A prospective study of first attacks of inflammatory bowel disease and non-relapsing colitis. Microbiologic findings

Challenges in the diagnosis of ulcerative colitis with concomitant bacterial infections and chronic infectious colitis

Ulcerative colitis (UC) is a chronic inflammation of the large bowel characterized by diarrhea and a negative stool culture. However, several enteropathogens have been implicated as causative agents in UC. The differentiation between chronic infectious colitis (IC) and UC with concurrent infection is difficult owing to their similar clinical presentations. The study aimed to explore the presentations and diagnostic clues that enable differentiation between UC with concomitant infections and chronic IC. The study included 17 UC patients with a bacterial infection and 46 with chronic IC. The UC patients (47 ± 19 years) were younger than the chronic IC patients (58 ± 20 years) (P = 0.022). Bloody diarrhea was more common in UC than in chronic IC (58.8% vs 10.9%, P < 0.001). Previous antibiotic usage was a risk factor for chronic IC (5.9% vs 32.6%, P = 0.031). Malignancy was a common comorbidity of chronic IC (5.9% vs 34.8%, P = 0.022). UC patients had lower antibiotic response rates than chronic IC patients (60.0% vs 87.2%, P = 0.026). Aeromonas species and Clostridium difficile were common in both groups. Histological features of cryptitis and crypt abscess were useful in the diagnosis of UC (P = 0.052 and P = 0.016, respectively). Bloody diarrhea in a young adult, decreased response to antibiotic treatment, and results of endoscopy with biopsy are important features in the diagnosis of UC with bacterial infection.

Acute Infectious Gastroenteritis Potentiates a Crohn's Disease Pathobiont to Fuel Ongoing Inflammation in the Post-Infectious Period

Crohn’s disease (CD) is a chronic inflammatory condition of diverse etiology. Exposure to foodborne pathogens causing acute gastroenteritis produces a long-term risk of CD well into the post-infectious period but the mechanistic basis for this ongoing relationship to disease onset is unknown. We developed two novel models to study the comorbidity of acute gastroenteritis caused by Salmonella Typhimurium or Citrobacter rodentium in mice colonized with adherent-invasive Escherichia coli (AIEC), a bacterial pathobiont linked to CD. Here, we show that disease activity in the post-infectious period after gastroenteritis is driven by the tissue-associated expansion of the resident AIEC pathobiont, with an attendant increase in immunopathology, barrier defects, and delays in mucosal restitution following pathogen clearance. These features required AIEC resistance to host defense peptides and a fulminant inflammatory response to the enteric pathogen. Our results suggest that individuals colonized by AIEC at the time of acute infectious gastroenteritis may be at greater risk for CD onset. Importantly, our data identify AIEC as a tractable disease modifier, a finding that could be exploited in the development of therapeutic interventions following infectious gastroenteritis in at-risk individuals.

Western societies have a disproportionately high rate of inflammatory bowel disease (IBD), with growing incidence especially in the adolescent population. A large body of evidence supports the view that bacteria in the gut participate in the pathophysiology of human bowel diseases. The unifying concept is chronic inflammation that is driven by microbial stimulation of the mucosal immune system. However, the mechanisms by which pathogenic or commensal microbes work in concert with each other and with host responses to perpetuate this inflammation is not well known. Adherent-invasive E. coli (AIEC) are Crohn’s disease (CD)-associated bacteria that are implicated in disease pathology. AIEC are pro-inflammatory and may play a central role in maintaining chronic inflammation in response to other CD risk factors, such as acute infectious gastroenteritis. Here, we show that indeed, acute infectious gastroenteritis creates an inflammatory environment in the gut that drives AIEC expansion and worsens disease severity. The increase in disease severity strictly correlates with this AIEC bloom because blocking this bloom by sensitizing AIEC to host defenses also improves the health status of the host. The long time period between recovery from acute gastroenteritis and new onset CD may allow for targeted interventions to mitigate the risk of CD in AIEC-positive individuals.

Seasonal variations in onset and exacerbation of inflammatory bowel diseases in children

BACKGROUND

Studies have suggested that inflammatory bowel diseases (IBD) follow a seasonal pattern with regard to their onset and exacerbations. The aim of this study is to determine if there is any seasonal pattern to the onset and exacerbation of IBD in the pediatric population and if the birth of children diagnosed with IBD follows a seasonal pattern.

