Risk factors and clinical implication of superimposed Campylobacter jejuni infection in patients with underlying ulcerative colitis

BACKGROUND AND AIMS Superimposed Campylobacter jejuni infection (CJI) has been described in patients with ulcerative colitis (UC). Its risk factors and impact on the disease course of UC are not known. Our aims were to evaluate the risk factors for CJI in UC patients and the impact of the bacterial infection on outcomes of UC. METHODS Out of a total of 918 UC patients tested, 21 (2.3%) of patients were found to be positive for CJI (the study group). The control group comprised 84 age-matched UC patients who had tested negative for CJI. Risk factors for CJI and UC-related outcomes at 1 year after diagnosis of CJI were compared between the two groups. RESULTS Ten patients (47.6%) with CJI required hospital admission at the time of diagnosis, including eight for the management of "UC flare". Treatment with antibiotics resulted in improvement in symptoms in 13 patients (61.9%). On multivariate analysis, hospital admission in the preceding year was found to be an independent risk factor for CJI [odds ratio (OR): 3.9; 95% confidence interval (CI): 1.1-14.1] and there was a trend for chronic liver disease as a strong risk factor (OR: 5.0; 95% CI: 0.9-28.3). At 1-year follow up, there was a trend for higher rates of UC-related colectomy (28.8% vs. 14.3%; P = 0.11), and mortality (9.5% vs. 1.2%; P = 0.096) in the study group. CONCLUSION Recent hospitalization within 1 year was found to be associated with increased risk for CJI in UC patients. There was a trend for worse clinical outcomes of UC with in patients with superimposed CJI, which was frequently associated with UC flare requiring hospital admission.