Summary: Background  The use of exclusive enteral nutrition to treat paediatric Crohn’s disease (CD) is widely accepted, although the precise mechanism(s) of action remains speculative.Aim  To investigate the changes to key intestinal bacterial groups of Eubacteria, Bacteroides, Clostridium coccoides, Clostridium leptum and Bifidobacteria, during and after exclusive enteral nutrition treatment for CD in paediatric patients and correlate these changes to disease activity and intestinal inflammation.Methods  Stool was collected from six children at diagnosis of CD, during exclusive enteral nutrition and 4 months post‐therapy, and from seven healthy control children. The diversity of bacteria was assessed by polymerase chain reaction‐denaturing gradient gel electrophoresis with changes to bacterial diversity measured by Bray–Curtis similarity, intestinal inflammation assessed by faecal S100A12 and the disease activity assessed by PCDAI.Results  A significantly greater change in intestinal bacterial composition was seen with exclusive enteral nutrition treatment compared with controls. Further, the intestinal bacteria remained altered 4 months following exclusive enteral nutrition completion. Changes in the composition of Bacteroides were associated with reduced disease activity and inflammation.Conclusions  Exclusive enteral nutrition reduces bacterial diversity and initiates a sustained modulation of all predominant intestinal bacterial groups. Exclusive enteral nutrition may reduce inflammation through modulating intestinal Bacteroides species. The implications of these results for exclusive enteral nutrition therapy and CD pathogenesis should now be the subject of further investigation.

Historically, Campylobacteriosis has been considered to be zoonotic; the Campylobacter species that cause human acute intestinal disease such as Campylobacter jejuni and Campylobacter coli originate from animals. Over the past decade, studies on human hosted Campylobacter species strongly suggest that Campylobacter concisus plays a role in the development of inflammatory bowel disease (IBD). C. concisus primarily colonizes the human oral cavity and some strains can be translocated to the intestinal tract. Genome analysis of C. concisus strains isolated from saliva samples has identified a bacterial marker that is associated with active Crohn's disease (one major form of IBD). In addition to C. concisus, humans are also colonized by a number of other Campylobacter species, most of which are in the oral cavity. Here we review the most recent advancements on C. concisus and other human hosted Campylobacter species including their clinical relevance, transmission, virulence factors, disease associated genes, interactions with the human immune system and pathogenic mechanisms.

The presence of Campylobacter species other than Campylobacter jejuni and antibodies to Campylobacter concisus in children were investigated. A significantly greater presence of C. concisus and higher levels of antibodies to C. concisus were detected in children with Crohn's disease (CD) than in controls. Campylobacter species other than C. jejuni were isolated from intestinal biopsy specimens of children with CD.

Campylobacteriosis is a gastroenteritis caused by pathogenicCampylobacterspecies and an important topic in public health. Here we review the global epidemiology of campylobacteriosis in the last eight years between 2014-2021, providing comprehensive and updated information on the reported incidence and outbreaks ofCampylobacterinfections. The government public health website of each of the 195 countries and publications from 2014 to September 2022 in public databases were searched. The reported incidence of campylobacteriosis in pre-COVID-19 years was compared to that during the COVID-19 pandemic in countries where data were available. Czech Republic had the highest reported incidence of campylobacteriosis worldwide (215 per 100,000 in 2019), followed by Australia (146.8 per 100,000 in 2016) and New Zealand (126.1 per 100,000 in 2019).Campylobacterwas one of the most common human enteric pathogens in both developed and developing countries. About 90% of cases of campylobacteriosis were caused byCampylobacter jejuni, whereas less than 10% of cases were caused byCampylobacter coli. OtherCampylobacterspecies were also isolated. The reported incidence and case numbers of campylobacteriosis in developed nations have remained steadily high prior to the COVID-19 pandemic, whilst some countries reported an increasing trend such as France and Japan. While outbreaks were more frequently reported in some countries,Campylobacterinfections were mainly sporadic cases in most of the developed countries.Campylobacterinfection was more common in summer in some but not all countries.Campylobacterinfection was more common in males than females. The COVID-19 pandemic has reduced the reported incidence of campylobacteriosis in most countries where 2020 epidemiology data were available. In conclusion,Campylobacterinfection remains a global health concern. Increased research and improved strategies are needed for prevention and reduction ofCampylobacterinfection.

Crohn's disease (CD) and ulcerative colitis (UC) are the two major forms of inflammatory bowel disease (IBD). A high prevalence of Campylobacter concisus was previously detected in paediatric CD and adult UC. Currently, the prevalence of C. concisus in adult CD and the preferential colonization sites of Campylobacter species in the human intestine are unknown. In this study, we examined the prevalence of Campylobacter species in biopsies collected from multiple anatomic sites of adult patients with IBD and controls. Three hundred and one biopsies collected from ileum, caecum, descending colon and rectum of 28 patients IBD (15 CD and 13 UC) and 33 controls were studied. Biopsies were used for DNA extraction and detection of Campylobacter species by PCR-sequencing and Campylobacter cultivation. A significantly higher prevalence of C. concisus in colonic biopsies of patients with CD (53%) was detected as compared with the controls (18%). Campylobacter genus-PCR positivity and C. concisus positivity in patients with UC were 85% and 77% respectively, being significantly higher than that in the controls (48% and 36%). C. concisus was more often detected in descending colonic and rectal biopsies from patients with IBD in comparison to the controls. C. concisus was isolated from patients with IBD. The high intestinal prevalence of C. concisus in patients with IBD, particularly in the proximal large intestine, suggests that future studies are needed to investigate the possible involvement of C. concisus in a subgroup of human IBD. To our knowledge, this is the first report of the association between adult CD and C. concisus as well as the first study of the preferential colonization sites of C. concisus in the human intestine.