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Plasmids of human strains of Yersinia enterocolitica: molecular relatedness and possible importance for pathogenesis
Abstract:
One-hundred fifteen strain of Yersinia enterocolitica were examined for plasmids and plasmid-mediated pathogenic properties. Human strains of serotypes O:3 and O:9 harbored plasmids of 46 and 44 megadaltons, respectively, with 90% homology of DNA sequences. The plasmid-mediated properties were calcium dependence, survival in human serum, conjunctivitis provocation in guinea pigs, and O agglutinogens. One strains of serotype O:8 harbored a 42-megadalton plasmid with 75% sequence homology with plasmids of serotypes O:3 and O:9. An additional plasmid-mediated property was lethality for white mice. Filter hybridization of restriction endonuclease-digested plasmid DNA indicated that a 5.6-megadalton fragment of the plasmid of serotype O:8 had virtually no sequence homology with plasmid DNA of serotypes O:3 and O:9 and therefore may be associated with the lethal factor for mice.
Insights
This study investigated Yersinia enterocolitica plasmids and their role in pathogenicity. Key plasmid-mediated traits like serum survival and mouse lethality were identified, with specific DNA fragments linked to virulence.
Area of Science:
- Microbiology
- Molecular Biology
- Pathogen Research
Background:
- Yersinia enterocolitica is a significant foodborne pathogen.
- Plasmids are known to confer virulence factors in bacteria.
- Understanding plasmid-mediated properties is crucial for controlling infections.
Purpose of the Study:
- To identify and characterize plasmids in Yersinia enterocolitica strains.
- To investigate the association between specific plasmids and pathogenic properties.
- To determine the genetic basis of virulence factors, including mouse lethality.
Main Methods:
- Isolation and characterization of plasmids from 115 Yersinia enterocolitica strains.
- DNA sequence homology analysis using filter hybridization.
- Assessment of plasmid-mediated properties: calcium dependence, serum survival, conjunctivitis provocation, O agglutinogens, and mouse lethality.
Main Results:
- Serotypes O:3 and O:9 strains harbored 46 and 44 Mdal plasmids with 90% DNA homology, mediating calcium dependence, serum survival, conjunctivitis, and O agglutinogens.
- Serotype O:8 strain possessed a 42 Mdal plasmid with 75% homology, conferring mouse lethality.
- A 5.6 Mdal fragment of the O:8 plasmid showed no homology to O:3 and O:9 plasmids, potentially linked to lethality.
Conclusions:
- Plasmids play a critical role in Yersinia enterocolitica virulence.
- Specific plasmid DNA sequences are associated with distinct pathogenic traits.
- The O:8 plasmid contains a unique fragment potentially responsible for mouse lethality, offering targets for further research.