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Staphylococcal footpad infection in mice
Abstract:
Local footpad infection in mouse was investigated with 55 clinically isolated strains of Staphylococcus aureus. When 10(7) viable cells were inoculated into the footpad, local swelling and bacterial growth resulted after 24 hr. With a dose of 10(6) cells, moderate swelling was observed after a few hours but the reaction had almost disappeared after 24 hr. About 75% of the staphylococcal strains tested caused footpad edema in mice at doses of 10(7) cells. A statistical comparison of the virulence of the organisms on intravenous and intraperitoneal injection with that in inducing footpad swelling is also reported.
Insights
This study shows that Staphylococcus aureus footpad infections in mice cause swelling and bacterial growth. Higher bacterial doses (10^7 cells) led to significant edema, indicating virulence.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Staphylococcus aureus is a common pathogen causing various infections.
- Understanding the virulence factors of S. aureus is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the local footpad infection model in mice using clinically isolated Staphylococcus aureus strains.
- To evaluate the dose-dependent response and edema-inducing potential of S. aureus.
Main Methods:
- Inoculation of mice footpads with varying doses (10^6 and 10^7 cells) of 55 S. aureus strains.
- Observation and measurement of local swelling and bacterial growth over 24 hours.
- Statistical comparison of footpad swelling with other infection routes (intravenous, intraperitoneal).
Main Results:
- A dose of 10^7 S. aureus cells caused local swelling and bacterial growth within 24 hours.
- A dose of 10^6 cells induced transient swelling.
- Approximately 75% of tested S. aureus strains induced footpad edema at a dose of 10^7 cells.
Conclusions:
- The mouse footpad model is a viable method for assessing S. aureus virulence.
- S. aureus strains exhibit varying degrees of virulence in inducing local footpad edema.
- Dose is a critical factor in the development of S. aureus-induced footpad infections.