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[In vitro virulence of wound infecting staphylococcal isolates from severely burned patients]
M Winkler1, G Erbs, F E Müller
1Lehrstuhl für Medizinische Mikrobiologie und Immunologie, Arbeitsgruppe Infektabwehr, Ruhr-Universität Bochum.
Abstract:
The hemolysin and histamine releasing activity of 30 S. aureus strains isolated from third degree burns of heavily burned patients was detected. The culture supernatants (cs) of Staphylococcus aureus isolated during episodes of invasive burn wound infection displayed significantly lower amounts of hemolysin and histamine releasing activity as compared to cs of bacteria isolated when no sign of septicemia was present. In contrast, when washed bacterial cells were analysed, a reversed ratio could be observed. These data clearly indicate that in strains isolated during invasive burn wound infection pathogenicity factors remain attached to the bacterial surface of the staphylococci investigated.
Insights
Staphylococcus aureus strains from severe burn infections showed lower toxin release in culture supernatants. Pathogenicity factors were instead found attached to bacterial cells during invasive burn wound infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Burn Wound Infections
Context:
- Severe burn injuries are susceptible to bacterial infections, particularly by Staphylococcus aureus.
- Understanding the virulence factors of S. aureus is crucial for managing invasive burn wound infections and preventing sepsis.
- Previous studies have focused on secreted toxins, but the role of cell-associated factors in burn infections is less understood.
Purpose:
- To investigate the hemolysin and histamine-releasing activity of S. aureus strains isolated from burn patients.
- To compare the activity of secreted toxins versus cell-associated factors in strains from invasive versus non-invasive infections.
- To determine if pathogenicity factors remain attached to the bacterial surface during invasive burn wound infections.
Summary:
- Thirty S. aureus strains from third-degree burn patients were analyzed for hemolysin and histamine-releasing activity.
- Strains from invasive burn wound infections showed significantly lower activity in culture supernatants compared to non-septicemic isolates.
- Conversely, washed bacterial cells from invasive infections exhibited higher associated activity, indicating surface attachment of virulence factors.
Impact:
- These findings suggest that pathogenicity factors in S. aureus strains causing invasive burn wound infections are primarily cell-surface associated rather than secreted.
- This has implications for the diagnosis and treatment of severe burn infections, potentially requiring strategies that target bacterial surface components.
- Further research into these surface-bound factors could lead to novel therapeutic approaches for combating S. aureus burn wound sepsis.