P504 Prevalence of gastrointestinal infections in ulcerative colitis patients assessed with QIASTAT-DX® GASTROINTESTINAL PANEL 2

Abstract

Abstract Background In inflammatory bowel disease (IBD), an acute clinical flare may be due to either disease exacerbation or an enteric infection. Thus, it is recommended to exclude infections before escalating IBD therapy. In this setting, conventional tests identify only a minimal proportion of infections (i.e. 10%). Whether nucleic acid multiplex tests can expand the range of detected pathogens and increase the overall prevalence is still a matter of debate. Methods We performed a single-center transversal prospective study at Fondazione IRCCS Policlinico Ca’ Granda. Stool samples from consecutive ulcerative colitis (UC) patients experiencing a disease flare and a group of patients in clinical remission were enrolled between February and October 2023 and tested with QIAstat-Dx Gastrointestinal Panel 2 (Qiagen GmbH, Hilden, Germany) for simultaneous qualitative detection and identification of nucleic acids from multiple viruses, bacteria, and parasites. Clinically active disease was defined as a Partial Mayo Score (PMS) of ≥2. Results Overall, 85 UC patients were enrolled. Demographics and clinical features are displayed in Table 1. Median age was 42 (18-79), 52% were males. The two most common treatment regimens were mesalamine (54%) and biologic/small molecule treatment (35%). 66 (78%) patients were clinically active, while 19 (22%) were in remission. In the active group, median bowel movements were 5 (3-15), 58 (88%) patients had loose stool, 32 (49%) reported abdominal pain, 40 (61%) urgency, 10 (15%) overnight symptoms, 6 (9%) fever. Median PMS was 5 (2-8). Median hemoglobin was 13.8 (8.2-16.4) g/dL, fecal calprotectin 508 (<5-4980) ug/g. Prevalence of gastrointestinal infections with QIAstat-Dx was 30 vs. 10% (p=0.13) in active vs. remission group, respectively. The most common infections were: C.Difficile infection (CDI) (4 cases), Cytomegalovirus (CMV) (4 cases) and enteropathogenic E.Coli (EPEC) (4 cases). Regarding viral and E. Coli infections, clinical remission (PMS <2) occurred spontaneously. As for CMV, Campylobacter spp., and CDI, all patients except one achieved remission following specific antimicrobial treatment. In one patient CMV infection led to hospital admission (circulating CMV DNA 35,395 IU/mL). The remaining patient did not receive specific antiviral therapy since sigmoidoscopy only detected isolated CMV+ cells, and remission was achieved with UC treatment escalation. Conclusion In UC patients experiencing a clinical flare, prevalence of gastrointestinal infections with QIAstat-Dx® Gastrointestinal Panel 2 is numerically higher than patients in remission. Further studies are needed to investigate whether increased detection could influence the clinical outcomes of IBD patients and time and costs for the healthcare system.