Invasive Gastric Candidiasis With Concurrent Clostridioides difficile Colitis: A Case Report and Review of the Literature.

Invasive gastric candidiasis is a rare fungal infection of the stomach, often arising in the setting of immunosuppression, critical illness, mucosal barrier disruption, gut microbial alterations, or antibiotic use. Though Candida spp. are normal flora within the gastrointestinal tract, compromised host defenses can contribute to overgrowth and invasion of the fungal species into deeper tissues. We report a case of an 89-year-old man presenting with concurrent upper gastrointestinal bleeding from diffuse gastric ulcers secondary to invasive gastric candidiasis and diarrhea resulting from Clostridioides difficile colitis. The pathophysiology, diagnosis, and management of invasive candidiasis as well as interactions between gastrointestinal candidiasis and Clostridioides difficile infection are discussed. Overall, this case highlights the interplay between antibiotic use, gut barrier translocation, interactions between microorganisms, and worsening infectious disease in an elderly patient. Similarly, it stresses the importance of maintaining a high index of suspicion for fungal infections in patients with large atypical appearing gastric ulcers, even in the absence of overt immunosuppression.