The vexed relationship between Clostridium difficile and inflammatory bowel disease: an assessment of carriage in an outpatient setting among patients in remission

Polymerase chain reaction test for Clostridium difficile toxin B gene reveals similar prevalence rates in children with and without inflammatory bowel disease

OBJECTIVE

Clinicians often evaluate for Clostridium difficile infection (CDI) in patients with inflammatory bowel disease (IBD) presenting with exacerbations. A highly sensitive polymerase chain reaction (PCR) test for the toxin B gene of C difficile is increasingly used to diagnose CDI. The aim of this study was to determine the prevalence of positive C difficile PCR results in children and young adults with and without active IBD compared with patients with non-IBD gastrointestinal disease.

METHODS

Fecal samples were obtained from patients with ulcerative colitis (UC, n = 76) or Crohn disease (CD, n = 69) and 51 controls followed in our gastroenterology program. Samples were analyzed for C difficile using a PCR test for the C difficile toxin B gene (BD GeneOhm Cdiff assay). Proportions of positive tests in each group were compared using the Pearson χ2 test.

RESULTS

The prevalence of positive PCR results was 11.6% in patients with CD, 18.4% in patients with UC, and 11.8% in controls (P = 0.25). There were no significant differences in the prevalence of positive C difficile results among patients with IBD with and without active disease or among patients with and without diarrhea.

CONCLUSIONS

Positive C difficile PCR results occur with similar frequency in patients with IBD with and without active disease and in patients with other gastrointestinal diseases. A positive result in a highly sensitive PCR assay that detects low copy numbers of a toxin gene in C difficile may reflect colonization in a subset of patients with IBD, confounding clinical decision making in managing disease exacerbations.

Clostridium difficile infection and inflammatory bowel disease

The prevalence of Clostridium difficile infection (CDI) in inflammatory bowel disease (IBD) has become a focus of increased attention, as the C. difficile epidemic continues to grow. Although first documented more than 20 years ago, only in recent years has the relationship between these 2 entities been better clarified, and recent epidemiologic studies have shown that IBD patients are at increased susceptibility for CDI compared with the general population. Despite this increased attention, much still remains unknown, and the overlapping clinical presentations of CDI and IBD pose barriers to diagnosis and standardized treatment. Moreover, given the relationship between mortality and severity of CDI in IBD patients, early recognition of those who are at increased risk for infection is of paramount importance to improve patient outcome.

Is clostridium difficile associated with relapse of inflammatory bowel disease? results from a retrospective and prospective cohort study in the Netherlands

BACKGROUND

Although Clostridium difficile may be associated with exacerbations in inflammatory bowel diseases (IBD), prospective studies identifying the role of C. difficile in disease activity are currently lacking. We examined the prevalence of C. difficile in feces of (1) symptomatic IBD patients retrospectively and (2) consecutive outpatients in relation to disease activity prospectively.

METHODS

From adult IBD patients with increase of symptoms, fecal samples collected between November 2010 and 2011 were tested for C. difficile, Salmonella, Shigella, Yersinia, and Campylobacter spp. Within a prospective IBD cohort, fecal samples, clinical data, and disease activity scores were collected every 3 months and during relapses. Baseline samples from all subjects (170 Crohn's disease, 116 ulcerative colitis) and additional samples from patients with changing disease activity during follow-up (57 Crohn's disease, 31 ulcerative colitis) were tested for C. difficile and when positive for toxin A and B genes by quantitative polymerase chain reaction.

RESULTS

From 104 symptomatic patients, 139 fecal samples were analyzed. Toxinogenic C. difficile and Campylobacter jejuni were detected in 3.6% and 1.8%. In the prospective cohort, C. difficile prevalence at baseline was significantly different neither between ulcerative colitis (3.4%) and Crohn's disease patients (5.9%) nor between active (8.2%) and quiescent (3.3%) disease. In multivariable analysis, C. difficile was not associated with disease activity, disease subtype, gender, antibiotic, and immunosuppressive therapy. Clostridium difficile was also not associated with disease activity within patients with changing disease activity over time (P = 0.45).

CONCLUSIONS

We found a low prevalence of C. difficile, and our findings indicate that C. difficile is not a common trigger for exacerbations of IBD in clinical practice in the Netherlands.

Clostridium difficile infection in patients with inflammatory bowel disease: An update

Inflammatory bowel disease (IBD) has many etiological factors, among which microbial factors have attracted more and more attention recently. Studies have demonstrated that the incidence of Clostridium difficile infection (CDI) in both adult and children IBD patients has been rising in recent years. Many drugs such as antibiotics, immunosuppressive agents, and acid-suppressing agents may increase the incidence of CDI. Identifying CDI and selecting effective antibiotics are keys to successful treatment, and immunological and ecological treatments are also useful choices. In this article, we will review the progress in research of CDI in IBD patients.

Similar outcomes of IBD inpatients with Clostridium difficile infection detected by ELISA or PCR assay

BACKGROUND

Clostridium difficile infection (CDI) is known as a risk factor for exacerbation of inflammatory bowel disease (IBD). CDI has been most commonly tested with enzyme-linked immunosorbent assay for toxins, but with a suboptimal sensitivity. Compared with conventional ELISA, the polymerase chain reaction-based assay (PCR) is a highly sensitive detection technique for C. difficile. However, its pure detection of only the DNA of toxin B may lead to over-treatment.

AIMS

The purpose of this study was to compare the frequency and clinical outcomes of IBD inpatients with CDI between the PCR and ELISA assays and to assess the factors associated with CDI.

METHODS

The retrospective study was performed with the IBD inpatients at Cleveland Clinic from 2009 to 2011, who were tested by either ELISA or PCR or both. Outcomes under comparison included intensive care unit transfer, length of hospital stay, requirement for gastrointestinal surgeries and all cause re-hospitalization. Multivariable analysis was performed to assess the associated factors for the combined cohorts.

RESULTS

A total of 255 patients were included, among them 222 had ELISA test, and 103 had PCR test. Thirteen (5.9 %) patients were ELISA positive, versus 14 (13.5 %) patients who were PCR positive (P = 0.02). With comparable demographic and clinical background, clinical outcomes of the ELISA and PCR positive groups showed no significant difference. Instead, the overall percentage of C. difficile positive patients had a much higher rehospitalization rate than C. difficile negative patients (P < 0.01). Multivariable analysis identified comorbidities (P = 0.03), extra-intestinal manifestations (P = 0.03) and PPI use (P < 0.01) as the associated factors for CDI.

CONCLUSION

There was a greater percentage of patients tested positive by PCR compared to ELISA. The outcomes of CDI diagnosed by PCR or ELISA, however, appeared comparable. The presence of comorbidities, extra-intestinal manifestations, and the use of PPI were found to be associated with CDI.

Phylogenetic analysis of dysbiosis in ulcerative colitis during remission

BACKGROUND

Presence of intestinal microbes is a prerequisite for the development of ulcerative colitis (UC), although deviation of the normal intestinal microbiota composition, dysbiosis, is presumably implicated in the etiology of UC.

