Which two bacteria were significantly elevated in cats with small cell lymphoma compared with those with inflammatory bowel disease?

• A. Lactobacillus and Streptococcus
• B. Escherichia coli and Clostridium
• C. Fusobacterium and Bacteroides
• D. Bifidobacterium and Enterococcus

Answer: (C)

In cats with small cell lymphoma, the gut microbial community shifts toward an inflammatory and tumor-associated pattern. Fusobacterium and Bacteroides are two anaerobic groups that tend to flourish in inflamed or structurally altered mucosa, and they’re often enriched when neoplastic processes in the gut change the local environment. Fusobacterium can adhere to and interact with mucosal tissues, sometimes promoting inflammatory signaling, while Bacteroides are versatile mucosa-associated bacteria that can degrade protective layers like mucin and exploit available nutrients in a diseased gut. This combination creates a distinct dysbiosis signature compared with inflammatory bowel disease, where the shifts in microbial communities tend to involve other taxa. The other options describe bacteria that are more typical of general commensal or non-specific shifts and don’t align as closely with the specific pattern linked to small cell lymphoma in these cats.