Toxigenic Clostridium perfringens isolated from at-risk pediatric inflammatory bowel disease patients.

BACKGROUND AND AIMS: The goal was to identify microbial drivers of IBD, by investigating mucosal-associated bacteria and their detrimental products in IBD patients. METHODS: We directly cultured bacterial communities from mucosal biopsies from pediatric gastrointestinal patients and examined for pathogenicity-associated traits. Upon identifying C. perfringens as toxigenic bacteria present in mucosal biopsies, we isolated strains and further characterized toxicity and prevalence. RESULTS: Mucosal biopsy microbial composition differed from corresponding stool samples. C. perfringens was present in 8 of 9 patients' mucosal biopsies, correlating with hemolytic activity, while not in all corresponding stool samples. Large IBD datasets showed higher C. perfringens prevalence in stool samples of IBD adults (18.7-27.1%) versus healthy (5.1%). In vitro, C. perfringens supernatants were toxic to cell types beneath the intestinal epithelial barrier, including endothelial, neuroblasts, and neutrophils, while impact on epithelial cells was less pronounced, suggesting C. perfringens may be damaging particularly when barrier integrity is compromised. Further characterization using purified toxins and genetic insertion mutants confirmed PFO toxin was sufficient for toxicity. Toxin RNA signatures were found in the original patient biopsies by PCR, suggesting intestinal production. C. perfringens supernatants also induced activation of neuroblast and dorsal root ganglion neurons in vitro, suggesting C. perfringens in inflamed mucosal tissue may directly contribute to abdominal pain, a frequent IBD symptom. CONCLUSIONS: Gastrointestinal carriage of certain toxigenic C. perfringens may have an important pathogenic impact on IBD patients. These findings support routine monitoring of C. perfringens and PFO toxins and potential treatment in patients.

Evaluating the Relationship Between Nutrition and Post-colectomy Pouchitis in Pediatric Patients with Ulcerative Colitis.

BACKGROUND: Pouchitis is the most frequent complication following restorative proctocolectomy and ileal pouch anal anastomosis (RP-IPAA) in patients with Ulcerative colitis (UC). Pediatric data on nutritional status during RP-IPAA and in patients with pouchitis are limited. AIMS: We aimed to delineate nutritional changes in children undergoing 2-stage and 3-stage surgeries and to evaluate the association between nutrition and the development of recurrent or chronic pouchitis. METHODS: This single-center retrospective study involved 46 children with UC who underwent a RP-IPAA. Data were collected at each surgical stage and for up to 2-year post-ileostomy takedown. We used Wilcoxon matched-pairs signed-rank test to evaluate the differences in nutritional markers across surgical stages and logistic regression to identify the factors associated with recurrent or chronic pouchitis. RESULTS: Twenty patients (43.5%) developed recurrent or chronic pouchitis. Children who underwent a 3-stage procedure had improvements in albumin, hematocrit, and body mass index (BMI)-for-age Z-scores (p < 0.01) between the first two stages. A positive trend in BMI-for-age Z-scores (p = 0.08) was identified in children with 2-stage procedures. All patients showed sustained nutritional improvement during the follow-up period. Among patients who underwent 3-stage surgeries, BMI worsened by 0.8 standard deviations (SDs) (p = 0.24) between the initial stages in those who developed recurrent or chronic pouchitis and improved by 1.1 SDs (p = 0.04) in those who did not. CONCLUSIONS: Early improvement in BMI-for-age Z-scores following the initial stage was associated with lower rates of recurrent or chronic pouchitis. Larger prospective studies are needed to validate these findings.

Experience Using Ustekinumab in Pediatric Patients With Medically Refractory Crohn Disease.

INTRODUCTION: Ustekinumab (UST), a human monoclonal antibody against interleukin-12 and 23, is approved to treat adult patients with psoriasis or Crohn disease (CD). Outcomes data for off-label use in pediatric patients with CD are limited. AIM: We conducted a retrospective cohort study to analyze the long-term efficacy of UST, including dose adjustments, in the treatment of pediatric patients with medically refractory CD. Adverse events were documented. METHODS: We identified 40 pediatric patients with CD treated with UST between January 1, 2016 and December 31, 2019. Electronic medical records were reviewed for demographics, Paris Classification, significant comorbidities, previous CD therapy, adverse events after initiation, and surveillance markers at the time of their first dose and most recent clinic visit. A validated abbreviated pediatric CD activity index (aPCDAI) was used to assess response to therapy. RESULTS: Thirty-eight pediatric patients with CD, including 34.2% with stricturing or penetrating disease, were analyzed after initiation of treatment with UST. Median age at diagnosis of CD was 12.5 years, and median age at UST induction was 17.2 years. No patients were anti-TNF-naive, and 34.2% were previously exposed to 2 or more anti-TNF agents. At time of last follow-up, 84.2% of patients remained on UST for a median duration on UST of 62.1 weeks, and 60.5% achieved clinical remission. Patients had significant improvement in aPCDAI scores, clinical remission rates, albumin, and hematocrit, and 89.5% of patients had no significant adverse events. Similar results were observed among those who required dose adjustment, including 61.1% achieving clinical remission, and among those with perianal disease, including 38.5% achieving clinical remission. CONCLUSIONS: Our data suggest that, within our cohort of pediatric patients with CD, UST has long-term efficacy with no observed safety concerns. Dose adjustment may be helpful in achieving clinical remission.

Enteric Virome and Bacterial Microbiota in Children With Ulcerative Colitis and Crohn Disease.

OBJECTIVES: We examined the fecal virome and bacterial community composition of children with Crohn disease (CD), ulcerative colitis (UC), and healthy controls to test the hypothesis that unique patterns of viral organisms and/or presence of bacterial pathogens may be identified that could contribute to the pathogenesis of pediatric inflammatory bowel disease (IBD). METHODS: Fecal samples from 24 children (mean 12.2 years) with CD (n = 7) or UC (n = 5) and similar aged controls (n = 12) were processed to determine individual viromes. Viral sequences were identified through translated protein sequence similarity search. Bacterial microbiota were determined by sequencing of the V4 region of the 16S rRNA gene. RESULTS: Only a few human viruses were detected, so virome analyses focused on bacterial viruses. The relative abundance of Caudovirales was greater than that of Microviridae phages in both IBD and healthy controls. Caudovirales phages were more abundant in CD (mean 80.8%) than UC (48.8%) (P = 0.05) but not controls. The richness of viral strains in Microviridae but not Caudovirales was higher in controls than CD (P = 0.05) but not UC cases. No other measure of phage abundance, richness, or Shannon diversity showed significant difference between the 2 IBD and control groups. Bacterial microbiota analysis revealed that IBD diagnosis, albumin, hemoglobin, erythrocyte sedimentation rate, and probiotic supplementation correlated to the composition of gut bacterial microbiota. CONCLUSIONS: Minor patterns in gut virome and bacterial community composition distinguish pediatric IBD patients from healthy controls. Probiotics are associated with bacterial microbiota composition. These exploratory results need confirmation in larger studies.