METHODS

Patients between the ages of 1 and 21 years and with a diagnosis of IBD established between July 1992 and July 2012 were included. Their onset and exacerbations of IBD (year and season) were recorded. The birth dates of the patients were aggregated to determine whether a seasonal birth pattern existed amongst them.

RESULTS

A total of 170 children were included in this study; 34% of patients had their onset in the fall and 19% of them had their onset in the summer. The total number of documented exacerbations was 358 and the median number of exacerbations was two, with a range of 1-11. IBD exacerbations were generally uniformly distributed throughout the year. We did not observe any specific season where children with IBD tended to be born.

CONCLUSIONS

Our data suggests that the onset of symptoms of IBD tends to have a seasonal trend with the highest incidence in the fall. However, we did not observe any association between seasonality and exacerbations in the pediatric population. Moreover, there was no specific season in which children with IBD tended to be born in greater numbers.

The intestinal microbiota dysbiosis and Clostridium difficile infection: is there a relationship with inflammatory bowel disease?

Gut microbiota is a compilation of microorganisms dwelling in the entire mammalian gastrointestinal tract. They display a symbiotic relationship with the host contributing to its intestinal health and disease. Even a slight fluctuation in this equipoise may be deleterious to the host, leading to many pathological conditions like Clostridium difficile infection or inflammatory bowel disease (IBD). In this review, we focus on the role of microbial dysbiosis in initiation of C. difficile infection and IBD, and we also touch upon the role of specific pathogens, particularly C. difficile, as causative agents of IBD. We also discuss the molecular mechanisms activated by C. difficile that contribute to the development and exacerbation of gastrointestinal disorders.

Endoscopic assessment of inflammatory bowel disease: colonoscopy/esophagogastroduodenoscopy

Endoscopy plays an important role in the initial diagnosis of IBD, including the evaluation of disease severity, activity, and extent. The implications of complete mucosal healing further confirm the function of endoscopy in the follow-up of IBD patients. The use of therapeutic endoscopy, for example stricture dilatation, can avoid the need for bowel resection. Modalities such as capsule endoscopy, EUS, NBI, CE, and other emerging techniques are likely to have an increasing role in the management of IBD, particularly in the area of dysplasia surveillance and treatment.

Helicobacter bilis colonization enhances susceptibility to Typhlocolitis following an inflammatory trigger

BACKGROUND

Aberrant mucosal immune responses to antigens of the resident microbiota are a significant cause of inflammatory bowel diseases (IBD), as are genetic and environmental factors. Previous work from our laboratory demonstrated that Helicobacter bilis colonization of immunocompetent, defined microbiota mice induced antigen-specific immune responses to the resident microbiota, yet these mice failed to develop colitis, suggesting that the immunological provocation induced by H. bilis alone was insufficient to induce disease.

AIM

The purpose of this study was to test the hypothesis that the introduction of a bacterial provocateur such as H. bilis enhances the host's susceptibility to IBD following an inflammatory event.

METHODS

Defined microbiota (DM) mice colonized with H. bilis were administered low dose (1.5%) dextran sodium sulfate (DSS) in drinking water for 5 days followed by a 4-day restitution period. Severity of lesions was assessed grossly and microscopically. Differential expression of select mucosal genes and histopathologic lesions was characterized.

RESULTS

Helicobacter bilis colonization increased the severity of intestinal inflammation induced by an inflammatory trigger in the form of low-dose DSS. An analysis of the molecular and cellular mechanisms associated with H. bilis colonization revealed significant increases in expression of mucosal genes associated with lymphocyte activation and inflammatory cell chemotaxis as well as increased infiltration of mucosal macrophages and T cells in mice colonized with H. bilis prior to DSS treatment versus DSS treatment alone.

CONCLUSIONS

These results indicate that prior colonization with H. bilis heightens the host's sensitivity to enteric inflammation by altering mucosal homeostasis and initiating immune cell activation and migration.

