In vitro inhibition activity of different bacteriocin-producing Escherichia coli against Salmonella strains isolated from clinical cases.

AIMS: To compare in vitro the inhibitory activity of four bacteriocin-producing Escherichia coli to a well-characterized panel of Salmonella strains, recently isolated from clinical cases in Switzerland. METHODS AND RESULTS: A panel of 68 nontyphoidal Salmonella strains was characterized by pulsed-field gel electrophoresis analysis and susceptibility to antibiotics. The majority of tested strains were genetically different, with 40% resistant to at least one antibiotic. E. coli Mcc24 showed highest in vitro activity against Salmonella (100%, microcin 24), followed by E. coli L1000 (94%, microcin B17), E. coli 53 (49%, colicin H) and E. coli 52 (21%, colicin G) as revealed using a cross-streak activity assay. CONCLUSIONS: Escherichia coli Mcc24, a genetically modified organism producing microcin 24, and E. coli L1000, a natural strain isolated from human faeces carrying the mcb-operon for microcin B17-production, were the most effective strains in inhibiting in vitro both antibiotic resistant and sensitive Salmonella isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: Due to an increasing prevalence of antibiotic resistant Salmonella strains, alternative strategies to fight these foodborne pathogens are needed. E. coli L1000 appears to be a promising candidate in view of developing biotechnological alternatives to antibiotics against Salmonella infections.

Malignancy and mortality in paediatric-onset inflammatory bowel disease: a 3-year prospective, multinational study from the paediatric IBD Porto group of ESPGHAN.

BACKGROUND: Risk benefit strategies in managing inflammatory bowel diseases (IBD) are dependent upon understanding the risks of uncontrolled inflammation vs those of treatments. Malignancy and mortality in IBD have been associated with disease-related inflammation and immune suppression, but data are limited due to their rare occurrence. AIM: To identify and describe the most common causes of mortality, types of cancer and previous or current therapy among children and young adults with paediatric-onset IBD. METHODS: Information on paediatric-onset IBD patients diagnosed with malignancy or mortality was prospectively collected via a survey in 25 countries over a 42-month period. Patients were included if death or malignancy occurred after IBD diagnosis but before the age of 26 years. RESULTS: In total, 60 patients were identified including 43 malignancies and 26 fatal cases (9 due to cancer). Main causes of fatality were malignancies (n = 9), IBD or IBD-therapy related nonmalignant causes (n = 10; including 5 infections), and suicides (n = 3). Three cases, all fatal, of hepatosplenic T-cell lymphoma were identified, all were biologic-naïve but thiopurine-exposed. No other haematological malignancies were fatal. The 6 other fatal cancer cases included 3 colorectal adenocarcinomas and 3 cholangiocarcinomas (CCAs). Primary sclerosing cholangitis (PSC) was present in 5 (56%) fatal cancers (1 colorectal carcinoma, 3 CCAs and 1 hepatosplenic T-cell lymphoma). CONCLUSIONS: We report the largest number of paediatric-onset IBD patients with cancer and/or fatal outcomes to date. Malignancies followed by infections were the major causes of mortality. We identified PSC as a significant risk factor for cancer-associated mortality. Disease-related adenocarcinomas were a commoner cause of death than lymphomas.

Cytokines in stools of children with inflammatory bowel disease or infective diarrhoea.

AIMS: To determine the concentrations of interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF alpha) in stools from children. METHODS: Stool samples from 14 healthy children, 32 children with inflammatory bowel disease, and 23 children with acute diarrhoea were emulsified in an equal volume of phosphate buffered saline and then centrifuged to produce a clear supernatant fluid. IL-6 and TNF alpha were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: TNF alpha was detected in the stools of all 14 healthy children (12-130 pg/g stool), but IL-6 was detected only in three. Similar results were seen in children with inactive inflammatory bowel disease. Stool TNF alpha concentrations were raised in samples from children with active inflammatory bowel disease, but in most (11/18) of these samples IL-6 was undetectable. Stool samples contained a heat-labile factor which rapidly destroyed IL-6 immunoreactivity. Most children with diarrhoea had TNF alpha concentrations similar to those of healthy controls and most were also negative for IL-6. Three children with Shigella flexneri infection had extraordinarily high concentrations of both TNF alpha and IL-6 in their stools. CONCLUSIONS: There is constant low grade production of TNF alpha in the intestine of healthy people. Raised values are indicative of mucosal inflammation, but are not specific. Stool IL-6 is of little use in assessing mucosal inflammation because immunoreactivity is rapidly lost in stool samples.

