Background: The risk of opportunistic infection in ulcerative colitis (UC) is significantly higher than that in healthy subjects, and has adverse impact on clinical outcome. Aims: To analyze the prevalence of opportunistic intestinal infection in UC patients and explore the risk factors of UC complicated with opportunistic infection. Methods: Clinical data of patients with UC hospitalized in Peking University Third Hospital from January 2012 to December 2020 were collected retrospectively. Information on demography, clinical characteristics, laboratory, endoscopic and pathological findings, as well as the medication histories were recorded; the factors associated with opportunistic intestinal infection were analyzed using univariate and multivariate analyses. Results: A total of 275 UC patients were included, with an opportunistic intestinal infection rate of 26.2%; among which, rates of cytomegalovirus (CMV), Epstein ‑ Barr virus (EBV), fungi, Clostridium difficile, amoeba, and multiple infection were 13.5%, 14.5%, 5.1%, 1.5%, 1.1%, and 9.1%, respectively. Multivariate Logistic analysis demonstrated that severe disease activity (OR=6.517, 95% CI: 1.487‑28.552, P=0.013) and albumin <30 g/L (OR=3.895, 95% CI: 1.590 ‑ 9.544, P=0.003) were independent risk factors for CMV infection. The independent risk factors for EBV infection included severe disease activity (OR=11.260, 95% CI: 2.249‑56.382, P=0.003), albumin <30 g/L (OR=2.548, 95% CI: 1.096‑5.927, P=0.030) and C‑reactive protein (CRP) elevation (OR=1.046, 95% CI: 1.007‑1.086, P=0.019). While for intestinal fungal infection, the risk in patients with chronic relapsing type UC was lower (OR=0.278, 95% CI: 0.087‑0.886, P=0.030). Intestinal multiple infection was mainly composed of viral infection, and the independent risk factors were similar to those of CMV and EBV infection. Conclusions: Most of the opportunistic intestinal infection in UC patients is viral infection. Disease activity, inflammatory response and reduced albumin are risk factors for intestinal viral infection in UC patients, while the risk of fungal infection is only related to clinical subtyping.

The incidence of inflammatory bowel disease (IBD) is increasing year by year, yet lacking specific treatment, which seriously affects patients' health and quality of life. The pathogenesis of IBD has not been fully clarified, the psycho-neuro-endocrine-immune regulation through gut-brain axis may play an important role in the pathogenesis of IBD. Studies have shown that IBD patient has an increased risk of depression. More than 20% of IBD patients have depression, the incidence is about 2-4 times that of general population. Antidepressant therapy has good efficacy in some IBD patients. The possible mechanism includes affecting the gut-brain axis, inhibiting inflammation, improving mood, etc. However, there are few relevant studies, and the value of antidepressant therapy in the treatment of IBD needs to be further confirmed by large-sample randomized controlled studies. This article reviewed the application of antidepressant therapy in IBD.