The Asia-Pacific consensus on ulcerative colitis

Inflammatory bowel disease (IBD) is increasing in many parts of the Asia-Pacific region. There is a need to improve the awareness of IBD and develop diagnostic and management recommendations relevant to the region. This evidence-based consensus focuses on the definition, epidemiology and management of ulcerative colitis (UC) in Asia. A multi-disciplinary group developed the consensus statements, reviewed the relevant literature, and voted on them anonymously using the Delphi method. The finalized statements were reviewed to determine the level of consensus, evidence quality and strength of recommendation. Infectious colitis must be excluded prior to diagnosing UC. Typical histology and macroscopic extent of the disease seen in the West is found in the Asia-Pacific region. Ulcerative colitis is increasing in many parts of Asia with gender distribution and age of diagnosis similar to the West. Extra-intestinal manifestations including primary sclerosing cholangitis are rarer than in the West. Clinical stratification of disease severity guides management. In Japan, leukocytapheresis is a treatment option. Access to biologic agents remains limited due to high cost and concern over opportunistic infections. The high endemic rates of hepatitis B virus infection require stringent screening before initiating immune-suppressive agents. Vaccination and prophylactic therapies should be initiated on a case-by-case basis and in accordance with local practice. Colorectal cancer complicates chronic colitis. A recent increase in UC is reported in the Asia-Pacific region. These consensus statements aim to improve the recognition of UC and assist clinicians in its management with particular relevance to the region.

Increased short- and long-term risk of inflammatory bowel disease after salmonella or campylobacter gastroenteritis

BACKGROUND & AIMS

Various commensal enteric and potentially pathogenic bacteria may be involved in the pathogenesis of inflammatory bowel diseases (IBD). We compared the risk of IBD between a cohort of patients with documented Salmonella or Campylobacter gastroenteritis and an age- and gender-matched control group from the same population in Denmark.

METHODS

We identified 13,324 patients with Salmonella/Campylobacter gastroenteritis from laboratory registries in North Jutland and Aarhus counties, Denmark, from 1991 through 2003, and 26,648 unexposed controls from the same counties. Of these, 176 exposed patients with IBD before the infection, their 352 unexposed controls, and 80 unexposed individuals with IBD before the Salmonella/Campylobacter infection were excluded. The final study cohort of 13,148 exposed and 26,216 unexposed individuals were followed for up to 15 years (mean, 7.5 years).

RESULTS

A first-time diagnosis of IBD was reported in 107 exposed (1.2%) and 73 unexposed individuals (0.5%). By age, gender, and comorbidity adjusted Cox proportional hazards regression analysis, the hazard ratio (95% confidence interval) for IBD was 2.9 (2.2-3.9) for the whole period and 1.9 (1.4-2.6) if the first year after the Salmonella/Campylobacter infection was excluded. The increased risk in exposed subjects was observed throughout the 15-year observation period. The increased risk was similar for Salmonella (n = 6463) and Campylobacter (n = 6685) and for a first-time diagnosis of Crohn's disease (n = 47) and ulcerative colitis (n = 133).

CONCLUSIONS

In our population-based cohort study with complete follow-up, an increased risk of IBD was demonstrated in individuals notified in laboratory registries with an episode of Salmonella/Campylobacter gastroenteritis.

Impact of Clostridium difficile infection on pediatric inflammatory bowel disease

OBJECTIVES

To determine the prevalence of and explore possible differences in the risk for and symptoms of Clostridium difficile infection between patients with and without inflammatory bowel disease (IBD).

STUDY DESIGN

Stool specimens from subjects with and without IBD were evaluated for the presence of C difficile toxins. Demographic information, diagnosis, anatomic location, disease activity, IBD therapy, hospitalizations, and antibiotic and proton pump inhibitor (PPI) exposures were recorded.

RESULTS

A total of 193 specimens were collected from 81 patients with IBD and 112 patients without IBD. The prevalence of C difficile infection was significantly greater in the patients with IBD than in those without IBD (P = .004; chi2 = 0.003; odds ratio = 3.3; 95% confidence interval = 1.5 to 7.6). In the patients with IBD, the prevalence of active disease was significantly greater in the C difficile-infected patients than in the uninfected patients (P < .0001). Colonic involvement was found in all patients with IBD. The specific type of IBD, IBD therapy, and antibiotic and PPI exposures that predisposed patients with IBD to C difficile infection were not identified, whereas hospitalization was significantly more frequent in the patients without IBD (P = .025).

CONCLUSIONS

Our findings indicate that in children, IBD is associated with an increased prevalence of C difficile infection. The specific risk factors reported in adults were not identified in these children, suggesting the possible involvement of other mechanisms for acquiring the pathogen.

Enteric infections and diagnostic testing

PURPOSE OF REVIEW

Gastrointestinal pathogens profoundly affect human health and well being. The provider's ability to render optimal care often highly depends on diagnostic microbiologic support. We aim to provide a clinically pertinent assessment of the current state of our ability to diagnose human gastrointestinal pathogens and describe (and decry) the unsophistication of many current diagnostic methods and strategies.