Immunopathogenesis of chronic inflammatory bowel disease.

The aetiology and pathogenesis of chronic inflammatory bowel disease are unknown. However, there is circumstantial evidence that immune mechanisms may play a significant role in mediating the gut lesion and various systemic manifestations. The role of the cellular immune system, soluble mediators, including proinflammatory and immunoregulatory cytokines, humoral immunity and mucosal complement activation will be discussed.

Consensus guidelines of ECCO/ESPGHAN on the medical management of pediatric Crohn's disease.

Children and adolescents with Crohn's disease (CD) present often with a more complicated disease course compared to adult patients. In addition, the potential impact of CD on growth, pubertal and emotional development of patients underlines the need for a specific management strategy of pediatric-onset CD. To develop the first evidenced based and consensus driven guidelines for pediatric-onset CD an expert panel of 33 IBD specialists was formed after an open call within the European Crohn's and Colitis Organisation and the European Society of Pediatric Gastroenterolog, Hepatology and Nutrition. The aim was to base on a thorough review of existing evidence a state of the art guidance on the medical treatment and long term management of children and adolescents with CD, with individualized treatment algorithms based on a benefit-risk analysis according to different clinical scenarios. In children and adolescents who did not have finished their growth, exclusive enteral nutrition (EEN) is the induction therapy of first choice due to its excellent safety profile, preferable over corticosteroids, which are equipotential to induce remission. The majority of patients with pediatric-onset CD require immunomodulator based maintenance therapy. The experts discuss several factors potentially predictive for poor disease outcome (such as severe perianal fistulizing disease, severe stricturing/penetrating disease, severe growth retardation, panenteric disease, persistent severe disease despite adequate induction therapy), which may incite to an anti-TNF-based top down approach. These guidelines are intended to give practical (whenever possible evidence-based) answers to (pediatric) gastroenterologists who take care of children and adolescents with CD; they are not meant to be a rule or legal standard, since many different clinical scenario exist requiring treatment strategies not covered by or different from these guidelines.

[Gastroesophageal reflux in infants and children]. / Gastroösophagealer Reflux bei Säuglingen und Kindern.

Gastrooesophageal reflux is a common clinical condition in infancy and childhood. Evaluation and treatment are indicated if it is associated with complications such as failure to thrive, oesophagitis or pulmonary symptoms. Depending on the clinical symptoms, investigations may include pH-monitoring, upper gastrointestinal series and endoscopy. Gastrooesophageal reflux may be treated by parental reassurance, dietary advice, positional treatment, prokinetic agents and acid secretion inhibitors. Surgery is rarely indicated.

Immune mechanisms in chronic inflammatory bowel disease.

Crohn's disease and ulcerative colitis are chronic inflammatory bowel diseases of unknown etiology. However, there is circumstantial evidence that immune mechanisms play an important role in the pathogenesis of the intestinal lesion, and cytokines produced by lymphoid cells may be critical for the extraintestinal sequelae of the disease. In both Crohn's disease and ulcerative colitis, activation of macrophages seems to be a key feature. Increased production of the macrophage derived cytokines TNF-alpha, IL-1 and IL-6 have been reported in both diseases. Additionally in Crohn's disease, large numbers of activated T lymphocytes can be detected in the lamina propria and the T lymphocyte derived cytokines IL-2 and IFN-gamma are secreted by a higher number of lamina propria T lymphocytes in active Crohn's disease. However, this is not the case in ulcerative colitis. The increased number of activated T lymphocytes secreting IFN-gamma may be responsible for granuloma formation in Crohn's disease, as well as for MHC class II antigen expression on colonic epithelial cells. Lamina propria T lymphocytes seem to have lost their physiological unresponsiveness to several microbial antigens. All these observations suggest that Crohn's disease may be caused by hyperreaction of the local cellular immune system to numerous microbial and nutritional antigens normally present in the intestine. The factor inducing this immune dysregulation remains unknown. Cell-mediated immunity seems to be less important in ulcerative colitis, as activated T lymphocytes are only sparse within the inflamed mucosa, and the T lymphocyte derived cytokines IL-2 and IFN-gamma cannot be detected in the gut lesion or in the serum.(ABSTRACT TRUNCATED AT 250 WORDS)

