A mouse model for studying gastrointestinal microbial ecology

The mammalian gastrointestinal (GI) tract harbors a complex microbial ecosystem with hundreds of bacterial species at total levels as high as 10¹¹⁻¹² cells/g tissue. These bacteria play an important role in the health of the host as well as in causing disease, but studies on the roles of the GI microflora are hindered by the lack of a suitable model system. This thesis characterizes and uses a defined flora mouse model to study interactions between exogenous bacteria and the GI microflora. The first part of the thesis characterizes a defined flora mouse model consisting of immunodeficient C.B-17 SCID mice colonized with the eight bacterial strains of the altered Schaedler flora (ASF). Specific and sensitive molecular methods were developed to accurately estimate the levels of different ASF strains. Distribution of specific ASF strains along the GI tract was dependent on the oxygen tolerance of the strains. Fecal levels of different strains, which are typically used as a model for colonic bacteria, were different from colonic levels, although all colonic strains were present in feces. ASF strains were persistent in the mouse GI tract even in the face of long-term exposure to other bacteria. The second part of the thesis evaluates the presence of different ASF strains in inbred and outbred mouse models from different vendors to establish the potential for widespread use of these strains as representatives of the mouse GI microflora. Seven of the eight strains were persistent in both inbred and outbred mice from all vendors studied. This indicates the potential for the ASF strains to be used as a model system even in mouse models that do not harbor a defined flora.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Civil and Environmental Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Sarma-Rupavtarm, Ramahi Bhushan, 1977-

Advisor dc:contributor.advisor

• Martin F. Polz.

• Civil and Environmental Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/31133

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/31133