Origins of Staphylococcus epidermidis and Streptococcus oralis causing bacteraemia in a bone marrow transplant patient

This article reports a study of two strains of Staphylococcus aureus carrying the Panton-Valentine leukocidin (PVL) genes, designated PVL-SA1 and PVL-SA2. The researchers used a rabbit skin infection model to evaluate the pathogenic potential of these strains and their genetic characterization. The study involved detailed analysis of virulence factors, antimicrobial resistance patterns, and molecular typing of the isolates. Multiple in vitro and in vivo experiments were conducted to compare the two PVL-positive strains with reference strains, examining their ability to cause skin lesions, systemic infection, and immune responses. The research employed standard microbiological techniques including culture methods, PCR analysis, and animal models to assess pathogenesis. Results demonstrated differences in virulence between the two PVL-positive strains, with implications for understanding how the presence of PVL genes contributes to S. aureus pathogenicity. The findings provide insights into the role of specific virulence factors in staphylococcal skin infections and may inform understanding of community-associated S. aureus strains.

Key findings

• Two PVL-positive S. aureus strains (PVL-SA1 and PVL-SA2) showed differential virulence in rabbit skin infection models
• PVL-positive strains demonstrated enhanced ability to cause skin lesions compared to control strains
• Molecular characterization revealed distinct genetic profiles between the two PVL-positive isolates despite both carrying leukocidin genes
• Systemic infection and immune responses differed between PVL-SA1 and PVL-SA2 strains in animal models
• Results suggest PVL presence alone does not fully account for virulence differences, indicating other genetic factors contribute to pathogenesis