METHODS

The fecal microbiota of 30 UC samples obtained from 15 patients who were sampled twice and from 15 healthy control subjects originating from 2 geographic locations was analyzed using highly reproducible phylogenetic microarray that has the capacity for detection and quantification of more than 1000 intestinal bacteria in a wide dynamic range.

RESULTS

The fecal microbiota composition is not significantly influenced by geographic location, age, or gender, but it differs significantly between the patients with UC and the control subjects (P = 0.0004). UC-associated microbiota is stable during remission and similar among all patients with UC. Significant reduction of bacterial diversity of members of the Clostridium cluster IV and significant reduction in the abundance of bacteria involved in butyrate and propionate metabolism, including Ruminococcus bromii et rel. Eubacterium rectale et rel., Roseburia sp., and Akkermansia sp. are markers of dysbiosis in UC. Increased abundance of (opportunistic) pathogens including Fusobacterium sp., Peptostreptococcus sp., Helicobacter sp., and Campylobacter sp. as well as Clostridium difficile were found to be associated with UC.

CONCLUSIONS

Dysbiosis in UC is stable in time and shared between patients from different geographic locations. The microbial alterations offer a mechanistic insight into the pathogenesis of the disease.

The colonic microbiota and colonic disease

The colonic ecosystem differs from that in the proximal gut in several important respects. The colonic microbiota represents the largest population of microbes colonizing humans from birth. Constraints on bacterial numbers, composition, and interaction with the host involve not only the innate and acquired immune system, but also the colonic mucin structure. While the microbiota provides beneficial protective, trophic, nutritional, and metabolic signals for the host, it may become a risk factor for disease depending on context and host susceptibility. Technological advances including DNA-based high-throughput compositional analysis have linked changes in the indigenous microbiota with several human diseases. In some instances, these findings have the potential to serve as new biomarkers of risk of disease. In this overview, recent advances are focused upon in relation to irritable bowel syndrome, inflammatory bowel disease, and colon cancer. The possibility that the therapeutic solution to some of these disorders may reside within the microbiota will also be addressed.

Risk factors and outcome of PCR-detected Clostridium difficile infection in ileal pouch patients

BACKGROUND

The clinical implication of Clostridium difficile infection (CDI) in patients with ileal pouch-anal anastomosis (IPAA) for underlying inflammatory bowel disease (IBD) has not been well studied. This study was designed to investigate the cumulative incidence, risk factors, and outcome of CDI in patients with ileal pouches.

METHODS

Consecutive IPAA patients (n = 196) from the subspecialty Pouchitis Clinic with an increase of at least three stools per day more from the postoperative baseline for more than 4 weeks were enrolled from October 2010 to December 2011. CDI was diagnosed based on the presence of symptoms and positive polymerase chain reaction (PCR)-based stool test for C. difficile toxin B. Risk factors for CDI were assessed with univariate and multivariate analyses. All patients with CDI (n = 21) were treated with oral vancomycin (500 - 1000 mg/day) for 2-4 weeks. The treatment outcome of these patients was documented.

RESULTS

Twenty-one patients (10.7%) were diagnosed with CDI. On univariate analysis, patients with CDI had more stool frequency (P = 0.014) and significant current weight loss (P = 0.003) than patients with no CDI. In logistic regression analysis, there was a trend that recent hospitalization (odds ratio [OR] = 4.00, 95% confidence interval [CI], 0.95-16.84) might be associated with CDI. Of the 14 CDI patients with follow-up data, eight (57.1%) had either recurrent (n = 5) or refractory (n = 3) CDI after oral vancomycin therapy.

CONCLUSIONS

A high index of suspicion for CDI in pouch patients should be given to those with recent hospitalization or constitutional symptoms, such as weight loss. Recurrent or refractory CDI is common, even with standard oral vancomycin therapy.

Intestinal microbiota: a source of novel biomarkers in inflammatory bowel diseases?

The human intestine harbours a complex microbial ecosystem that performs manifold functions important to the nutrition and health of its host. Extensive study has revealed that the composition of the intestinal microbiota is altered in individuals with inflammatory bowel disease (IBD). The IBD associated intestinal microbiota generally has reduced species richness and diversity, lower temporal stability, and disruption of the secreted mucus layer structure. Multiple studies have identified certain bacterial taxa that are enriched or depleted in IBD including Enterobacteriaceae, Ruminococcus gnavus, and Desulfovibrio (enriched) and Faecalibacterium prausnitzii, Lachnospiraceae, and Akkermansia (depleted). Additionally, the relative abundance of some taxa appears to correlate with established markers of disease activity such as Enterobacteriaceae (enriched) and Lachnospiraceae (depleted). Signature shifts in fecal microbial community composition may therefore prove to be valuable as diagnostic biomarkers, particularly for longitudinal monitoring of disease activity and response to treatments.

Clostridium difficile infection in the inflammatory bowel disease patient

Clostridium difficile infection (CDI) has been increasing in frequency and severity in patients with inflammatory bowel disease (IBD). Population based and single center studies have shown worse clinical outcomes in concomitant CDI and IBD, with several reporting longer length of hospital stay, higher colectomy rates and increased mortality. Clinically, CDI may be difficult to distinguish from an IBD flare and may range from an asymptomatic carrier state to severe life threatening colitis. The traditional risk factors for CDI have included hospitalization, antibiotic use, older age and severe co-morbid disease but IBD patients have several distinct characteristics including younger age, community acquisition, lack of antibiotic exposure, colonic IBD and steroid use. CDI can occur in the small bowel and specifically in ulcerative colitis patients who have had a colectomy and an ileal pouch anal anastomosis. PCR based assays and combination Elisa algorithms have improved the sensitivity and specificity of testing, though in IBD patients have raised clinical questions about how to best manage diarrhea in the setting of possible C. difficile colonization. Treatment modalities for CDI have not been examined in randomized clinical trials in the IBD population. Newer antibiotics, immunotherapy and fecal microbiota transplantation may alter current treatment strategies. This review will focus on the unique epidemiology of CDI in IBD patients, detail clinical disease states, and provide updated diagnostic strategies, prevention and treatment options.

Impact of Clostridium difficile colitis on 5-year health outcomes in patients with ulcerative colitis

BACKGROUND

Clostridium difficile colitis (CDC) is associated with an increased short-term mortality risk in hospitalised ulcerative colitis (UC) patients. We sought to determine whether CDC also impacts long-term risks of adverse health events in this population.

AIM

To determine whether CDC also impacts long-term risks of adverse health events in this population.

METHODS

A population-based retrospective cohort study was conducted of UC patients hospitalised in Ontario, Canada between 2002 and 2008. Patients with and without CDC were compared on the rates of adverse health events. The primary outcomes were the 5-year adjusted risks of colectomy and death.

RESULTS

Among 181 patients with CDC and 1835 patients without CDC, the 5-year cumulative colectomy rates were 44% and 33% (P = 0.0052) and the 5-year cumulative mortality rates were 27% and 14% (P < 0.0001) respectively. CDC was associated with a higher adjusted 5-year risk of mortality [adjusted hazard ratio (aHR) 2.40, 95% CI 1.37-4.20], but not of colectomy (aHR 1.18, 95% CI 0.90-1.54). CDC impacted mortality risk both during index hospitalisation (adjusted odds ratio 8.90, 95% CI 2.80-28.3) as well as over 5 years following hospital discharge among patients who recovered from their acute illness (aHR 2.41, 95% CI 1.37-4.22). Colectomy risk was not influenced by CDC in this cohort.