RECENT FINDINGS

Recent advances involve improved stool polymerase chain reaction assays and application of this technology to a broader panel of pathogens, stool antigen assays, and improved culture techniques, but there is little penetration of such diagnostic advances into clinical practice. Many such techniques remain limited to research or epidemiologic use and are not typically available in the clinical laboratory.

SUMMARY

Multiple clinical and laboratory factors need to be considered when attempting to diagnose the wide variety of gastrointestinal pathogens afflicting humans. Careful interpretation of diagnostic tests with attention to the population studied and the characteristics of each test is necessary.

Antibiotic-associated diarrhea: candidate organisms other than Clostridium difficile

BACKGROUND/AIMS

The direct toxic effects of antibiotics on the intestine can alter digestive functions and cause pathogenic bacterial overgrowth leading to antibiotic-associated diarrhea (AAD). Clostridium difficile (C. difficile) is widely known to be responsible for 10 approximately 20% of AAD cases. However, Klebsiella oxytoca, Clostridium perfringens, Staphylococcus aureus, and Candida species might also contribute to AAD.

METHODS

We prospectively analyzed the organisms in stool and colon tissue cultures with a C. difficile toxin A assay in patients with AAD between May and December 2005. In addition, we performed the C. difficile toxin A assays using an enzyme-linked fluorescent assay technique. Patients were enrolled who had diarrhea with more than three stools per day for at least 2 days after the initiation of antibiotic treatment for up to 6 approximately 8 weeks after antibiotic discontinuation.

RESULTS

Among 38 patients (mean age 59 +/- 18 years, M:F =18:20), the organism isolation rates were 28.9% (11/38) for stool culture, 18.4% (7/38) for colon tissue cultures and 13.2% (5/38) for the C. difficile toxin A assay. The overall rate of identification of organisms was 50.0% (19/38). Of the five patients that had a positive result by the C. difficile toxin A assay, two had no organism isolated by the stool or colon tissue culture. The organisms isolated from the stool cultures were C difficile (4), Klebsiella pneumoniae (K. pneumoniae) (3), Candida species (3), and Staphylococcus aureus (1). C. difficile (4) and K. pneumoniae (3) were isolated from the colon tissue culture.

CONCLUSIONS

For C. difficile negative AAD patients, K. pneumoniae, Candida species and Staphylococcus aureus were found to be potential causative organisms.

Infections and IBD

An interaction between infection and IBD was identified soon after Crohn's disease and ulcerative colitis were first described. Since then it has become apparent that infectious agents are involved with both the etiopathogenesis and clinical course of IBD on several levels. Whilst our understanding of this interplay is incomplete, it is clear that infections can initiate both the onset and relapse of IBD. Furthermore, the disease process itself predisposes patients to certain infections, and many drugs used to treat IBD also increase the risk of infectious complications. Attempts to establish the relative infectious risks associated with the drugs used to treat IBD remain in an early stage; but it seems that the greatest risks relate to the combined use of immunomodulating agents rather than to individual drugs. The risk of infections in patients with IBD might also be exacerbated by underuse of, and perhaps substandard response to, vaccinations. It is axiomatic that physicians treating patients with IBD must be aware of these infectious risks and of strategies to minimize them. Meanwhile, intriguing advances in the use of parasitic agents as a treatment for ulcerative colitis and Crohn's disease have introduced a new angle to the interplay between infections and IBD.

Herpes simplex virus colitis complicating ulcerative colitis: A case report and brief review on superinfections

In patients with inflammatory bowel disease herpes simplex virus infection has been described as a major cause of morbidity and mortality, especially in immunocompromised individuals. Here we present the case of a 35-year old woman with an exacerbation of ulcerative colitis caused by herlpes simplex virus infection (HSV-2). The diagnosis was confirmed histologically following subtotal colectomy. After intravenous treatment with aciclovir for 2 weeks postoperative hematochezia stopped. Herpes simplex virus colitis is a rare but potentially fatal complication of immunosuppressive treatment in patients with inflammatory bowel disease. Prompt diagnosis and efficient antiviral therapy are mandatory to improve prognosis.

Acute gastroenteritis is followed by an increased risk of inflammatory bowel disease

BACKGROUND & AIMS

Bacterial intestinal infections have been implicated as a possible cause of exacerbation of inflammatory bowel disease (IBD). We explored the relationship between infectious gastroenteritis and the occurrence of IBD using data from the General Practice Research Database.

