Merit Kase, M.D. [1], Krista Vitikainen, M.D. [1], Clas-Göran af Björkesten, M.D., Ph.D. [1], Veli-Jukka Anttila, M.D., Ph.D. [2], Leo Meriranta M.D. [3], Perttu Arkkila, M.D., Ph.D. [1], Pauliina Molander, M.D., Ph.D. [1]

Affiliates

1 Abdominal Center, Gastroenterology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.2 Department of Infectious Diseases, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.3 Department of Oncology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.

Abstract

Introduction: Enteric pathogens are a leading cause of diarrhea worldwide, even in high-income countries [1]. Moreover, patients
with inflammatory bowel disease (IBD) are at an increased risk of infection [2,3] and gastrointestinal (GI) bacterial infections are
commonly implicated as precipitants of IBD flares [4]. The diagnostic work-up therefore requires consideration of a wide variety of
inflammatory or infectious diseases that mimic IBD.

Aims & Methods: Firstly, we aimed to evaluate in IBD patients factors that predispose to GI, secondly, factors that affect the
severity of the GI infections and lead to hospitalization, and thirdly, how GI bacterial infections alter the activity of IBD further on.
This retrospective, observational, single-center, cohort study comprises 123 patients with ulcerative colitis (UC) or Crohn´s disease
(CD) with confirmed Campylobacter spp., Yersinia spp., Salmonella spp. or enterohemorrhagic E. coli (EHEC) infection, and their age and sex matched controls with IBD but without bacterial GI infection. We identified IBD patients with positive stool samples by
performing a search combining the positive stool sample registry of the Hospital district of Helsinki and Uusimaa and the IBD registry
of Helsinki University Hospital. Patient data from 1 January 2008 to 30 June 2023 was collected retrospectively from patient electronic charts.

Background factors, such as age, sex, IBD type and phenotype, previous surgical treatment, ongoing medication, previous IBD
clinical activity, other comorbidities (based on Charlson Comorbidity Index [CCI]), smoking status, previous long-distance travelling,
infectious symptoms, and need of medical consultations due to GI bacterial infection were evaluated. Follow-up data one to six
months after the GI infection was analyzed. The results of the GI infection patients were compared with the controls.

Results: Out of 5194 IBD patients in the IBD registry, 123 patients were confirmed with Campylobacter spp., Yersinia spp.,
Salmonella spp. or EHEC infection. Of those with a GI bacterial infection, 64% (n=79) had UC and 36% (n=44) had CD. Patients with a GI bacterial infection diagnosis were more likely to have a flare and medication intensification in one to six months after the infection compared to the control group (37% vs 11%, p<0.001, and 37% vs 20%, p=0.006, respectively). Neither age, IBD phenotype, disease activity, CCI, IBD medication nor previous long-distance travelling to a lower hygiene country increased the risk of severe bacterial infection or the need hospital care.

Conclusion: IBD patients having GI bacterial infections are at a higher risk of experiencing an IBD flare and requiring an
intensification in their IBD medication within one to six months after the infection. However, there is no significant association
between different IBD medications or previous symptomatic IBD and the risk for hospitalization.

References:
1. Siciliano V, Nista EC, Rosà T, Brigida M, Franceschi F: Clinical Management of Infectious Diarrhea. Rev Recent
Clin Trials 2020, 15(4):298-308.
2. Rahier JF, Magro F, Abreu C, Armuzzi A, Ben-Horin S, Chowers Y, Cottone M, de Ridder L, Doherty G, Ehehalt Ret al: Second
European evidence-based consensus on the prevention, diagnosis and management of opportunistic infections in
inflammatory bowel disease. J Crohns Colitis 2014, 8(6):443-468.
3. Kirchgesner J, Lemaitre M, Carrat F, Zureik M, Carbonnel F, Dray-Spira R:R isk of Serious and Opportunistic Infections
Associated With Treatment of Inflammatory Bowel Diseases. Gastroenterology 2018, 155(2):337-346 e310.
4. Gecse KB, Vermeire S: Differential diagnosis of inflammatory bowel disease: imitations and complications. Lancet
Gastroenterol Hepatol 2018, 3(9):644-653.

Poster_P3_Pauliina Molander