CONCLUSION

Clostridium difficile colitis is associated with increased short-term and long-term mortality risks among hospitalised ulcerative colitis patients. As colectomy risk is not similarly impacted by Clostridium difficile colitis, factors predictive of death among C. difficile-infected ulcerative colitis patients require elucidation.

The microbiota in inflammatory bowel disease: friend, bystander, and sometime-villain

Ulcerative colitis and Crohn's disease, collectively known as inflammatory bowel disease, represent the heterogeneous outcome of three colliding influences: genetic risk factors, environmental modifiers, and immune effector mechanisms of tissue injury. The nature of these inputs is complex, with each having distinct and overlapping contributions to ulcerative colitis and Crohn's disease. Identification of specific genetic risk factors has improved the understanding of specific pathways to disease, but the primacy of environmental or lifestyle factors linked to changes in the gut microbiota, particularly in early life, is increasingly evident. Clarification of the molecular basis of host-microbe interactions in health and in susceptible individuals promises novel therapeutic strategies.

Inflammatory bowel disease: role of diet, microbiota, life style

Inflammatory bowel disease (IBD) encompassed several chronic inflammatory disorders leading to damage of the gastrointestinal tract (GI). The 2 principal forms of these disorders are ulcerative colitis (UC) and Crohn disease (CD). Bacteria are involved in the etiology of IBD, and the genetic susceptibility, environmental factors, and lifestyle factors can affect the individual's predisposition to IBD. The review discusses the potential role of environmental factors such as diet and microbiota as well as genetics in the etiology of IBD. It is suggested that microbial ecosystem in the human bowel colonizing the gut in many different microhabitats can be influence by diet, leading to formation of metabolic processes that are essential form the bowel metabolism.

Detecting and treating Clostridium difficile infections in patients with inflammatory bowel disease

The prevalence of CDI in patients with IBD has increased over the last decade. The excess morbidity and mortality associated with CDI appears to be greater in patients with IBD than in those without preexisting bowel disease. The risk factors for CDI in IBD and non-IBD populations appear similar; unique IBD-related risk factors are use of maintenance immunosuppression and extent and severity of prior colitis. Nevertheless, a significant proportion of CDI-IBD patients may have the disease without traditional risk factors (ie, antibiotic use, recent hospitalization). The absence of such risk factors must not preclude considering CDI in the differential diagnosis of IBD patients presenting with a disease flare. Vancomycin and metronidazole appear to have similar efficacy with vancomycin being the preferred agent for severe disease. Early surgical consultation is key for improving outcomes of patients with severe disease. Several gaps in research exist; prospective multicenter cohorts of CDI-IBD are essential to improve our understanding of the impact of CDI on IBD patients and define appropriate therapeutic regimens to improve patient outcomes.

Prospective observational study on antibiotic-associated bloody diarrhea: report of 21 cases with a long-term follow-up from Turkey

OBJECTIVE

Antibiotic-associated hemorrhagic colitis is a distinct form of antibiotic-associated bloody diarrhea (AABD) in which Clostridium difficile is absent. Although the cause is not exactly known, reports have suggested the role of Klebsiella oxytoca and/or C. difficile.

MATERIALS AND METHODS

Between 2001 and 2006, stool samples of 21 consecutive patients with AABD were cultured for common enteric pathogens and K. oxytoca, and were tested for the presence of parasites and C. difficile toxin A+B within the first 24 h of their initial admission and a colonoscopy was performed when available. The patients were followed up prospectively by telephone interviews.

RESULTS

The occurrence of symptoms ranged between 6 h and 14 days following the first dose of the antibiotic responsible and the duration of the AABD ranged between 6 h and 21 days. The antibiotic responsible was oral ampicillin/sulbactam in 18 (85%) cases. C. difficile toxin A+B production by enzyme-linked immunosorbent assay and K. oxytoca growth in stool cultures were detected in six (29%) and 11 (51%) of 21 patients, respectively. Endoscopic morphology and histology in a limited number of patients revealed no more than a nonspecific inflammation and acute colitis, respectively.

CONCLUSION

This study confirms that antibiotic-associated hemorrhagic colitis, as a distinct entity in relation to K. oxytoca, is seen in half of the patients with AABD. Most of the cases are seen within a week following the antibiotic use. Almost all of the patients did not develop any flares during the long-term antibiotic-free follow-up. In some of the patients with AABD, there was coexistence of K. oxytoca with C. difficile toxin A+B.

Carriage of Clostridium difficile in outpatients with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common, typically chronic and sometimes disabling gastrointestinal condition of uncertain aetiology. Recently, a variety of links to gastrointestinal infections have been described including the onset of IBS following exposure to enteric pathogens and an apparent predisposition to gastrointestinal infection. The prevalence of Clostridium difficile in a population of IBS outpatients (n = 87) in the absence of established risk factors for the acquisition of C. difficile infection was examined. Overall, 5.7 % of patients (n = 5) carried culturable C. difficile and 4.6 % (n = 4) of isolates were toxigenic, belonging to toxinotype group 0, compared with 1.1 % (n = 1) for the healthy control group (n = 88). These isolates were members of toxigenic PCR ribotype groups 005 and 050 (IBS group) and 062 (control group) and were identified further as three individual strains by PFGE. Although no significant difference was observed between IBS patients and healthy volunteers, these findings support the concept that a subpopulation of IBS patients may be susceptible to gastrointestinal infection.

Clostridium difficile: epidemiology, pathogenesis, management, and prevention of a recalcitrant healthcare-associated pathogen

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.

Prevalence of Clostridium Difficile in Excluded Colons

Clostridium difficile infection is associated with substantial morbidity and mortality, increased duration of hospitalization, and a marked economic impact. Several case reports and case series have described C. difficile infection in excluded bowels or immediately after reversal of defunctioning ileostomy. The aim of this prospective study is to detect whether the excluded colon is associated with a higher rate of C. difficile colonization than the normal population, which may increase the risk of C. difficile infection. Patients with defunctioning loop ileostomy, undergoing closure of ileostomy to restore bowel continuity, were prospectively recruited. Two stool samples were collected from the ileostomy effluent before closure of ileostomy and two after the procedure including the first bowel movement. All samples were cultured for C. difficile and analyzed for toxins A and B by a Premier EIA test. Demographic data and possible confounding factors were observed and recorded. Twenty-fine adult patients were recruited to this study; five patients were subsequently excluded. Two patients had positive stool cultures for C. difficile in the postoperative samples and another patient developed clinical pseudomembranous colitis with positive toxin. This indicates a possible colonization rate of 3 to 38 per cent (95% confidence interval). Four observed cases out of the 20 subjects taking part in this study would confidently conclude that C. difficile colonization in the excluded colon is 6 to 44 per cent, i.e., higher than the incidence in the healthy adult population, which is 3 per cent. However, the findings of this study prompt larger and well-powered studies to confirm these findings.

