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Staphylococcus aureus in chronic and recurrent infections
L Slobodníková1, D Kotulová, I Zahradníková
1Institute of Microbiology, Medical Faculty, Comenius University, Slovak Republic.
Abstract:
Ninety-four Staphylococcus aureus strains isolated from chronic and recurrent skin and respiratory tract infections were investigated for several virulence factor expressions. Production of protein A was noticed in all of the tested strains in amounts from less than 0.1 to more than 2.5 ng per 10(6) bacterial cells. The percentage of the extracellularly produced protein A was found to lie between 4.5 and 27.8%. Two strains (both from the respiratory tract) produced more than 50% of protein A in the extracellular form and one strain did not produce any detectable amount of the extracellular protein A; 99% of the tested strains produced the clumping factor, 96% staphylocoagulase, 79% staphylokinase and 90% gelatinolytic activity; 79% produced alpha-toxin exclusively or in combination with delta- or beta-toxin; 8% of strains produced beta-toxin. There were differences in beta-toxin production between strains from the respiratory tract (5%) and skin infections (25%). delta-Toxin was produced by 53% of the strains. In each of the tested strains a complex of virulence factors was detected. The importance of inactivated extracellular products (especially alpha- and delta-toxin and in the case of skin infections also beta-toxin) as components of staphylococcal whole-cell vaccine was suggested.
Insights
This study investigated virulence factors in Staphylococcus aureus from skin and respiratory infections. Most strains produced protein A, clumping factor, staphylocoagulase, and gelatinolytic activity, suggesting their role in vaccines.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Vaccine Development
Background:
- Staphylococcus aureus is a significant pathogen causing chronic and recurrent skin and respiratory tract infections.
- Understanding the expression of virulence factors is crucial for developing effective treatments and vaccines.
- Virulence factors contribute to bacterial survival, colonization, and host tissue damage.
Purpose of the Study:
- To investigate the expression of various virulence factors in Staphylococcus aureus strains isolated from human infections.
- To determine the prevalence of protein A, clumping factor, staphylocoagulase, staphylokinase, gelatinolytic activity, and toxins (alpha, beta, delta) in these strains.
- To explore the potential of inactivated extracellular virulence factors as components of a staphylococcal whole-cell vaccine.
Main Methods:
- Ninety-four Staphylococcus aureus strains were isolated from patients with chronic and recurrent skin and respiratory tract infections.
- Virulence factor expression, including protein A, clumping factor, staphylocoagulase, staphylokinase, gelatinolytic activity, and toxins, was assessed.
- Quantitative and qualitative analyses were performed to determine the presence and amounts of these factors.
Main Results:
- All strains produced protein A, with varying amounts of extracellular protein A.
- High percentages of strains expressed clumping factor (99%), staphylocoagulase (96%), gelatinolytic activity (90%), and staphylokinase (79%).
- Alpha-toxin was produced by 79% of strains, delta-toxin by 53%, and beta-toxin by 8% (with higher prevalence in skin isolates). A complex of virulence factors was detected in all strains.
Conclusions:
- Staphylococcus aureus strains possess a diverse array of virulence factors, often expressed in combination.
- Extracellular virulence factors, particularly alpha-toxin, delta-toxin, and beta-toxin (for skin infections), are potential candidates for inactivated whole-cell vaccines.
- Further research into the immunogenicity and efficacy of these components is warranted for vaccine development.