Thesis
Development of two animal models to study the function of Vibrio parahaemolyticus type III secretion systems
Washington State University
Master of Science (MS), Washington State University
2010
Handle:
https://hdl.handle.net/2376/101363
Abstract
V. parahaemolyticus is an emerging food- and water-borne pathogen that encodes two type III secretions systems (T3SS). In vitro studies link T3SS1 to cytotoxicity while an ileal-loop model indicates that T3SS2 contributes to intestinal fluid accumulation in rabbits. In this study we evaluated the role of the T3SSs during infection using two novel animal models; an orogastric inoculated new-borne piglet model, and an intrapulmonary inoculated mouse model. The strains employed in this study had equivalent growth rates and beta-hemolytic activity based on in vitro assays. Inoculation of 48 h old piglets with 1011 colony forming units (CFU) of the wild-type (NY-4) or T3SS1 deletion-mutant strains resulted in acute, self-limiting diarrhea whereas inoculation with a T3SS2 deletion-mutant strain failed to produce any clinical symptoms. Intrapulmonary inoculation of mice with the wild-type and T3SS2 deletion-mutant strains (5×105 CFU) induced mortality or a moribund state within 12 h (80-100% mortality), whereas inoculation with a T3SS1 deletion-mutant or a T3SS1-T3SS2 double-deletion mutant produced no mortality. Bacteria were recovered from multiple organs regardless of the strain used in the mouse model, indicating that the mice were capable of clearing the lung infection in the absence of a functional T3SS1. Because all strains had a similar beta-hemolysin phenotype, we surmise that thermostable direct hemolysin (TDH) plays a limited role in these models. The two models introduced herein produce robust results and provide a means to determine how different T3SS1 and T3SS2 effector proteins contribute to pathogenesis of V. parahaemolyticus infection.
Metrics
Details
- Title
- Development of two animal models to study the function of Vibrio parahaemolyticus type III secretion systems
- Creators
- Pablo E. Piñeyro. Piñeiro
- Contributors
- Douglas R. Call (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Veterinary Medicine, College of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900524879301842
- Language
- English
- Resource Type
- Thesis