Gastrointestinal infection as a trigger for inflammatory bowel disease

PURPOSE OF REVIEW

There is accumulating evidence on the importance of microbes in the development and maintenance of both the intestinal and immune systems. This review focuses on the current findings on the role of gastrointestinal pathogens in the cause of chronic inflammatory bowel disease.

RECENT FINDINGS

A number of intestinal pathogens including Mycobacterium avium subspecies paratuberculosis, adherent-invasive Escherichia coli, and Campylobacter species are associated at fairly high prevalence with Crohn's disease, while two recent studies found a low prevalence for cytomegalovirus. In a prospective study, M. avium subspecies paratuberculosis detection in early Crohn's disease was low and comparable to controls, while much higher in an established inflammatory bowel disease cohort. In the pediatric setting, a high prevalence of Clostridium difficile was seen in both active and inactive Crohn's disease and ulcerative colitis patients. Some studies have speculated that Salmonella or Campylobacter infection may increase the risk of inflammatory bowel disease on long-term follow-up, but detection bias was found to obscure the risk. Recent studies in mouse models have demonstrated that a combination of factors, including viral pathogens, genetic susceptibility, and commensal microflora, can lead to intestinal pathology.

SUMMARY

No evidence for causation of inflammatory bowel disease by a single agent has been found, whereas a number of microbes have been strongly associated with the presence of disease. The majority of recent studies support a role for the ability of intestinal pathogens to promote chronic inflammation in individuals with genetic susceptibility and/or other environmental factors which remain to be identified. These factors may include subsets of commensal microflora.

Clostridium difficile prevalence rates in a large healthcare system stratified according to patient population, age, gender, and specimen consistency

We evaluated Clostridium difficile prevalence rates in 2,807 clinically indicated stool specimens stratified by inpatient (IP), nursing home patient (NH), outpatient (OP), age, gender, and specimen consistency using bacterial culture, toxin detection, and polymerase chain reaction (PCR) ribotyping. Rates were determined based on the detection of toxigenic C. difficile isolates. We identified significant differences in the rates between patient populations and with age. Specimens from NH had a higher rate (46%) for toxigenic C. difficile than specimens from IP (18%) and OP (17%). There were no gender-related differences in the rates. Liquid specimens had a lower rate (15%) than partially formed and soft specimens (25%) and formed specimens (18%) for the isolation of toxigenic C. difficile. The nontoxigenic rate was lowest for NH (4%) and highest for patients<20 years of age (23%). We identified 31 different toxigenic ribotypes from a sampling of 190 isolates that showed the lowest diversity in NH. Fluoroquinolone resistance was observed in 93% of the 027 isolates, all of the 053 isolates, and in four other ribotypes. We observed different rates for toxigenic C. difficile in stratified patient populations, with the highest rate for NH, a low overall nontoxigenic rate, and fluoroquinolone resistance.

Brain-gut-microbe communication in health and disease

Bidirectional signalling between the gastrointestinal tract and the brain is regulated at neural, hormonal, and immunological levels. This construct is known as the brain–gut axis and is vital for maintaining homeostasis. Bacterial colonization of the intestine plays a major role in the post-natal development and maturation of the immune and endocrine systems. These processes are key factors underpinning central nervous system (CNS) signaling. Recent research advances have seen a tremendous improvement in our understanding of the scale, diversity, and importance of the gut microbiome. This has been reflected in the form of a revised nomenclature to the more inclusive brain–gut–enteric microbiota axis and a sustained research effort to establish how communication along this axis contributes to both normal and pathological conditions. In this review, we will briefly discuss the critical components of this axis and the methodological challenges that have been presented in attempts to define what constitutes a normal microbiota and chart its temporal development. Emphasis is placed on the new research narrative that confirms the critical influence of the microbiota on mood and behavior. Mechanistic insights are provided with examples of both neural and humoral routes through which these effects can be mediated. The evidence supporting a role for the enteric flora in brain–gut axis disorders is explored with the spotlight on the clinical relevance for irritable bowel syndrome, a stress-related functional gastrointestinal disorder. We also critically evaluate the therapeutic opportunities arising from this research and consider in particular whether targeting the microbiome might represent a valid strategy for the management of CNS disorders and ponder the pitfalls inherent in such an approach. Despite the considerable challenges that lie ahead, this is an exciting area of research and one that is destined to remain the center of focus for some time to come.

Clostridium difficile carriage in elderly subjects and associated changes in the intestinal microbiota

Clostridium difficile is an important nosocomial pathogen associated particularly with diarrheal disease in elderly individuals in hospitals and long-term care facilities. We examined the carriage rate of Clostridium difficile by culture as a function of fecal microbiota composition in elderly subjects recruited from the community, including outpatient, short-term respite, and long-term hospital stay subjects. The carriage rate ranged from 1.6% (n = 123) for subjects in the community, to 9.5% (n = 43) in outpatient settings, and increasing to 21% (n = 151) for patients in short- or long-term care in hospital. The dominant 072 ribotype was carried by 43% (12/28) of subjects, while the hypervirulent strain R027 (B1/NAP1/027) was isolated from 3 subjects (11%), 2 of whom displayed C. difficile associated diarrhea (CDAD) symptoms at the time of sampling. Emerging ribotypes with enhanced virulence (078 and 018) were also isolated from two asymptomatic subjects. Pyrosequencing of rRNA gene amplicons was used to determine the composition of the fecal microbiota as a surrogate for the microbial population structure of the distal intestine. Asymptomatic subjects (n = 20) from whom C. difficile was isolated showed no dramatic difference at the phylum or family taxonomic level compared to those that were culture negative (n = 252). However, in contrast, a marked reduction in microbial diversity at genus level was observed in patients who had been diagnosed with CDAD at the time of sampling and from whom C. difficile R027 was isolated.

Commensal bacteria: the link between IBS and IBD?

PURPOSE OF REVIEW

To review interactions between the microbiota and the host in irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), emphasizing areas of commonality and divergence.

RECENT FINDINGS

Several lines of evidence support a role for the microbiota in the pathogenesis of IBS and IBD. Some implicate the microbiota in a general sense and relate to variations in the composition of the microbiota between IBS, IBD and controls; others relate to the ability of events and interventions that disrupt/modify the microbiota to predispose to the development of IBS and IBD and, others still refer to reports of the ability of antibiotics, prebiotics or probiotics, in selected circumstances, to beneficially alter their clinical course. Enthusiasm for a role for a specific organism in precipitating disease has been largely (and contentiously) linked to IBD. Many issues remain unresolved and must wait for the application of modern microbiological techniques to well characterized populations and well matched controls.

SUMMARY

It makes sense, given the size and complexity of the microbiota and its role in homeostasis, that the microbiota and its interactions with the host would play a role in the pathogenesis of IBS and IBD; sorting out the details has proven challenging but does offer new therapeutic avenues for both disorders.

Practice of gastroenterologists in treating flaring inflammatory bowel disease patients with clostridium difficile: antibiotics alone or combined antibiotics/immunomodulators?

BACKGROUND

The optimal management of Clostridium difficile infection (CDI) in flaring inflammatory bowel disease (IBD) patients has not been defined. Limited data suggest that coadministration of immunomodulators (IM) with antibiotics (AB) results in a worse outcome. We investigated the prevalent practice among North American gastroenterologists in this scenario.