The immunologic basis for celiac disease and related disorders.

Celiac disease is the classical food-sensitive enteropathy and is caused by an antigen-specific immunologic hypersensitivity response to gluten within the small intestinal mucosa. Antibody and T-cell hypersensitivity may play a role in vivo, but it is more likely that the primary problem is an inappropriate T-cell response to gluten. The deleterious effects of gluten in celiac patients can be completely explained by the immune-mediated alterations in upper small-intestinal mucosal shape; these alterations include the replacement of long villi and short crypts with short or absent villi and hyperplastic crypts. It is an extremely unusual disease in that it is highly linked to human leukocyte antigen (HLA)-DQ2, and CD4+ T-cell clones that recognize gluten in the context of DQ2 have been isolated from celiac mucosa lamina propria. HLA-DQ2 is commonly used in Whites, but the incidence of celiac disease varies greatly between different countries and with time, without any obvious explanation. Celiac disease is also unusual in that it has features of autoimmune disease. Patients with active disease have immunoglobulin (Ig)A antibodies in endomysium, an uncharacterized extracellular matrix protein, and the presence of these antibodies is very specific for this condition. However, because celiac disease is more common in IgA-deficient patients, the IgA antiendomysial antibodies are unlikely to be pathogenic.

Helicobacter pylori infection in recurrent abdominal pain.

BACKGROUND: Helicobacter pylori is associated with chronic gastritis and peptic ulcer in adults and in children. The purpose of the present study was to analyze the association of recurrent abdominal pain and H. pylori infection in children and to evaluate the efficacy of antimicrobial treatment in patients with evidence of infection. METHODS: The clinical and histopathologic findings in children who underwent diagnostic upper endoscopy for recurrent abdominal pain were analyzed retrospectively. Patients with evidence of infection with H. pylori were treated with a combination of omeprazole, amoxicillin, and clarithromycin. Efficacy of treatment was assessed using the 13C-urea-breath test. RESULTS: H. pylori was found in histopathologic sections of 29 (40%) of 73 patients undergoing diagnostic endoscopy for recurrent abdominal pain. Five children (17%) were of Swiss ethnic origin, and 24 (83%) were non-Swiss. All the infected patients had chronic gastritis and 4 (14%) had ulcerations in the duodenum. Treatment with omeprazole, amoxicillin, and clarithromycin resulted in eradication of the infection in all and in resolution of the clinical symptoms in 15 (80%) of 19 patients who had a follow-up examination. CONCLUSIONS: The presented data suggest that gastritis induced by H. pylori may be associated with recurrent abdominal pain and that in Switzerland infections with H. pylori primarily involve persons who are non-Swiss. A combined therapy results in eradication of the bacterium and in improvement of the clinical symptoms in a significant majority of the patients.

Ontogenetic aspects of the intestinal immune system in man.

The development of the mucosal immune system in the human fetus has been studied in some detail. Aggregates of T and B cells form early Peyer's patches by 16 weeks gestation and by 19 weeks organised Peyer's patches with T and B cell zones are seen. T cells populate the mucosal lamina propria and epithelium from 11 weeks gestation and increase in number thereafter. As in the adult, most intraepithelial lymphocytes are CD8+ and most lamina propria T cells are CD4+. By 20 weeks, villus epithelial cells are HLA-DR+ and secretory component is also expressed. In the absence of lumenal stimulation in the fetus there is no intestinal secretory IgA antibody response. A few IgA plasma cells are present in fetal salivary glands but the number does not dramatically increase until after birth.

