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Pathogenicity of Propionibacterium acnes in mixed infections with facultative bacteria
1Naval Medical Research Institute, Bethesda, MD 20814-5145.
Abstract:
Single and mixed infections with 11 clinical isolates of Propionibacterium acnes and three facultative bacteria (Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae) were studied in a subcutaneous abscess model in mice. Abscesses were induced by pure cultures of six of 11 strains of P. acnes and by the three facultative bacteria. The abscesses produced by each of the six "virulent" P. acnes isolates mixed with S. aureus, E. coli or K. pneumoniae were larger than those induced by the single organisms in 16 of the 18 combinations. There was a significant increase in the numbers of the six P. acnes strains in 13 of the 18 bacterial mixtures and in the numbers of the facultative bacteria in 17 of the 18 combinations. These data illustrate the potential virulence of some P. acnes strains and their synergic capacity with facultative bacteria.
Insights
Certain Propionibacterium acnes (P. acnes) strains show virulence and can enhance abscess formation when mixed with common bacteria like Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae.
Area of Science:
- Microbiology
- Infectious Diseases
- Bacterial Pathogenesis
Background:
- Propionibacterium acnes (P. acnes) is a bacterium implicated in various infections.
- The synergistic potential of P. acnes with other common bacterial pathogens is not fully understood.
Purpose of the Study:
- To investigate the virulence of clinical P. acnes isolates.
- To evaluate the impact of P. acnes in combination with facultative bacteria on abscess formation.
Main Methods:
- A subcutaneous abscess model in mice was utilized.
- Infections were induced using single and mixed cultures of 11 P. acnes strains and three facultative bacteria (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae).
Main Results:
- Abscesses formed by P. acnes combined with facultative bacteria were larger in 16 of 18 combinations compared to single infections.
- Bacterial loads of both P. acnes and facultative bacteria significantly increased in mixed infections.
Conclusions:
- Specific P. acnes strains exhibit significant virulence.
- P. acnes demonstrates a synergistic capacity with facultative bacteria, enhancing infection severity.