridium difficile—Associated Diarrhea, an Emerging Epidemic: Therapeutic Options

Clostridum difficile—associated disease (CDAD) is the leading cause of infectious diarrhea and is associated with considerable morbidity and mortality. The incidence is estimated to range from 3.4 to 8.4 cases per 1000 hospital admissions, and it has become a growing problem at many institutions. Treatment options for CDAD are limited due to a paucity of new pharmacologic agents and studies examining other potential treatments. Historically oral metronidazole and oral vancomycin have been used as first-line agents in the treating CDAD, however recent reports of treatment failure and recurrence with these agents have surfaced. These reports illustrate a need for novel pharmacologic agents and a thorough review of currently available agents that may have activity against C difficile. Available data on the treatment of CDAD were extracted and reviewed to outline the appropriate management of CDAD.

Clostridium difficile-associated disease: changing epidemiology and implications for management

Clostridium difficile-associated disease (CDAD) is increasingly being reported in many regions throughout the world. The reasons for this are unknown, are likely to be multifactorial, and are the subject of several current investigations. In addition to the upsurge in frequency of CDAD, an increased rate of relapse/recurrence, disease severity and refractoriness to traditional treatment have also been noted. Moreover, severe disease has been reported in non-traditional hosts (e.g. younger age, seemingly healthy, non-institutionalised individuals residing in the community, and some without apparent antimicrobial exposure). A previously uncommon and more virulent strain of C. difficile has been reported at the centre of multiple transcontinental outbreaks. The appearance of this more virulent strain, in association with certain environmental and antimicrobial exposure factors, may be combining to create the 'perfect storm'. It is human nature to be reactive; however, the successful control of C. difficile will require healthcare systems (including administrators, and leadership within several departments such as environmental services, infection control, infectious diseases, gastroenterology, surgery, microbiology and nursing), clinicians, long-term care and rehabilitation facilities, and patients themselves to be proactive in a collaborative effort. Guidelines for the management of CDAD were last published over a decade ago, with the next iteration due in the fall (autumn) of 2007. Several newer therapies are under investigation but it is unclear whether they will be superior to current treatment options.

The challenges posed by reemerging Clostridium difficile infection

There have been recent, marked increases in the incidence and severity of Clostridium difficile-associated disease (CDAD). These may be attributable to the emergence of a hypervirulent strain of C. difficile that produces increased levels of toxins A and B, as well as an extra toxin known as "binary toxin." This previously uncommon strain has become epidemic, coincident with its development of increased resistance to fluoroquinolones, the use of which is increasingly associated with CDAD outbreaks. Although not necessarily related to this epidemic strain, unusually severe CDAD has been reported in populations that had previously been thought to be at low risk, including peripartum women and healthy persons living in the community. Challenges posed by the changing epidemiology of CDAD are compounded by current limitations in diagnostic testing, treatment, and infection control. Overcoming these challenges and limitations will require a concerted effort from a variety of sources, including an ongoing partnership between infectious disease clinicians and public health professionals.

A case of recurrent Clostridium difficile diarrhea

Clostridium difficile is an important and increasingly common cause of nosocomial diarrhea. Recent epidemics of C. difficile-associated disease (CDAD) reveal a pathogen that is becoming more virulent, leading to an increase in disease severity, treatment failures, and relapses. Those of advanced age are at a particular risk of acquiring this debilitating and costly disease. This case describes CDAD recurring in an 87-year-old resident of a long-term care facility, which caused hospitalization. After five days of therapy on oral metronidazole with minimal improvement in diarrheal symptoms, the patient was switched to oral vancomycin. The patient subsequently improved and completed a 14-day course of metronidazole/vancomycin. The patient's stool was recultured shortly before finishing therapy and revealed C. difficile antigen; the patient was asymptomatic at that time, and it was therefore recommended to stop therapy after the 14-day treatment course. The patient was concurrently prescribed lactobacillus, a probiotic, for treatment of CDAD. The use of probiotics in the treatment of CDAD needs further study.

