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Pathogenesis of the mouse keratitis produced with Pseudomonas aeruginosa
Abstract:
For the purpose of studying the pathogenesis of corneal infection of Pseudomonas aeruginosa, was examined virulence of elastase and protease producing strains or non-producing strains of the bacteria by using the cornea of mouse. The cornea of mouse was experimentally incised, and then P. aeruginosa cultures were dropped once onto it. As a result serious ulcers were caused over the entire cornea, and abscesses in its central area, by 10(5) and 10(7) viable cells of the enzymes producing strains IID 1210 and NO-5 of P. aeruginosa, respectively. Histological destruction, enlargement and cellular infiltration were observed in the corneal epithelium and stroma. On the other hand, P. aeruginosa strains NC-5 and N-10, enzymes non-producing ones, could not cause corneal lesions such as ulcers or abscesses. However, strain PA-103, which is considered to produce neither of the enzymes, could not cause corneal ulcers but cause uveitis even with 10(5) viable cells per mouse. Histologically, concentrated serous exudatation and severe cellular infiltration were noted in the anterior chamber. Necrosis was observed in the entire layer of the cornea. However, the corneal damage caused by strain PA-103 was clearly different from one due to the enzymes producing strains. Additive synergistic effect of protease on the virulent degree of strain NC-5 against the cornea was detected.
Insights
Pseudomonas aeruginosa strains producing elastase and protease cause severe corneal ulcers in mice. Non-producing strains do not cause lesions, highlighting the role of these enzymes in bacterial keratitis.
Area of Science:
- Ophthalmology
- Microbiology
- Pathogenesis
Background:
- Corneal infections by Pseudomonas aeruginosa are a significant cause of vision loss.
- The specific virulence factors contributing to P. aeruginosa keratitis require further elucidation.
Purpose of the Study:
- To investigate the role of elastase and protease production in the pathogenesis of P. aeruginosa corneal infections.
- To compare the virulence of enzyme-producing and non-producing P. aeruginosa strains in a mouse model.
Main Methods:
- Experimental corneal incision in mice followed by topical application of P. aeruginosa strains.
- Assessment of corneal lesions (ulcers, abscesses) and histological examination of corneal tissues.
- Evaluation of uveitis induction by specific bacterial strains.
Main Results:
- Enzyme-producing strains (IID 1210, NO-5) caused severe corneal ulcers and abscesses.
- Non-producing strains (NC-5, N-10) did not induce significant corneal lesions.
- Strain PA-103, considered non-enzymatic, induced uveitis and corneal necrosis, distinct from enzyme-producing strains.
- Protease showed an additive synergistic effect on the virulence of strain NC-5.
Conclusions:
- Elastase and protease production are critical virulence factors for P. aeruginosa-induced corneal ulceration.
- P. aeruginosa can cause keratitis and uveitis through different mechanisms, depending on enzyme production.
- Protease plays a synergistic role in enhancing bacterial virulence against the cornea.