METHODS

A structured questionnaire presented the clinical cases of two hospitalized patients with ulcerative colitis and concomitant CDI, either with or without prior IM treatment. The questionnaire was distributed to a sample of gastroenterologists at medical centers across North America. Respondents were requested to denote their therapeutic choices for these patients.

RESULTS

The survey included 169 gastroenterologists, 122 from the US and 47 from Canada, with an average of 12 ± 10 years of experience in gastroenterology. Forty-two (25%) of the respondents were IBD experts. Seventy-seven (46%) respondents elected to add an IM in combination with AB, whereas 82/169 (54%) treated the flare with AB alone (P = NS). The rate of administering combined AB+IM was similar for the IBD experts and the non-IBD experts. Only 11% of respondents withdrew maintenance azathioprine upon the diagnosis of CDI. More IBD experts stopped azathioprine treatment compared to the non-IBD experts (12/42 versus 6/127, P < 0.001). Overall, 65% of surveyed gastroenterologists stated they believe these patients are afflicted by two simultaneous but separate disease processes.

CONCLUSIONS

There is significant disagreement among gastroenterologists on whether combination AB+IM or AB alone should be given to IBD patients with CDI-associated flares. Controlled trials are needed to investigate the optimal management approach to this clinical dilemma.

Increased health burden associated with Clostridium difficile diarrhoea in patients with inflammatory bowel disease

BACKGROUND

Clostridium difficile (C. difficile) infection in hospitals in developed countries continues to be a major public health hazard despite increased control measures including review of antibiotic policies and hygiene measures. Patients with colitis are thought to be particularly vulnerable to C. difficile associated diarrhoea (CDAD). Identifying the clinical burden among hospitalised patients admitted with inflammatory bowel disease is an essential first step towards identifying and treating severe C. difficile infection in such individuals.

AIM

To determine excess morbidity and in-hospital mortality associated with hospital acquired CDAD in patients with inflammatory bowel disease (IBD-CDAD-HAI) admitted to NHS hospitals in England compared with those admitted for inflammatory bowel disease alone.

METHODS

Time trends study of all admissions to NHS hospitals between 2002/03 and 2007/08. We developed case definitions for IBD-CDAD-HAI patients. The primary outcomes were in-hospital mortality and length of stay. The secondary outcome was gastrointestinal surgery.

RESULTS

Patients in the IBD-CDAD-HAI group were more likely to die in hospital (adjusted OR 6.32), had 27.9 days longer in-patient stays and higher gastrointestinal surgery rates (adjusted OR 1.87) than patients admitted for inflammatory bowel disease alone.

CONCLUSION

Patients with inflammatory bowel disease admitted to NHS hospitals in England with co-existent C. difficile infection are at risk of greater in-hospital mortality and morbidity than patients admitted for inflammatory bowel disease alone.

Clostridium difficile infection in hospitalized children in the United States

OBJECTIVES

To evaluate the trend in Clostridium difficile infection (CDI) among hospitalized children in the United States and to evaluate the severity of and risk factors associated with these cases of CDI.

DESIGN

A retrospective cohort study using the triennial Healthcare Cost and Utilization Project Kids' Inpatient Database for the years 1997, 2000, 2003, and 2006.

SETTING

Hospitalized children in the United States.

PARTICIPANTS

A nationally weighted number of patients (10 474 454) discharged from the hospital, 21 274 of whom had CDI.

MAIN EXPOSURE

Discharge diagnosis of CDI.

MAIN OUTCOME MEASURES

Trend in cases of CDI; effect and severity were measured by length of hospital stay, hospitalization charges, colectomy rate, and death rate.

RESULTS

There was an increasing trend in cases of CDI, from 3565 cases in 1997 to 7779 cases in 2006 (P < .001). Patients with CDI had an increased risk of death (adjusted odds ratio [OR], 1.20; 95% confidence interval [95% CI], 1.01-1.43), colectomy (adjusted OR, 1.36; 95% CI, 1.04-1.79), a longer length of hospital stay (adjusted OR, 4.34; 95% CI, 3.97-4.83), and higher hospitalization charges (adjusted OR, 2.12; 95% CI, 1.98-2.26). There was no trend in death, colectomy, length of hospital stay, or hospitalization charges during the 4 time periods (ie, 1997, 2000, 2003, and 2006). The risk of comorbid diagnoses associated with CDI included inflammatory bowel disease, with an OR of 11.42 (95% CI, 10.16-12.83), and other comorbid diagnoses associated with immunosuppression or antibiotic administration.

CONCLUSIONS

There is an increasing trend in CDI among hospitalized children, and this disease is having a significant effect on these children. In contrast to adults, there is no increasing trend in the severity of CDI in children. Children with medical conditions (including inflammatory bowel disease and immunosuppression) or conditions requiring antibiotic administration are at high risk of CDI.

Clostridium difficile infection in patients with ulcerative colitis: investigations of risk factors and efficacy of antibiotics for steroid refractory patients

BACKGROUND AND OBJECTIVE

The incidence of Clostridium difficile infection (CDI) has increased throughout the world and patients with ulcerative colitis (UC) are at a high risk for CDI. Potentially, CDI can exacerbate UC. Therefore, knowledge on the prevalence of CDI should contribute to better management of UC patients.

METHODS

The presence of toxin A antigen was defined as CDI, and the outcome of the test in patients with active UC during 2006-2009 was reviewed for identifying patients with CDI. Demographic data (disease profile, clinical response to medications and the need for colectomy) in UC patients with CDI were compared with the data from CDI free UC patients.

RESULTS

Fifty-five of 137 patients (40.1%) were CDI positive. Univariate and multivariate analyses revealed that CDI was not associated with any demographic factor. Intensive antibiotic therapy spared five of 17 (29.4%) steroid refractory patients with CDI from steroids. CDI was not a predictor of colectomy although this could be an outcome of efficient eradication strategy.

CONCLUSION

CDI was not associated with any demographic factor or colectomy rate. However, CDI eradication therapy allowed some refractory patients to withdraw from steroids. Patients with active UC benefit from regular CDI test and eradication treatment for CDI.

Clostridium difficile infection and treatment in the pediatric inflammatory bowel disease population

OBJECTIVE

Recent changes in the epidemiology of Clostridium difficile infection include an increase in the incidence of C difficile-associated disease (CDAD) and the identification of patients with inflammatory bowel disease (IBD) as a group at risk. In addition, the effectiveness of antimicrobial therapies has been questioned. Our aim was to estimate the incidence of CDAD in a pediatric IBD population and review treatment efficacy.

PATIENTS AND METHODS

We identified patients ages 18 years or younger from our center's IBD database who tested positive for C difficile toxin A and/or B between August 1, 2007 and December 31, 2008. Demographic information and treatment details were recorded. Chi-square and Fisher exact tests were used to compare categorical variables and the Student t test was used for continuous variables.

