Related Experiment Videos
Plasmids and Aeromonas virulence
R L Brown1, K Sanderson, S M Kirov
1Division of Pathology, University of Tasmania, Hobart, Australia.
Abstract:
Most putative virulence determinants of Aeromonas species are chromosomally encoded. However, several recent reports have indicated that some may be carried on or regulated by plasmids. Therefore, we examined the plasmid carriage rate of a total of 140 clinical and environmental Aeromonas isolates. Plasmid carriage was compared with the ability of an isolate to produce toxins and adhere to HEp-2 cells. Overall, plasmid incidence in Aeromonas species was low (23/140, 16%) and independent of the source of the isolate. Plasmids were, however, more common in environmental isolates of A. veronii biovar sobria than in clinical isolates of this species (P < 0.05). We could find no evidence to support the recent literature findings that plasmids may have a role in Aeromonas virulence.
Insights
This study found that plasmids are uncommon in Aeromonas species and do not appear to contribute to virulence. Plasmid carriage was low overall and not linked to toxin production or HEp-2 cell adhesion in these bacterial isolates.
Area of Science:
- Microbiology
- Bacterial Genetics
- Molecular Biology
Background:
- Most Aeromonas virulence factors are chromosomally encoded.
- Recent studies suggest plasmids might play a role in Aeromonas virulence or regulation.
- Understanding plasmid roles is crucial for assessing bacterial pathogenicity.
Purpose of the Study:
- To determine the plasmid carriage rate in clinical and environmental Aeromonas isolates.
- To investigate the correlation between plasmid presence and virulence traits (toxin production, HEp-2 cell adhesion).
- To evaluate the potential role of plasmids in Aeromonas virulence.
Main Methods:
- Screening of 140 clinical and environmental Aeromonas isolates for plasmid DNA.
- Assessing toxin production capabilities of the isolates.
- Evaluating the adherence of isolates to HEp-2 cells.
- Statistical analysis to compare plasmid incidence and virulence traits.
Main Results:
- Overall plasmid incidence was low (16%) and not dependent on the isolate source.
- Plasmids were more frequent in environmental A. veronii biovar sobria than clinical isolates (P < 0.05).
- No evidence linked plasmid carriage to increased toxin production or HEp-2 cell adhesion.
Conclusions:
- Plasmid carriage is infrequent in the studied Aeromonas isolates.
- The findings do not support a significant role for plasmids in Aeromonas virulence.
- Further research may be needed to fully elucidate plasmid functions in specific Aeromonas strains.