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[Use of the keratoconjunctival test for determining the virulence of the causative agent of pseudotuberculosis]
Abstract:
When tested in guinea pigs, Y. pseudotuberculosis strains, serovar I (25 strains) and serovar V (1 strain), were found for the first time to be capable of causing keratoconjunctivitis in the animals; the most virulent of these strains caused progressive conjunctivitis and keratitis with generalized infection. The minimum infective dose was 10(4) for conjunctivitis and 10(6) for keratitis. The studied Y. pseudotuberculosis strains, serovars O3 and O9, were found to be incapable of causing conjunctivitis and keratitis. The authors believe that the keratoconjunctival test allows one to evaluate the invasiveness and toxicity of Y. pseudotuberculosis according to the degree of the manifestation and the time of the development of conjunctivitis and keratitis.
Insights
Certain Yersinia pseudotuberculosis strains, serovar I and V, can cause keratoconjunctivitis in guinea pigs. This finding introduces a new test to evaluate bacterial invasiveness and toxicity.
Area of Science:
- Veterinary Ophthalmology
- Microbiology
- Infectious Diseases
Background:
- Yersinia pseudotuberculosis is a bacterial pathogen.
- Previous research has not established its ability to cause eye infections.
Purpose of the Study:
- To investigate the potential of Yersinia pseudotuberculosis strains to cause keratoconjunctivitis in guinea pigs.
- To determine the minimum infective dose for ocular infections.
- To assess the utility of the keratoconjunctival test for evaluating bacterial virulence.
Main Methods:
- Guinea pigs were inoculated with Yersinia pseudotuberculosis strains of serovar I and V.
- Inoculated animals were monitored for the development of conjunctivitis and keratitis.
- Infective doses for ocular and systemic infections were determined.
Main Results:
- Yersinia pseudotuberculosis serovar I (25 strains) and serovar V (1 strain) induced keratoconjunctivitis in guinea pigs.
- The most virulent strains caused progressive conjunctivitis, keratitis, and generalized infection.
- Minimum infective doses were 10^4 for conjunctivitis and 10^6 for keratitis.
- Serovars O3 and O9 strains did not cause ocular disease.
Conclusions:
- Yersinia pseudotuberculosis serovars I and V are capable of causing keratoconjunctivitis in guinea pigs.
- The keratoconjunctival test can serve as a model to assess the invasiveness and toxicity of Yersinia pseudotuberculosis.