Probiotics and prebiotics: effects on diarrhea

Probiotics have preventive as well as curative effects on several types of diarrhea of different etiologies. Prevention and therapy (or alleviation) of diarrhea have been successfully investigated for numerous dietary probiotics to establish probiotic properties and to justify health claims (the medicinal use of probiotic food and the therapy of gastrointestinal diseases itself may not be advertised under current food laws). Other probiotic microorganisms (e.g., Lactobacillus rhamnosus GG, L. reuteri, certain strains of L. casei, L. acidophilus, Escherichia coli strain Nissle 1917, and certain bifidobacteria and enterococci (Enterococcus faecium SF68) as well as the probiotic yeast Saccharomyces boulardii have been investigated with regard to their medicinal use, either as single strains or in mixed-culture probiotics. However, the effects on humans have been assessed mainly in smaller (n<100) randomized, controlled clinical studies or in open label trials, but large intervention studies and epidemiological investigations of long-term probiotic effects are largely missing. Perhaps with the exception of nosocomial diarrhea or antibiotic-associated diarrhea, the results of these studies are not yet sufficient to give specific recommendations for the clinical use of probiotics in the treatment of diarrhea.

Prebiotics, probiotics, and dietary fiber in gastrointestinal disease

Microecology of the gastrointestinal tract is the physiologic basis for the effect of dietary fiber, prebiotics and probiotics on the host. The ecology consists of the gastrointestinal tract, primarily the intestines, the foods that are fed into the tract, and the flora living within. Within this ecology, normal flora and probiotics, ferment dietary fiber and prebiotics to produce short chain fatty acids and substances that are absorbed and effect the host at the intestinal level and systemically. In this review, we will discuss the effects of prebiotics, probiotics and dietary fiber in gastrointestinal disorders and diseases.

Probiotics as functional food in the treatment of diarrhea

PURPOSE OF REVIEW

A disturbance in microbial balance of the gastrointestinal tract is often associated with diarrhea. Therefore, probiotics, as beneficial microorganisms for host health, have attracted clinical attention for their potential therapeutic application in the treatment of diarrhea. This review focuses on new research findings relevant to the effects of probiotics on diarrhea prevention and treatment and potential mechanisms of action for this alternative therapy for diarrhea.

RECENT FINDINGS

Clinical trials suggest potential beneficial effects of probiotic therapy for preventing and treating antibiotic-associated diarrhea, acute diarrhea including rotavirus-induced diarrhea, traveler's diarrhea, and diarrhea-predominant irritable bowel syndrome. The most extensively studied probiotics for diarrhea are Lactobacillus, Bifidobacterium and Saccharomyces, with potential mechanisms of therapeutic action based on the protection of intestinal epithelial cell and barrier function, prevention of enterotoxin binding to intestinal epithelial cells, and regulation of intestinal microbial environment.

SUMMARY

Growing evidence suggests that probiotics may serve as a functional food in the treatment of diarrhea. Remaining challenges include identifying mechanisms of action to provide the basis of more refined hypothesis-driven clinical trials. The correct combination and concentration of probiotics applied to the appropriate gastrointestinal disorders may improve the efficacy of this approach for diarrhea and other diseases.

Novel ways of preventing antibiotic-resistant infections: what might the future hold?

Most antibiotic-resistant bacteria are opportunistic pathogens; they colonize the skin and mucosal surfaces and only cause infection when the opportunity arises. Thus, the processes that lead to an infection attributable to antibiotic-resistant bacteria can be broadly divided into those processes that lead to acquisition of antibiotic-resistant bacteria and those that lead to the development of an infection with that organism. We review the processes that lead to the development of infections attributable to antibiotic-resistant bacteria. We then discuss options that may become available to interrupt these processes and, thus, may reduce the rate of infections attributable to antibiotic-resistant bacteria in the future.

Clinical efficacy of probiotics: review of the evidence with focus on children

Probiotics are marketed in several countries and widely used by pediatric health care providers. Although probiotics can be helpful for specific disorders, they have been broadly prescribed for disorders without clear evidence to support their use. Furthermore, in certain specific conditions, probiotics cause clinical deterioration. This report is a review and evaluation of the evidence or lack thereof to support a beneficial effect of probiotic agents in a variety of pediatric conditions and to review the safety and potential adverse events that may be encountered when using probiotics. It is also important to emphasize that probiotics are highly heterogeneous with differences in composition, biological activity, and dose among the different probiotic preparations.

Do probiotics have a therapeutic role in gastroenterology?

Several hundred species of bacteria inhabit the gut, and affect its cell biology, morphology and homeostasis. Many bacteria are however potential pathogens, especially if the integrity of the epithelial barrier is physically or functionally breached. Conversely, the interaction between host and commensal microbes can confer important health benefits. This has led to commercial and public interest in 'probiotics', live microbes principally taken as food supplements. Might probiotics also be used in disease therapy Experimental evidence that probiotics modulate gut physiology, particularly barrier integrity and immunological function, underpins exciting new gastroenterological research. We discuss below the scientific basis for probiotic effects and present a critical perspective for their use in relation to gastrointestinal disease.

