Shaleen Vasavada, MD1, Yinghong Wang, MD, PhD2; 1Baylor College of Medicine, Houston, TX; 2University of Texas MD Anderson Cancer Center, Houston, TX
Introduction: The role of Aeromonas spp. as a gastrointestinal pathogen is debated.1 Here we present an Aeromonas infection in a patient with recurrent immune checkpoint inhibitor (ICI) colitis.
Methods: A 61-year-old Caucasian female with Stage IV Melanoma and history of recurrent ICI colitis presented with 6 days of watery diarrhea, nausea and vomiting. The patient had recently completed 2nd induction of Ipilimumab, an anti-CTLA-4 immunotherapy agent, while being on vedolizumab concurrently with oral budesonide for previous episodes of nausea and vomiting. She endorsed intermittent abdominal cramping and decreased PO tolerance but denied fevers, bloody diarrhea, hematemesis. On exam, abdomen was benign and non-tender. Serology labs were unremarkable. Stool studies were significant for positive lactoferrin and elevated calprotectin to 432 μg/g. Patient was started on solumedrol 40mg IV BID empirically. GI multiplex PCR panel was negative including C. Difficile. Stool culture was positive for pan-susceptible Aeromonas spp. Patient was started on a 7-day course of Ciprofloxacin 500mg BID and prednisone taper resulting in improved PO tolerance, resolution of diarrhea and decreased nausea and vomiting on discharge.
Discussion: Aeromonas spp. infections, although rare, most typically present with gastrointestinal symptoms. It has been implicated as an opportunistic pathogen in inflammatory bowel disease; however, its role in patients with ICI colitis remains unclear.2
Our patient had presented with similar symptoms and negative stool cultures several months prior and was treated for ICI colitis. This diagnosis was confirmed by colonoscopy showing active cryptitis and apoptotic bodies. In the current presentation, it is unclear what the primary cause of her symptoms was. Concurrent administration of both antibiotics and steroids improved her symptoms possibly suggesting a combination of Aeromonas spp. infection and ICI colitis which has never been reported previously in literature. Further studies with larger cohorts of patients with ICI colitis are warranted to investigate the pathogenicity and role of Aeromonas infection.
1. Janda, J. M. & Abbott, S. L. The Genus Aeromonas: Taxonomy, Pathogenicity, and Infection. Clin. Microbiol. Rev. 23, 35–73 (2010). 2. Lobatón, T. et al. Aeromonas Species: An Opportunistic Enteropathogen in Patients with Inflammatory Bowel Diseases? A Single Center Cohort Study. Inflamm. Bowel Dis. 21, 71–78 (2015).
Disclosures: Shaleen Vasavada indicated no relevant financial relationships. Yinghong Wang indicated no relevant financial relationships.