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Open Access Highly Accessed Research article

Comparison of the virulence of exopolysaccharide-producing Prevotella intermedia to exopolysaccharide non-producing periodontopathic organisms

Takeshi Yamanaka1*, Kazuyoshi Yamane1, Tomoyo Furukawa1, Chiho Matsumoto-Mashimo1, Chieko Sugimori1, Takayuki Nambu1, Noboru Obata1, Clay B Walker2, Kai-Poon Leung3 and Hisanori Fukushima1

Author Affiliations

1 Department of Bacteriology, Osaka Dental University, 8-1 Kuzuha-Hanazono, Hirakata, 573-1121 Japan

2 Department of Oral Biology, College of Dentistry, University of Florida, Box 100424 UF Health Science Center, Gainesville, FL 32610-0424, USA

3 US Army Dental and Trauma Research Detachment, Institute of Surgical Research, 3650 Chambers Pass, Fort Sam Houston, TX 78234-6315, USA

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BMC Infectious Diseases 2011, 11:228  doi:10.1186/1471-2334-11-228

Published: 25 August 2011



Evidence in the literature suggests that exopolysaccharides (EPS) produced by bacterial cells are essential for the expression of virulence in these organisms. Secreted EPSs form the framework in which microbial biofilms are built.


This study evaluates the role of EPS in Prevotella intermedia for the expression of virulence. This evaluation was accomplished by comparing EPS-producing P. intermedia strains 17 and OD1-16 with non-producing P. intermedia ATCC 25611 and Porphyromonas gingivalis strains ATCC 33277, 381 and W83 for their ability to induce abscess formation in mice and evade phagocytosis.


EPS-producing P. intermedia strains 17 and OD1-16 induced highly noticeable abscess lesions in mice at 107 colony-forming units (CFU). In comparison, P. intermedia ATCC 25611 and P. gingivalis ATCC 33277, 381 and W83, which all lacked the ability to produce viscous materials, required 100-fold more bacteria (109 CFU) in order to induce detectable abscess lesions in mice. Regarding antiphagocytic activity, P. intermedia strains 17 and OD1-16 were rarely internalized by human polymorphonuclear leukocytes, but other strains were readily engulfed and detected in the phagosomes of these phagocytes.


These results demonstrate that the production of EPS by P. intermedia strains 17 and OD1-16 could contribute to the pathogenicity of this organism by conferring their ability to evade the host's innate defence response.