RESULTS

From 372 pediatric patients with IBD, we identified 29 patients who experienced a total of 40 cases of CDAD. The annualized incidence rate of CDAD was 7.2%. Initial treatment was successful in 17 cases (43%). Eventual success was documented with metronidazole in 15 cases (41%), with vancomycin in 16 cases (43%), and with other agents or a combination of agents in 6 cases (16%). Age, sex, and IBD type were not associated with initial treatment outcome or recurrence. The choice of initial antimicrobial treatment was not associated with treatment outcome. The type of IBD therapy medication was not associated with the likelihood of CDAD recurrence, although the use of anti-inflammatory therapy was positively associated with initial antimicrobial treatment success.

CONCLUSIONS

CDAD occurred frequently in our cohort of pediatric patients with IBD. Antimicrobial treatment success was achieved equally with either metronidazole or vancomycin. Initial treatment failed more than half of the time, regardless of medication choice. Apparent lack of antimicrobial efficacy in resolving symptoms may reflect resistant C difficile infection or increased IBD severity in a subset of patients who are C difficile carriers. Awareness of the potential for a high incidence of CDAD and frequent failure rate of initial therapy is important in the management of children with IBD.

Systematic review: Clostridium difficile and inflammatory bowel disease

BACKGROUND

There is increasing concern about the apparently rising incidence and worsening outcome of Clostridium difficile infection (CDI) associated with inflammatory bowel disease (IBD). We have systematically reviewed the literature to evaluate the incidence, risk factors, endoscopic features, treatment and outcome of CDI complicating IBD.

AIM

To systematically review: clostridium difficile & inflammatory bowel disease.

METHODS

Structured searches of Pubmed up to September 2010 for original, cross-sectional, cohort and case-controlled studies were undertaken.

RESULTS

Of 407 studies, 42 met the inclusion criteria: their heterogeneity precluded formal meta-analysis. CDI is commoner in active IBD, particularly ulcerative colitis, than in controls. Certainty about a temporal trend to its increasing incidence in IBD is compromised by possible detection bias and miscoding. Risk factors include immunosuppressants and antibiotics, the latter less commonly than in controls. Endoscopy rarely shows pseudomembranes and is unhelpful for diagnosing CDI in IBD. There are no controlled therapeutic trials of CDI in IBD. In large studies, outcome of CDI in hospitalised IBD patients appears worse than in controls.

CONCLUSIONS

The complication of IBD by Clostridium difficile infection has received increasing attention in the past decade, but whether its incidence is really increasing or its outcome worsening remains unproven. Therapeutic trials of Clostridium difficile infection in IBD are lacking and are needed urgently.

Impact of Clostridium difficile infection in patients with ulcerative colitis

BACKGROUND

Clostridium difficile infection (CDI) is becoming prevalent in general population as well as in patients with inflammatory bowel disease (IBD).

AIM

The aim of the study was to identify risk factors for CDI in patients with ulcerative colitis (UC) and to assess outcome of UC in patients following CDI.

METHODS

UC inpatients or outpatients who had positive results for C. difficile toxins A and B between 2000 and 2006 were identified (N=39) and matched for age and gender to UC patients who were negative C. difficile toxins and had never been diagnosed with CDI (N=39). Records were reviewed for adverse clinical outcome, defined as colectomy within 3 months of C. difficile testing. Conditional logistic regression was used to analyze multivariable association to identify risk factors for CDI and for adverse clinical outcome.

RESULTS

A total of 78 subjects were analyzed, 60% were males. Median age was 39. Among 39 patients with CDI, 20 (47.2%) were diagnosed as outpatients, 50% failed treatment with the first antibiotic monotherapy, and 21.2% had recurrent infection. Antibiotic exposure within 30 days prior to C. difficile testing was found to be associated with an increased risk for CDI with an odds ratio of 12.0 (95% CI 1.2, 124.2) Subsequent colectomy within 3 months after CDI diagnosis, was not associated with CDI in both univariable and multivariable analyses. After adjusting for CDI, lack of 5-aminosalicylic acid (ASA) in the treatment regimen was significantly associated with colectomy with an odds ratio of 3.3 (95% CI: 1.2, 9.4). There was no UC- or CDI-associated mortality in this case series.

CONCLUSIONS

Recent antibiotic exposure was a risk factor for CDI in UC patients. Interestingly, CDI does not seem to adversely affect short-term adverse clinical outcome (colectomy).

Microbial induction of immunity, inflammation, and cancer

The human microbiota presents a highly active metabolic that influences the state of health of our gastrointestinal tracts as well as our susceptibility to disease. Although much of our initial microbiota is adopted from our mothers, its final composition and diversity is determined by environmental factors. Westernization has significantly altered our microbial function. Extensive experimental and clinical evidence indicates that the westernized diet, rich in animal products and low in complex carbohydrates, plus the overuse of antibiotics and underuse of breastfeeding, leads to a heightened inflammatory potential of the microbiota. Chronic inflammation leads to the expression of certain diseases in genetically predisposed individuals. Antibiotics and a “clean” environment, termed the “hygiene hypothesis,” has been linked to the rise in allergy and inflammatory bowel disease, due to impaired beneficial bacterial exposure and education of the gut immune system, which comprises the largest immune organ within the body. The elevated risk of colon cancer is associated with the suppression of microbial fermentation and butyrate production, as butyrate provides fuel for the mucosa and is anti-inflammatory and anti-proliferative. This article will summarize the work to date highlighting the complicated and dynamic relationship between the gut microbiota and immunity, inflammation and carcinogenesis.

Clostridium difficile infection: epidemiology, risk factors and management

The epidemiology of Clostridium difficile infection (CDI) has changed over the past decade. There has been a dramatic worldwide increase in its incidence, and new CDI populations are emerging, such as those with community-acquired infection and no previous exposure to antibiotics, children, pregnant women and patients with IBD. Diagnosis of CDI requires identification of C. difficile toxin A or B in diarrheal stool. The accuracy of current diagnostic tests remains inadequate and the optimal diagnostic testing algorithm has not been defined. The first-line agents for CDI treatment are metronidazole and vancomycin, with the latter being the preferred agent in patients with severe disease as it has significantly superior efficacy. The incidence of metronidazole treatment failures has increased, emphasizing the need to find alternative treatment options. Disease recurrence continues to occur in 20-40% of patients and its treatment remains challenging. In patients with CDI who develop fulminant colitis, early surgical consultation is essential. Intravenous immunoglobulin and tigecycline have been used in patients with severe refractory disease but delaying surgery may be associated with worse outcomes. Infection control measures are key to prevent horizontal transmission of infection. Ongoing research into effective treatment protocols and prevention is essential.

The colonic microflora and probiotic therapy in health and disease

PURPOSE OF REVIEW

Host-microbe dialogue is involved not only in maintenance of mucosal homeostasis but also in the pathogenesis of several infectious, inflammatory, and neoplastic disorders of the gut. This has led to a resurgence of interest in the colonic microbiota in health and disease. Recent landmark findings are addressed here.

RECENT FINDINGS

Reciprocal signalling between the immune system and the microbiota plays a pivotal role in linking alterations in gut microbiota with risk of metabolic disease in the host, notably insulin resistance, obesity, and chronic low-grade inflammation. Loss of ancestral indigenous organisms consequent upon a modern lifestyle may contribute to an increased frequency of various metabolic and immuno-allergic diseases. The potential to address this underpins the science of pharmabiotics.