Tumour necrosis factor alpha in stool as a marker of intestinal inflammation.

Measurement of disease activity in patients with inflammatory bowel disease is difficult. The best available methods are complex and time consuming, but it may be possible to use tumour necrosis factor alpha (TNF alpha) concentration in stool as a marker of disease activity. We measured TNF alpha concentrations in stool samples from normal children, infants with diarrhoea, and children with inflammatory bowel disease in active and inactive phases of the disease. In 10 normal children and 14 children with diarrhoea, median stool TNF alpha concentrations were 58 and 45 pg/g stool, respectively. Compared with diarrhoeal controls, stool TNF alpha concentrations were significantly increased in children with active Crohn's disease (n = 13, median 994 pg/g, p less than 0.0002) and active ulcerative colitis (n = 4, range 276-5982 pg/g, p less than 0.003). In patients with inactive disease, either as a result of surgery or treatment with steroids, the concentration of stool TNF alpha fell to those of controls. Measurement of stool TNF alpha concentrations may provide a simple way to monitor disease activity in inflammatory bowel disease.

High endothelin-1 immunoreactivity in Crohn's disease and ulcerative colitis.

Both immunological hypersensitivity and vascular abnormalities have been implicated in the pathogenesis of inflammatory bowel disease. In an attempt to link the two hypotheses, we sought evidence of local production of endothelin-1, a potent vasoconstrictor, in patients with Crohn's disease and ulcerative colitis. An immunohistochemical method was used to detect endothelin-1 in tissue samples from sixteen Crohn's disease patients, nine ulcerative colitis patients, and thirteen controls. In the controls, positively staining cells were infrequent in both lamina propria (mean 0.9% of total cells, 95% confidence interval 0.1-1.7%) and submucosa (2.3%, 0.4-4.1%). The percentage of endothelin-immunoreactive cells was significantly higher in the two disease groups than in the controls. Among the Crohn's disease patients, there were more immunoreactive cells in the submucosa than in the lamina propria (19.1%, 15.2-22.1% vs 12.3%, 8.1-16.5%; p less than 0.001), whereas the converse was true for the ulcerative colitis group (8.6%, 1.1-16.1% vs 24.4%, 14.1-34.6%; p less than 0.001). Immunoreactive macrophage aggregates around submucosal blood vessels were common in samples from Crohn's disease patients. Endothelin concentrations, measured by radioimmunoassay, in supernatants of homogenised tissue samples were significantly higher in Crohn's disease and ulcerative colitis than in controls. We suggest that local endothelin production by inflammatory cells may contribute to vasculitis in chronic inflammatory bowel disease by inducing intestinal ischaemia through vasoconstriction.

Location of tumour necrosis factor alpha by immunohistochemistry in chronic inflammatory bowel disease.

This study determined the location and tissue density of cells immunoreactive for tumour necrosis factor alpha (TNF alpha) in intestinal specimens from 24 patients with chronic inflammatory bowel disease (15 with Crohn's disease, nine with ulcerative colitis) and 11 controls. There was significantly increased density of TNF alpha immunoreactive cells in the lamina propria of both ulcerative colitis and Crohn's disease specimens, although the distribution of these cells differed in the two conditions. In ulcerative colitis most of the TNF alpha immunoreactivity was seen in the subepithelial macrophages, with comparatively less in the deep lamina propria, while in Crohn's disease immunoreactive cells were distributed evenly throughout the lamina propria. Increased submucosal immunoreactivity was found only in Crohn's disease, in which TNF alpha positive macrophages tended to cluster around arterioles and venules, often infiltrating and disrupting vascular endothelium. It is suggested that this degree of TNF alpha production probably contributes significantly to the pathogenesis of both Crohn's disease and ulcerative colitis, by impairing the integrity of epithelial and endothelial membranes, increasing inflammatory cell recruitment, and by prothrombotic effects on the vascular endothelium.

