Identification of Mucosa-Invading and Intravascular Bacteria in Feline Small Intestinal Lymphoma

Area of Science:

• Veterinary Pathology
• Microbiology
• Oncology

Background:

• Persistent gastrointestinal bacterial infections are linked to cancers and lymphomas in humans and animals.
• Feline alimentary lymphoma is a significant concern in veterinary medicine.

Purpose of the Study:

• To investigate the association between mucosa-associated bacteria and alimentary lymphoma in cats.
• To determine the spatial distribution of bacteria in relation to lymphoma subtypes.

Main Methods:

• Intestinal biopsies from 50 cats with alimentary lymphoma and 38 control cats were analyzed.
• Fluorescence in situ hybridization (FISH) with the eubacterial probe EUB-338 was used to identify and localize bacteria.
• Bacterial presence was assessed in various locations: luminal debris, mucus, epithelium, mucosa, blood vessels, and serosa.

Main Results:

• Mucosa-invasive bacteria were significantly more frequent in large cell lymphoma (82%) compared to small cell lymphoma (18%) and controls (3%).
• Intravascular bacteria were exclusively found in large cell lymphoma cases (29%).
• Serosal colonization was more common in large cell lymphoma (57%) than in small cell lymphoma (11%) and controls (6-8%).

Conclusions:

• The high prevalence of invasive bacteria, particularly intravascular and serosal, in cats with large cell lymphoma may contribute to sepsis-related complications.
• These findings suggest a potential role for bacterial invasion in the pathogenesis of feline alimentary lymphoma, especially large cell type.
• Further research is needed to elucidate the precise role of intramucosal bacteria in feline lymphoma development.