SUMMARY

Advances in understanding host-microbe interactions within the gut can inform rational probiotic or pharmabiotic selection criteria. In addition, the gut microbiota may be a repository for drug discovery as well as a therapeutic target.

Clostridium difficile infection and inflammatory bowel disease: Understanding the evolving relationship

Clostridium difficile (C. difficile) infection (CDI) is the leading identifiable cause of antibiotic-associated diarrhea. While there is an alarming trend of increasing incidence and severity of CDI in the United States and Europe, superimposed CDI in patients with inflammatory bowel disease (IBD) has drawn considerable attention in the gastrointestinal community. The majority of IBD patients appear to contract CDI as outpatients. C. difficile affects disease course of IBD in several ways, including triggering disease flares, sustaining activity, and in some cases, acting as an “innocent” bystander. Despite its wide spectrum of presentations, CDI has been reported to be associated with a longer duration of hospitalization and a higher mortality in IBD patients. IBD patients with restorative proctocolectomy or with diverting ileostomy are not immune to CDI of the small bowel or ileal pouch. Whether immunomodulator or corticosteroid therapy for IBD should be continued in patients with superimposed CDI is controversial. It appears that more adverse outcomes was observed among patients treated by a combination of immunomodulators and antibiotics than those treated by antibiotics alone. The use of biologic agents does not appear to increase the risk of acquisition of CDI. For CDI in the setting of underlying IBD, vancomycin appears to be more efficacious than metronidazole. Randomized controlled trials are required to clearly define the appropriate management for CDI in patients with IBD.

Impact of Clostridium difficile on inflammatory bowel disease

Clostridium difficile infection (CDI) has been increasing in incidence among those with underlying inflammatory bowel disease (IBD) and is associated with substantial morbidity, the need for surgery and even mortality. The similar clinical presentation between CDI and a flare of underlying IBD makes prompt diagnosis essential to prevent deterioration which would accompany an escalation of immunosuppression in the absence of appropriate antibiotic therapy. Classical risk factors (antibiotic or healthcare exposure) or clinical findings (pseudomembranes) may not be found in many IBD patients with CDI and should not be considered essential for entertaining the diagnosis. Enzyme immunoassays detecting both toxins A and B remain the most widely used test for diagnosis and have acceptable sensitivity, but may require testing of multiple samples in select situations. Both vancomycin and metronidazole appear to be effective and treatment with oral vancomycin is preferred in those with severe disease, including those who require hospitalization. Appropriate infection control measures are essential to restrict patient-to-patient spread within healthcare environments and to prevent recurrences. Several novel therapies are currently under study, including new antibiotic agents and monoclonal antibodies targeted against the toxins. There is a need to broaden these studies to the IBD population. There is also the need to prospectively examine whether CDI has long-term disease-modifying consequences in those with underlying IBD.

The role of bacteria in the pathogenesis of inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) have features that suggest bacterial involvement, and all genetic models of inflammatory bowel disease (IBD) require the presence of commensal bacteria. CD is associated with innate immune response genes such as NOD2/CARD15 and the autophagy genes ATG16L1 and IRGM. However, IBD responds to immunosuppression, suggesting that any bacteria involved are not acting as conventional pathogens. Molecular techniques are rapidly advancing our knowledge of the gut microbiota. In CD there is reduced diversity, and notably a reduction in the probiotic Faecalibacterium prausnitzii, the presence of which in the terminal ileum is associated with a reduced risk of recurrence following surgery. There is also a consistent increase in mucosa-associated Escherichia coli with an "adherent and invasive" phenotype, which allows them to replicate inside macrophages and induce granulomas. Speculation that CD could be caused by the Mycobacterium avium subspecies paratuberculosis (MAP) continues. The response to antitumor necrosis factor treatments suggests that, if relevant at all, MAP is not acting as a conventional pathogen. However, there is increased colonization by MAP in CD, and there is evidence that it could have an indirect effect mediated by the suppression of macrophage function. UC relapse is frequently associated with infection by pathogens, but there is less evidence for involvement of a specific bacterial species. Poor barrier integrity followed by an inflammatory reaction to bacterial components, with chronicity maintained by an autoimmune process, seems a plausible pathogenic model. Bacterial theories of pathogenesis are now becoming testable by targeted therapeutic interventions.

The growing incidence and severity of Clostridium difficile infection in inpatient and outpatient settings

Clostridium difficile infection (CDI) is a leading cause of nosocomial infections, with disease severity ranging from mild diarrhea to fulminant colitis. The incidence and severity of CDI has been on the rise over the last 10-20 years, with CDI being increasingly described outside healthcare settings and in populations previously thought to be at low risk. There has also been an increase in the morbidity, mortality and economic burden associated with CDI in the last several years. This increasing incidence and severity is thought to be at least partially due to frequent antibiotic use and the emergence of a hypervirulent C. difficile strain.

Prevalence and clinical impact of endoscopic pseudomembranes in patients with inflammatory bowel disease and Clostridium difficile infection

BACKGROUND AND AIM

Limited data suggests that pseudomembranes are uncommon in patients with inflammatory bowel disease (IBD) and C. difficile associated disease (CDAD), but the reason for this is unknown. We aimed to evaluate the rate of pseudomembranes in this population, identify predictive factors for pseudomembranes' presence and assess its clinical impact.

METHODS

This was a sub-study of a retrospective European Crohn's & Colitis Organization (ECCO) multi-center study on the outcome of hospitalized IBD patients with C. difficile. The present study included only patients who underwent lower endoscopy during hospitalization, and compared demographic and clinical parameters in the group of patients with discernable pseudomembranes versus those without.

RESULTS

Out of 155 patients in the original cohort, 93 patients underwent lower endoscopy and constituted the study population. Endoscopic pseudomembranes were found in 12 (13%) of these patients. Patients with pseudomembranes presented more commonly with fever (p=0.02) compared to patients without pseudomembranes. No difference between the two groups was found with respect to the use of immunosuppressant drugs, background demographics or disease characteristics. Neither was there a difference between the group with or without pseudomembranes in the frequency of severe adverse clinical outcome or in the duration of hospitalization. On multi-variate analysis the presence of fever remained independently associated with the finding of pseudomembranes (OR 6, 95% CI 1.2-32, p=0.03).

CONCLUSIONS

This study documents that hospitalized IBD patients with CDAD have low rate of endoscopic pseudomembranes, which is not accounted for by the use of immunosuppressant drugs. IBD patients with CDAD and discernable pseudomembranes more commonly present with fever, but their clinical outcome is similar to patients without pseudomembranes.

99th Dahlem conference on infection, inflammation and chronic inflammatory disorders: host-microbe interactions in the gut: target for drug therapy, opportunity for drug discovery

The commensal microbiota, most of which resides in the gut, is an environmental regulator of mucosal and systemic immune maturation. Epidemiological studies suggest that changes in the microbiota may represent a link between a modern lifestyle and risk of certain immuno-allergic diseases. This suggests that the microbiota is an appropriate target for therapy or prophylaxis, the rationale for which is addressed here using inflammatory bowel disease as an example. It is also evident from comparative studies of germ-free and conventionally colonized animals that the microbiota is a source of regulatory signals for full development of the host. In some instances these signals have been defined molecularly, and may be suitable for exploitation in novel drug discovery. Most of the versatile drugs in common usage today were derived originally from living matter in the wider environment; could it be time to mine new drugs from microbial-derived signalling molecules in the inner environment of the gut? Several examples illustrate the potential of the gut microbiota as a rich repository from which bioactives with immunological impact can be mined, and translated to human health care or to animal husbandry.