Cerebral tuberculosis presenting as complex febrile convulsions.

Complex febrile convulsions were the initial clinical manifestation of miliary tuberculosis in a 4-year-old immigrant girl. The cerebral lesions were visible only after contrast-enhanced cranial computed tomography (CT) while native CT scan as well as cell count and glucose concentration in the cerebrospinal fluid were normal. Mycobacterium tuberculosis was cultured from gastric aspirate and liver biopsy tissue. Treatment with isoniazid and rifampin for 12 months, pyrazinamide for 9 months, and ethambutol for the initial 6 weeks resulted in resolution of the cerebral lesions but a retinal scar after granuloma formation in the right eye caused reduced visus. This case demonstrates the importance of thorough search for tuberculosis even in the absence of overt clinical pulmonary signs especially in high-risk individuals such as immigrants.

Tetrahydrobiopterin in the treatment of infantile hypertrophic pyloric stenosis.

Evidence is emerging that reduced nitric oxide production may be involved in the pathogenesis of hypertrophic pyloric stenosis. Nitric oxide synthase (NOS) requires tetrahydrobiopterin (BH4) for activity. Four infants with hypertrophic pyloric stenosis were treated with oral BH4 (10 mg/kg/day) for 2.5 days. Although plasma total biopterin increased significantly at 3, 27, and 51 h after BH4 administration, there was no effect on the production of plasma cGMP, nitrite, nitrate, or citrulline. Ultrasound investigations before and after the ingestion of BH4 revealed no changes in the hypertrophic pyloric stenosis. We conclude that oral BH4, in the dose utilized in our investigations, does not modify the cause of hypertrophic pyloric stenosis, presumably because it did not restore nitric oxide production in the nonadrenergic noncholinergic nerves of the enteric nervous system.

Interstitial deletion, del(4)(q12q21.1), owing to de novo unbalanced translocation in a 2 year old girl: further evidence that the piebald trait maps to proximal 4q12.

A very short, microcephalic, and mentally retarded 2 year old girl showed minor anomalies including prominent occiput, delayed closure of the anterior fontanelle, high frontal hairline, prominent ears, upward slanting palpebral fissures, a small nose with bulbous tip, delayed tooth eruption and bone maturation, and short and tapering fingers and toes. She did not have a white forelock. Cytogenetic investigation disclosed a de novo unbalanced translocation between chromosomes 4 and 18 with deletion of 4q12-->q21.1. Molecular investigation showed lack of a paternal allele for the microsatellite markers D4S392 and D4S398. This case shows indirect evidence that the piebald gene maps to proximal 4q12.

Familial progressive tubulo-interstitial nephropathy and cholestatic liver disease -- a newly recognized entity?

UNLABELLED: We describe two siblings (female and male) with progressive tubulo-interstitial nephropathy and cholestatic liver disease. The main characteristics were progressive renal failure and elevated liver enzymes (AST, ALT and gamma-GT). Dialysis was started at the age of 1.9 and 6.5 years, respectively. Renal histology disclosed sclerosed glomeruli and atrophic tubules; the interstitium was fibrotic and infiltrated by lymphocytes. Endoscopic retrograde cholangiopancreatography revealed segmental irregularities and narrowing of the intrahepatic bile ducts, consistent with early primary sclerosing cholangitis. Liver histology showed enlarged portal triads, mild proliferation and inflammation of bile ducts, and fibrosis. At 5.9 years the girl underwent a successful renal transplantation whereas the boy is still on dialysis. CONCLUSION: The association of progressive tubulointerstitial nephropathy and cholestatic liver disease, consistent with early primary sclerosing cholangitis, constitutes a distinct autosomal recessive entity.

Persistence of the intestinal defect in abetalipoproteinaemia after liver transplantation.

A 16-year-old girl is described with abetalipoproteinaemia who underwent liver transplantation for hepatic cirrhosis. After this procedure her serum lipoprotein profile was corrected; however, fat malabsorption and steatorrhea persisted because the primary defect, a mutant microsomal triglyceride-transfer protein, remains expressed in the intestine.