METHODS

A cohort of patients aged 20-74 years with an episode of acute infectious gastroenteritis (n = 43,013) was identified. From the same source population, an age-, sex-, and calendar time-matched control group free of gastroenteritis was sampled (n = 50,000). Both cohorts were followed up for a mean duration of 3.5 years.

RESULTS

The estimated incidence rate of IBD was 68.4 per 100,000 person-years after an episode of gastroenteritis and 29.7 per 100,000 person-years in the control cohort. The hazard ratio of IBD was 2.4 (95% confidence interval [CI], 1.7-3.3) in the gastroenteritis cohort compared with the control cohort, and the excess risk was greater during the first year after the infective episode (hazard ratio, 4.1; 95% CI, 2.2-7.4). The relative risk of developing Crohn's disease in the gastroenteritis cohort was greater than that of ulcerative colitis, especially during the first year after the infective episode (hazard ratio, 6.6; 95% CI, 1.9-22.4).

CONCLUSIONS

Our results are compatible with the hypothesis that infectious agents causing an episode of infectious gastroenteritis could play a role in the initiation and/or exacerbation of IBD.

Seasonal variations in onset of symptoms in Crohn's disease

BACKGROUND

Seasonal variations in onset of symptoms have been reported in ulcerative colitis but not in Crohn's disease. AIM.: To investigate whether our inflammatory bowel diseases patients presented seasonal variations in onset of symptoms.

PATIENTS AND METHODS

Patients with a diagnosis of inflammatory bowel diseases established between 1995 and May 2004, and consecutively observed from June 2003 to May 2004, were included in the study. Onset of symptoms (year, season and month) was recorded. Expected onsets with a uniform distribution during the year were calculated and compared to observed onsets.

STATISTICAL ANALYSIS

chi-square test, odds ratio (95% confidence interval).

RESULTS

Overall 425 inflammatory bowel diseases patients were enrolled. Onset of symptoms (year and season) was established in 353/425 patients (83%; 150 Crohn's disease; 203 ulcerative colitis). Onset of symptoms in inflammatory bowel diseases patients as a whole occurred more frequently in spring-summer compared to autumn-winter (odds ratio 1.39; 95% confidence interval 1.03-1.87; p<0.03). This variation was observed in Crohn's disease (odds ratio 1.59; 95% confidence interval 1.00-2.51; p<0.05) and a similar trend, although not significant, was observed in ulcerative colitis (odds ratio 1.27; 95% confidence interval 0.86-1.88; p=0.27).

CONCLUSIONS

These data indicate that onset of Crohn's disease symptoms occurred more frequently during spring-summer. A similar trend was observed in ulcerative colitis. Environmental factors, such as associated infections, smoking, use of drugs and seasonal changes in immune function may be responsible for triggering the clinical onset of inflammatory bowel diseases.

Serum procalcitonin differentiates inflammatory bowel disease and self-limited colitis

BACKGROUND

The distinction between idiopathic inflammatory bowel disease (IBD) and infectious, usually self-limited enterocolitis is still a diagnostic dilemma. Procalcitonin (PCT) is the prohormone of calcitonin and is considered a specific marker of bacterial infection. The aim of this prospective study was to determine the value of PCT in differentiating flares of IBD from self-limited colitis. In addition, because standard laboratory inflammatory parameters are poorly correlated with disease activity in IBD, the relation between PCT levels and disease activity was investigated.

METHODS

A total of 76 patients (26 Crohn's disease, CD; 25 ulcerative colitis, UC; and 25 patients with self-limited enterocolitis) were enrolled. Serum levels of PCT were measured by a sandwich immunoluminometric assay. C-reactive protein (CRP) levels, white blood cell counts, and stool cultures were obtained from all patients. Disease activity was assessed by the Crohn's disease activity index (CDAI) and the Truelove index for CD and UC, respectively.

