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Updated: May 11, 2026

Chronic Salmonella Infection Induced Intestinal Fibrosis
Published on: September 22, 2019
Aggravation of inflammatory bowel diseases by oral streptococci
1Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
Objectives:
Streptococcus mutans can aggravate colitis in mice. We evaluated the virulence of colitis using type strains as well as blood isolates of several oral streptococcal species.
Materials And Methods:
We investigated the susceptibility of blood isolates of several oral streptococci to phagocytosis, adhesion to and invasion of hepatic cells and interferon-γ secretion. A mouse model of dextran sodium sulphate-induced colitis was used to evaluate bacterial aggravation of colitis. In addition, interferon-γ antibody was administered to mice with prominent aggravation of colitis.
Results:
In vitro analyses showed that Streptococcus sanguinis ATCC 10556 was a possible virulent strain among type strains of several oral streptococci, and that analysis of blood isolates of S. sanguinis TW289 revealed a potential virulent strain. Intravenous administration of ATCC 10556 and TW289 caused prominent aggravation of dextran sodium sulphate-induced colitis, and histopathological examinations showed that interferon-γ secretion due to infection of hepatic cells caused colitis aggravation. Administration of interferon-γ antibody suppressed TW289-induced colitis.
Conclusion:
These results suggest that some virulent oral streptococcal strains are associated with the aggravation of colitis induced by enhanced secretion of interferon-γ when they invade the bloodstream.
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