The role of gastrointestinal PCR in inflammatory bowel disease flares: A double-edged sword or a diagnostic...

Inflammatory bowel disease (IBD), encompassing Crohn's disease (CD) and ulcerative colitis (UC), is characterized by chronic gastrointestinal inflammation, leading to unpredictable flares and substantial morbidity. Gastrointestinal polymerase chain reaction (GI-PCR) testing has emerged as a widely used diagnostic tool to identify enteric pathogens during IBD exacerbations. It is a novel, quick and sensitive diagnostic test to detect Clostridioides difficile infection (CDI), as well as other enteric pathogens. However, the clinical significance of non-C. difficile pathogens detected by GI-PCR remains uncertain, raising concerns about the over-interpretation of positive results and the potential for unnecessary antimicrobial therapy. While traditional stool culture and microscopy offered limited sensitivity, GI-PCR has dramatically improved pathogen detection rates, identifying infections in up to 26% of IBD patients compared to 5% with conventional methods. Beyond C. difficile, pathogens such as Escherichia coli (especially adherent-invasive strains), Campylobacter, Salmonella, Norovirus and Yersinia enterocolitica are frequently detected in IBD flares. However, whether these microbes actively drive disease exacerbations or merely reflect inflammation-associated dysbiosis remains unclear. Enterobacteriaceae, in particular, bloom in inflamed intestines, raising critical questions regarding their pathogenic role vs. colonization. The high sensitivity of GI-PCR further complicates clinical decision-making, as distinguishing active infection from harmless microbial presence is challenging. This review explores the current literature on GI-PCR in IBD, emphasizing its benefits and limitations. While GI-PCR provides rapid, comprehensive pathogen detection, its indiscriminate application may lead to unnecessary antibiotic use and therapeutic missteps. Understanding the ecological shifts in IBD-associated dysbiosis and refining clinical interpretation of GI-PCR results are essential to optimizing patient management. Future research should aim to delineate the pathogenic significance of non-C. difficile microbes and establish evidence-based protocols for the appropriate use of GI-PCR in IBD care.