RESULTS

Patients with self-limited enterocolitis showed significantly higher PCT levels when compared with IBD patients (0.36 ng/mL, range 0.18-1.7 vs 0.10 ng/mL, range 0.08 0.5, p < 0.001). For a PCT value of > or =0.4, the sensitivity for self-limited colitis was 92% and specifity 96%. The positive predictive value (PPV) for self-limited colitis was 96%, whereas the negative predictive value (NPV) was 93%. In IBD patients, PCT levels were in the normal range although significantly higher in active disease when compared with inactive disease (0.13 ng/mL, range 0.08-0.5 vs 0.09 ng/mL, range 0.08-0.15, p < 0.001). This difference was less pronounced for CD (0.11 ng/mL, range 0.08-0.2 vs 0.09 ng/mL, range 0.08-0.15, p < 0.05) than for UC (0.14 ng/mL, range 0.08-0.5 vs 0.09 ng/mL, range 0.08-0.11, p < 0.01). In CD, PCT levels correlated significantly 0.5, p < 0.01). with the CDAI (r =0.05, p <0.01).

CONCLUSIONS

The measurement of PCT offers two diagnostic options in IBD. Supranormal levels indicate self-limited enterocolitis. Furthermore, although within the normal range in IBD, PCT levels may serve as a new serological marker of disease activity.

Klebsiella oxytoca as an agent of antibiotic-associated hemorrhagic colitis

BACKGROUND & AIMS

Klebsiella oxytoca has been isolated from stools and colonic biopsy specimens of patients with Clostridium difficile-negative antibiotic-associated hemorrhagic colitis (AAHC), but the pathogenic role of the germ has not been established. The purpose of this study was to investigate the presence of K. oxytoca in patients with AAHC from a prospective cohort of patients with acute colitis, and to test the cytotoxicity on HEp-2 cells of K. oxytoca strains from patients with AAHC and healthy carriers.

METHODS

Colonic biopsy specimens and a sample of colonic fluid from 93 consecutive patients with acute colitis were cultured on selective media for 7 established pathogens and K. oxytoca. The 2 K. oxytoca strains isolated in the 4 patients with C. difficile-negative AAHC of this cohort and 105 additional K. oxytoca strains from patients with C. difficile-negative AAHC (n = 15) and healthy carriers (n = 90) were tested for cytotoxicity using a HEp-2 cell culture assay.

RESULTS

K. oxytoca was isolated in 50% (2 of 4) of the patients of the prospective cohort with C. difficile-negative AAHC compared with 2% (1 of 41) of the patients with acute colitis caused by established pathogens (P = 0.02). The rate of cytotoxic strains of K. oxytoca was higher in patients with AAHC (82%) than in healthy carriers (42%, P = 0.003).

CONCLUSIONS

We conclude that K. oxytoca is isolated with a significant high rate in patients with C. difficile-negative AAHC, and that K. oxytoca strains from patients with AAHC are cytotoxic more frequently on HEp-2 cells than strains from healthy carriers. These results strengthen the hypothesis of a causative role of K. oxytoca in some of the patients with AAHC.

Indeterminate colitis

A diagnosis of Crohn's disease (CD) and ulcerative colitis (UC) is based on a combination of clinical, histologic, endoscopic, and radiologic data. The distinction between UC and CD can be difficult because of the lack of a differentiating single gold standard. Indeterminate colitis (IC) was introduced by pathologists for the diagnosis of surgical colectomy specimens showing an overlap between the features of UC and CD. The diagnosis of IC was based on macroscopic and microscopic features. The term indeterminate colitis is in recent years more widely applied to include all cases with endoscopic, radiographic, and histologic evidence of chronic inflammatory bowel disease confined to the colon, but without fulfilment of diagnostic criteria for UC and CD. As for UC and CD, the diagnosis of IC has therefore become a clinicopathologic diagnosis. IC is generally considered to be a temporary diagnosis. The clinical characteristics of patients with IC are, however, somewhat different from the characteristics of those with UC. Furthermore, serologic markers such as perinuclear antineutrophil cytoplasmic antibody and anti-Saccharomyces cerevisiae, which are strongly linked with UC and CD, are both negative in a subset of patients with IC. Therefore, the possibility that IC could be a separate entity must be investigated.

Role of infections in the manifestation or reactivation of inflammatory bowel diseases

The etiology of inflammatory bowel disease (IBD) is unknown. In addition to genetic and environmental factors, microorganisms have been discussed as possibly playing an important role. Recent reports in the literature do not suggest that a specific persistent infection causes IBD, but indicate that enteric pathogens could cause initial onset of IBD and are associated with reactivation of quiescent disease. Despite their self-limited character, these infections initiate a cascade of inflammatory events leading to chronic, relapsing disease in a genetically susceptible host ("hit-and-run" hypothesis). Epidemiological and microbiologic studies suggest that enteropathogenic microorganisms play a substantial role in the clinical initiation and relapses of IBD. However, similar to traveler's diarrhea, the frequency of infections in the first manifestation and in relapses of IBD is probably understated, due to the problems in detecting enteric pathogens. Thus microbiologic screening is helpful in patients with flares of IBD for optimal medical treatment.

