In the adherent mucus compartments, how did Bacteroides spp. differ between small cell GI lymphoma cats and cats with IBD?

• A. Increased in colon adherent mucus
• B. Decreased in ileal adherent mucus
• C. Increased in ileal adherent mucus
• D. No difference in ileal adherent mucus

Answer: (C)

This question is about how disease state reshapes the microbiota that lives attached to the intestinal mucus, and why the pattern differs between small cell GI lymphoma and inflammatory bowel disease in cats, specifically in the ileum. Bacteroides spp. are adept at associating with mucus and metabolizing mucin components, so the ileal adherent mucus becomes a distinct niche whose microbial composition can reflect local pathology.

In cats with small cell GI lymphoma, the ileum is often involved and the tumoral/immune environment disrupts the mucus layer in a way that favors adhesion and growth of Bacteroides in the adherent mucus. That creates an increased presence of Bacteroides in the ileal adherent mucus compared with cats with IBD, where this specific enrichment is not seen to the same extent. Therefore, the ileal adherent mucus shows an increased abundance of Bacteroides in lymphoma relative to IBD.

The other options don’t fit because the finding is about a rise in the ileal mucosal compartment, not a rise in colon adherent mucus, not a decrease in ileal adherent mucus, and not a lack of difference in the ileal mucus niche.