Probiotics in the prevention of antibiotic-associated diarrhea in children: a meta-analysis of randomized controlled trials

OBJECTIVE

To systematically evaluate the effectiveness of probiotics in preventing antibiotic-associated diarrhea (AAD) in children.

STUDY DESIGN

The following electronic databases up to December 2005, in any language, were searched for studies relevant to AAD and probiotics: MEDLINE, EMBASE, and The Cochrane Library. Only randomized controlled trials (RCT) were considered for study inclusion.

RESULTS

Six placebo-controlled, RCTs (766 children) were included. Treatment with probiotics compared with placebo reduced the risk of AAD from 28.5% to 11.9% (relative risk, RR, 0.44, 95% CI 0.25 to 0.77, random effect model). Preplanned subgroup analysis showed that reduction of the risk of AAD was associated with the use of Lactobacillus GG (2 RCTs, 307 participants, RR 0.3, 95% CI 0.15 to 0.6), S. boulardii (1 RCT, 246 participants, RR 0.2, 95% CI 0.07-0.6), or B. lactis & Str. thermophilus (1 RCT, 157 participants, RR 0.5, 95% CI 0.3 to 0.95).

CONCLUSIONS

Probiotics reduce the risk of AAD in children. For every 7 patients that would develop diarrhea while being treated with antibiotics, one fewer will develop AAD if also receiving probiotics.

Probiotics for pediatric antibiotic-associated diarrhea: a meta-analysis of randomized placebo-controlled trials

BACKGROUND

Antibiotic treatment is known to disturb gastrointestinal microflora, which results in a range of clinical symptoms--most notably, diarrhea. This is especially important in children, for whom antibiotics are prescribed frequently. Although meta-analyses have been conducted to evaluate the ability of probiotics to prevent antibiotic-induced diarrhea in the general population, little is known about which probiotic strains and doses might be of most benefit to children. Our objective in this study was to assess the efficacy of probiotics (of any specified strain or dose) for the prevention of antibiotic-associated diarrhea in children and to assess adverse events associated with the use of probiotics when coadministered with antibiotics to children.

METHODS

A comprehensive search was performed of the major electronic databases (e.g., CENTRAL, MEDLINE, EMBASE, CINAHL, AMED) from their inception to January 2005. We also contacted experts and searched registries and meeting abstracts for additional relevant articles. Randomized controlled trials that compared probiotic treatment with placebo or no treatment, involving pediatric subjects less than 19 years of age were included. Two reviewers independently applied eligibility criteria and assessed the studies for methodological quality. Data were independently extracted by 2 reviewers and analyzed via the standard Cochrane methodology.

RESULTS

Six studies were included (total n = 707 patients). The combined results, analyzed with a per-protocol method that reported on the incidence of diarrhea during antibiotic treatment, showed significant benefit for the use of probiotics over placebo (relative risk [RR] 0.43, 95% confidence interval [CI] 0.25-0.75, Iota2 = 70.1%). In contrast, results from intention-to-treat analysis were nonsignificant overall (RR 1.01, 95% CI 0.64-1.61). Subgroup analysis on 4 studies that provided at least 5 billion single-strain colony-forming units (CFUs) daily (range 5.5-40 x 10(9) Lactobacillus GG, L. sporogens or Saccharomyces boulardii) showed strong evidence with narrow CIs for the preventative effects of probiotics for antibiotic-associated diarrhea (RR 0.36, 95% CI 0.25-0.53, Iota2 = 3.5%). No serious adverse events were reported.

INTERPRETATION

The potential protective effects of probiotics to prevent antibiotic-associated diarrhea in children do not withstand intention-to-treat analysis. Before routine use is recommended, further studies (with limited losses of subjects to follow-up) are merited. Trials should involve those probiotic strains and doses with the most promising evidence (i.e., Lactobacillus GG, L. sporogens or S. boulardii at 5-40 x 10(9) CFUs daily).

Selecting, testing and understanding probiotic microorganisms

The interest in probiotics and the modulation of microbiota for restoring and maintaining health continues to gain momentum. Research is fueled by a need to develop alternatives to antibiotics and drugs that have severe side effects. It is recognised that bacteria play a major role in human and animal health, and how scientific advances help to explain how and when probiotics work. This minireview provides an update on critical studies, particularly since 2002, that are helping to explain the mechanisms of action of probiotic organisms.