Inflammatory bowel disease. 1. Origins, presentation, and course

The exact cause of inflammatory bowel disease remains undiscovered, but its destructive nature is clearly recognized. In this article, the authors summarize what is known about the pathogenesis and epidemiology of ulcerative colitis and Crohn's disease and how to distinguish between the two, both clinically and pathologically. They also describe disorders that may mimic inflammatory bowel disease. In part 2 of this article, beginning on page 86, the authors discuss some of the therapeutic options that are the commonly used as well as some that are investigational but show promise for patients with this chronic and relapsing disease.

Invasion of tissue culture cells by diarrhoeagenic strains of Escherichia coli which lack the enteroinvasive inv gene

Invasive Escherichia coli strains of certain serotypes invade by the same mechanism as the Shigella sp. It has been proposed that invasion of epithelial cells by EPEC strains may also occur; this is a previously overlooked property. In the present study E. coli strains isolated from patients with diarrhoea or ulcerative colitis, lacking the inv plasmid mediating classical invasion, but hybridizing with probes for different adhesins, were analyzed for their ability to invade HeLa and Caco-2 cells. The majority of strains invaded Caco-2 cells to a higher extent than HeLa cells. Adhesion to Caco-2 cells was a prerequisite for subsequent invasion of the cells but EAF, eae, EAgg and other known virulence factors were not sufficient to mediate invasion. In 8/9 E. coli strains invasion was enhanced after growth under iron restriction. Growth during anaerobic conditions did not influence subsequent invasion by E. coli strains whereas 6/9 strains had their invasive ability significantly decreased after growth in the presence of 1% glucose. The invasive process was inhibited by mannose but not by lactose, fucose or galactose. Our data indicate that strains of E. coli may invade Caco-2 cells by novel mechanisms which require adhesion to the cells but which differ from those of Salmonella sp., Yersinia sp., Shigella sp. and classical enteroinvasive E. coli.

Ulcerative colitis in children

Chronic nonspecific ulcerative colitis remains a disease of unknown etiology, although much new information continues to be gleaned from basic research and clinical trials. In most instances, ulcerative colitis responds to medical therapy. Selecting appropriate drug therapy for a specific child depends on the extent and severity of the colitis. This article summarizes the clinical information, diagnostic studies, and approaches to management that should be considered when evaluating a child for ulcerative colitis.

Anti-neutrophil cytoplasmic antibodies in chronic inflammatory bowel disease. Prevalence and diagnostic role

BACKGROUND

Anti-neutrophil cytoplasmic antibodies (ANCA), originally found to be associated with vasculitis, have been reported to be present in chronic inflammatory bowel disease. Most often the ANCA staining pattern is of the perinuclear type (p-ANCA), although nuclear and cytoplasmic stainings are seen. Single studies have shown some of the antibodies to react with lactoferrin or cathepsin G; however, most studies have not been able to determine a main antigenic specificity. We studied the prevalence of ANCA in sera from 155 patients with ulcerative colitis, 128 patients with Crohn's disease, and 51 patients with coeliac disease. The presence of ANCA was correlated to disease activity, extent, and age of onset of the diseases. Furthermore, we tried to characterize the antigen specificity by enzyme-linked immunosorbent assay (ELISA), using elastase, lactoferrin, myeloperoxidase, proteinase 3, and cathepsin G as antigens.

METHODS

The sera were screened for ANCA by indirect immunofluorescence. Anti-nuclear antibodies (ANA) were analysed on HEp2 cells, and ELISA for specific ANCA was performed using the antigens mentioned.

RESULTS

Most of the sera with positive immunofluorescence had the p-ANCA type of pattern. Seventy-eight of 155 (50.3%) of the patients with ulcerative colitis were ANCA-positive, compared with 31 of 128 (24.2%) of patients with Crohn's disease (p < 0.001). However, in the subgroup with Crohn's colitis, 16 of 44 (36.4%) were ANCA-positive. Only 4 of 51 patients (7.7%) with coeliac disease showed positive immunofluorescence (p < 0.001 compared with ulcerative colitis). Less than 10% of the samples were positive in the specific ELISA assays; thus other than the most well known granule proteins can be the target for ANCA in ulcerative colitis.