Genome analysis of the Clostridium difficile phage PhiCD6356, a temperate phage of the Siphoviridae family

The temperate phages PhiCD6356 and PhiCD6365 were isolated and characterised following mitomycin C induction of 43 Clostridium difficile strains. Both phages belong to the Siphoviridae family and have genome sizes of 37,664 bp for PhiCD6356 based on sequence data and approximately 50 kb for PhiCD6365 based on restriction analysis. Protein analysis revealed similar protein profiles and indicated posttranslational processing of the PhiCD6356 major capsid protein. The genome sequence of PhiCD6356 is substantially different from other previously reported phage sequences and a putative function could be assigned to only 21 out of 59 predicted open reading frames. However, the genome organisation closely resembles that of other members of the Siphoviridae family which infect low GC-content Gram-positive bacteria. The modular organisation, genome synteny, presence of cohesive ends and posttranslational processing of the capsid protein suggest PhiCD6356 is a member of the proposed Sfi21-like genera. To our knowledge, this report represents the first C. difficile phage of the Siphoviridae family to be sequenced.

Clostridium difficile infection and inflammatory bowel disease

The importance of Clostridium difficile (C. difficile) infection amongst patients with inflammatory bowel disease (IBD) is increasingly being recognized. Recent studies have demonstrated a concerning trend towards increased rates of infection, morbidity, mortality and health costs, and guidelines now promote testing for C. difficile in IBD patients experiencing a relapse. This critical review focuses on the epidemiology, risk factors, pathogenesis, treatment options and outcomes associated with C. difficile infection in patients with IBD.

Ulcerative colitis practice guidelines in adults: American College Of Gastroenterology, Practice Parameters Committee

Guidelines for clinical practice are aimed to indicate preferred approaches to medical problems as established by scientifically valid research. Double-blind placebo controlled studies are preferable, but compassionate-use reports and expert review articles are used in a thorough review of the literature conducted through Medline with the National Library of Medicine. When only data that will not withstand objective scrutiny are available, a recommendation is identified as a consensus of experts. Guidelines are applicable to all physicians who address the subject regardless of specialty training or interests and are aimed to indicate the preferable but not necessarily the only acceptable approach to a specific problem. Guidelines are intended to be flexible and must be distinguished from standards of care, which are inflexible and rarely violated. Given the wide range of specifics in any health-care problem, the physician must always choose the course best suited to the individual patient and the variables in existence at the moment of decision. Guidelines are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee and approved by the board of trustees. Each has been intensely reviewed and revised by the Committee, other experts in the field, physicians who will use them, and specialists in the science of decision analysis. The recommendations of each guideline are therefore considered valid at the time of composition based on the data available. New developments in medical research and practice pertinent to each guideline will be reviewed at a time established and indicated at publication to assure continued validity. The recommendations made are based on the level of evidence found. Grade A recommendations imply that there is consistent level 1 evidence (randomized controlled trials), grade B indicates that the evidence would be level 2 or 3, which are cohort studies or case-control studies. Grade C recommendations are based on level 4 studies, meaning case series or poor-quality cohort studies, and grade D recommendations are based on level 5 evidence, meaning expert opinion.

Secondary pouchitis: those with identifiable etiopathogenetic or triggering factors

Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the surgical treatment of choice for the majority of patients with medically refractory ulcerative colitis (UC) or UC with dysplasia, or familial adenomatous polyposis. Various forms of pouchitis frequently occur after surgery. In fact, pouchitis is the most frequent long-term complication of IPAA in patients with UC, with a cumulative prevalence of up to 50%. The etiology and pathogenesis of pouchitis are not entirely clear. It is generally believed that the initiation and development of the disease process of pouchitis is associated with dysbiosis of pouch reservoir, as evidenced by a favorable response to antibiotic therapy. However, the majority of the patients do not show identifiable etiopathogenetic or triggering factors, therefore being labeled to have idiopathic pouchitis. In contrast, a subgroup of patients, particularly those with antibiotic-refractory pouchitis, may have obvious triggering factors for disease flare-up and progression and may be considered to have secondary pouchitis. Therefore, pouchitis can be classified on the basis of etiology into idiopathic and secondary causes. Approximately 20-30% of patients who present with chronic pouchitis have secondary identifiable and triggering factors, including cytomegalovirus or Clostridium difficile infection, ischemia, concurrent immune-mediated disorders, radiation, collagen deposition, and use of nonsteroidal anti-inflammatory drugs. Careful evaluation of these secondary causes of pouchitis that may contribute to resistance to antibiotics should be performed before the introduction of next-line medical therapy.

Clostridium difficile and inflammatory bowel disease

The past decade has seen an alarming increase in the burden of disease associated with Clostridium difficile. Several studies have now demonstrated an increasing incidence of C difficile infection in patients with inflammatory bowel disease (IBD) with a more severe course of disease compared with the non-IBD population. This article summarizes the available literature on the impact of C difficile infection on IBD and discusses the various diagnostic testing and treatment options available. Also reviewed are clinical situations specific to patients with IBD that are important for the treating physician to recognize.

A role for Campylobacter jejuni-induced enteritis in inflammatory bowel disease?

The inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, are T cell-mediated diseases that are characterized by chronic, relapsing inflammation of the intestinal tract. The pathogenesis of IBD involves the complex interaction between the intestinal microflora, host genetic and immune factors, and environmental stimuli. Epidemiological analyses have implicated acute bacterial enteritis as one of the factors that may incite or exacerbate IBD in susceptible individuals. In this review, we examine how interactions between the common enteric pathogen Campylobacter jejuni (C. jejuni), the host intestinal epithelium, and resident intestinal microflora may contribute to the pathogenesis of IBD. Recent experimental evidence indicates that C. jejuni may permit the translocation of normal, noninvasive microflora via novel processes that implicate epithelial lipid rafts. This breach in intestinal barrier function may, in turn, prime the intestine for chronic inflammatory responses in susceptible individuals. Insights into the interactions between enteric pathogens, the host epithelia, and intestinal microflora will improve our understanding of disease processes that may initiate and/or exacerbate intestinal inflammation in patients with IBD and provide impetus for the development of new therapeutic approaches for the treatment of IBD.

Clostridium difficile and inflammatory bowel disease

The past decade has seen an alarming increase in the burden of disease associated with Clostridium difficile. Several studies have now demonstrated an increasing incidence of C difficile infection in patients with inflammatory bowel disease (IBD) with a more severe course of disease compared with the non-IBD population. This article summarizes the available literature on the impact of C difficile infection on IBD and discusses the various diagnostic testing and treatment options available. Also reviewed are clinical situations specific to patients with IBD that are important for the treating physician to recognize.