Probiotics in gastrointestinal diseases in children: hard and not-so-hard evidence of efficacy

The use of probiotics, once discussed primarily in the context of alternative medicine, is now entering mainstream medicine. However, only a few of the potential health benefits attributed to probiotics have been confirmed in well-designed, well-conducted, randomized, controlled trials. This is especially true in the pediatric population. We review here the available evidence on efficacy of probiotics in children in the prevention and treatment of gastrointestinal diseases. Although we restrict our analysis to the pediatric age, whenever potentially relevant information is available only from adult studies, they are examined as well. Probiotics have been most extensively studied in the treatment of diarrheal diseases, where their efficacy can be considered well established. Studies documenting effects in other childhood gastrointestinal illnesses are few, although some preliminary results are promising. Furthermore, only a limited number of probiotic strains have been tested, and, as the effects of different probiotic microorganisms are not equivalent, results cannot be generalized. Thus, at present, we have some positive certainties, lots of exciting promises and many unanswered questions.

Probiotics and prebiotics for gastrointestinal infections

There is growing interest in and knowledge about the potential health-promoting benefits of both probiotics and prebiotics. Multiple mechanisms of action for the beneficial effect of probiotics and prebiotics have been postulated, including prevention of pathogenic bacteria growth, production of antimicrobial agents, stimulation of mucosal barrier function, and altering immunoregulation. Clinical trials support the efficacy of probiotics in the treatment of acute infectious diarrhea, the prevention of antibiotic associated diarrhea, and the prevention of recurrent Clostridium difficile infection. Although some data support the potential benefit of probiotic therapy in traveler's diarrhea, diverticular disease, and Helicobacter pylori, the strength of this evidence is limited. This paper will review the recent literature relevant to the mechanism of action and utility of probiotics and prebiotics in the treatment of gastrointestinal infections.

Clostridium difficile–Associated Disease: An Emerging Threat to Patient Safety: Insights from the Society of Infectious Diseases Pharmacists

A formerly infrequently isolated strain of Clostridium difficile known as BI/NAP1 has resulted in geographically diverse outbreaks of C. difficile-associated disease. Such rapid dissemination and distribution of an outbreak strain of C. difficile are unprecedented, with many regions across North America, as well as several countries in Europe, being affected, all in such a short period of time. Also of note is that nontraditional hosts (e.g., otherwise healthy, noninstitutionalized persons residing in the community, some without antimicrobial exposure) have been reported to have severe disease. Data suggest that certain virulence characteristics may be responsible for more severe clinical presentations and poor outcomes. These factors (e.g., hypertoxin production, hypersporulation, antimicrobial resistance) possessed by a previously uncommon strain of C. difficile, in conjunction with particular host and environmental factors, may have precipitated the now widespread establishment of this pathogen. Antimicrobial intervention has traditionally been a mainstay of combating C. difficile-associated disease. Efforts to combat BI/NAP1 should include good antimicrobial stewardship in addition to effective infection control and environmental intervention.

Probiotics for the prevention of antibiotic-associated diarrhea and Clostridium difficile diarrhea

Antibiotic-associated diarrhea is a common clinical problem occurring in up to 25% of patients, with diarrhea owing to Clostridium difficile accounting for up to a quarter of cases. The clinical and economic costs of antibiotic-associated diarrhea are significant and better treatments are needed. Probiotics may offer potential effective therapy for antibiotic-associated diarrhea by restoring intestinal microbial balance. A number of different probiotics have been evaluated in the prevention and treatment of antibiotic-associated diarrhea in adults and children, including the nonpathogenic yeast Saccharomyces boulardii and multiple lactic-acid fermenting bacteria such as Lactobacillus rhamnosus GG (LGG). A careful review of the literature supports the efficacy of S. boulardii in the prevention of antibiotic-associated diarrhea recurrent C. difficile infection in adults, whereas LGG is useful in the treatment of antibiotic-associated diarrhea in children. Not enough data exist to currently support the use of other probiotic preparations in these conditions. Although generally safe and well tolerated, both S. boulardii and LGG should be used cautiously in immunocompromised patients. Further study of probiotics, including large, well-designed, randomized controlled dose-ranging trials, comparative trials, and cost-benefit analyses are necessary.