CONCLUSION

ANCA occur significantly more often in ulcerative colitis than in Crohn's disease. However, the prevalence of ANCA is rather high in Crohn's colitis. ANCA are thus of limited value in differentiating Crohn's colitis from ulcerative colitis. ANCA found in inflammatory bowel disease are different from those associated with vasculitis. The antigen(s) responsible remain to be determined.

Circulating granulocyte antibodies in first attacks of colitis

BACKGROUND

Antineutrophil cytoplasmic antibodies (ANCA) have recently been demonstrated in the sera of patients with inflammatory bowel disease (IBD).

METHODS

The presence of ANCA was studied in 107 sera obtained during 1 year from 48 patients with a first attack of IBD and in 33 such sera from 19 patients with infectious or infectious-type colitis (non-relapsing colitis (NRC)).

RESULTS

In 65% (31 of 48) of the IBD patients positive immunofluorescence reactivity against granulocytes was observed, compared with in 5% of the NRC patients. No significant difference in granulocyte reactivity was found either between patients with colonic Crohn's disease and those with ulcerative colitis or between active and inactive phases of the disease. Most of the sera showed a perinuclear immunofluorescence staining pattern (68%), in contrast to the classical cytoplasmic staining pattern seen in Wegener's granulomatosis. In sera obtained at the first visit from the 31 IBD patients with positive granulocyte reactivity a hitherto unknown antibody against beta-glucuronidase was found in 42%, whereas in 45% the specificity was not identified. Other antibodies, rarely seen, were directed against myeloperoxidase, lactoferrin, elastase, and cathepsin G. No antibody directed against lysozyme was detected.

CONCLUSIONS

Positive granulocyte reactivity practically excluded NRC and was seen in more than half of IBD patients. Antibodies against beta-glucuronidase were common, but still almost half of the antibodies remained unknown.

A prospective study of first attacks of inflammatory bowel disease and infectious colitis. Histologic course during the 1st year after presentation

To investigate the possibilities of differentiating between inflammatory bowel disease (IBD) and infectious colitis on histologic grounds, a prospective histologic study of 105 patients with a first attack of colitis was undertaken. Rectal biopsies were performed on four occasions during 1 year. The strongest predictor of IBD was basal plasmacytosis, followed by more than two vertical crypt branches per medium-power field, crypt distortion, villous mucosa, and mucosal atrophy. These signs were rarely found among patients with infectious colitis. Their frequency increased with the interval between initial symptoms and the first biopsy. To study the development of histologic features in the absence of treatment, the IBD patients were divided into groups depending on this interval. Focal or diffuse basal plasmacytosis increased from 38% in the group with an interval of 1-15 days to 89% in those who presented in 121-300 days, and crypt distortion from 0% to 78%, whereas absence of signs indicating IBD decreased from 62% to 11%. The presence of focal basal plasmacytosis seems to be the earliest sign of IBD. The frequency of histologic signs indicating IBD was maximal (88%) at the 1-week biopsy. After recovery, the basal plasmacytosis and villous mucosa decreased, whereas crypt distortion and mucosal atrophy remained unchanged. Early treatment did not prevent the appearance of any feature.

A prospective study of first attacks of inflammatory bowel disease and infectious colitis. Clinical findings and early diagnosis

In 105 patients with a first attack of colitis, clinical, microbiologic, laboratory, and histologic features were studied prospectively with the aim of differentiating inflammatory bowel disease (IBD) from infectious colitis as early as possible. Of the patients who proved to have IBD the mode of onset of diarrhoeal symptoms was insidious in 56% and non-insidious in 44%, whereas in 81% of those who proved to have infectious colitis the onset was acute. Most patients with infectious colitis presented within 1 week, had early fever, and did not show histologic features characteristic of IBD. Most IBD patients with a more acute onset had clinical warning signs of IBD such as slight previous bowel symptoms, a late presentation time (> 1 week), and absence of early fever or had histologic features characteristic of IBD. These features were basal plasmacytosis, crypt distortion, more than two vertical crypt branches, villous mucosa, mucosal atrophy, epithelioid granuloma, and Paneth cell metaplasia. Moreover, 61% of the IBD patients with a non-insidious onset fell ill in connection with travelling abroad, gastrointestinal infection, or treatment with antibiotics. Knowledge of the above clinical and histologic factors will facilitate differentiation of IBD from infectious-type colitis.