Related Experiment Videos
[Shigella dysenteriae strains having a provisional serovar isolated from imported diarrheal cases in Tokyo]
S Matsushita1, S Yamada, Y Kudoh
1Department of Microbiology, Tokyo Metropolitan Research Laboratory of Public Health.
Abstract:
Two bacterial strains (ME448 and ME474) isolated from stool cultures of imported cases in Tokyo in 1987 had typical biochemical characteristics of Shigella dysenteriae. The results of antigenic analyses showed that they were serologically identical to each other, but did not belong to any of the established Shigella serovars. These strains were positive for Serény test in guinea pig eye and cell-invasion test in HeLa cells. The strains also had virulence-plasmid encoding outer membrane proteins, indicating that they were pathogenic. We then contacted the Centers for Disease Control in the United States and the Central Public Health Laboratory in the United Kingdom and arranged serological examinations of the strain ME448. From the results, the strain was confirmed to have provisional S. dysenteriae serovar E23507. Although the serovar had been isolated from a Swedish patient who developed diarrhea while in India, this is thought to be the first report of its isolation in Japan.
Insights
Two novel Shigella dysenteriae strains were identified in Japan, exhibiting pathogenic traits and distinct serological profiles. This marks the first reported isolation of the provisional S. dysenteriae serovar E23507 in the country.
Area of Science:
- Microbiology
- Bacteriology
- Infectious Diseases
Background:
- Shigella dysenteriae causes bacillary dysentery, a severe diarrheal disease.
- Accurate identification and serotyping of Shigella strains are crucial for epidemiological surveillance and control.
- Previous reports of S. dysenteriae serovar E23507 were limited to a Swedish patient with travel history to India.
Purpose of the Study:
- To characterize two bacterial strains isolated from imported cases in Tokyo.
- To determine the serological identity and pathogenicity of these novel strains.
- To report the first isolation of Shigella dysenteriae serovar E23507 in Japan.
Main Methods:
- Bacterial isolation from stool cultures.
- Biochemical characterization and antigenic analysis.
- Serény test in guinea pigs and cell-invasion assays in HeLa cells.
- Virulence plasmid analysis.
- International collaboration for serological confirmation.
Main Results:
- Two strains, ME448 and ME474, showed biochemical characteristics of Shigella dysenteriae.
- Strains were serologically identical but did not match established Shigella serovars.
- Both strains were positive in Serény and cell-invasion tests, possessing virulence plasmids.
- Strain ME448 was confirmed as provisional S. dysenteriae serovar E23507.
- This serovar was previously identified in a patient with travel history to India.
Conclusions:
- The isolation of S. dysenteriae serovar E23507 in Japan represents a significant public health finding.
- These pathogenic strains highlight the importance of ongoing surveillance for imported infectious agents.
- Further investigation into the epidemiology and transmission of this serovar in Japan is warranted.