Co-culturing with Streptococcus anginosus alters Staphylococcus aureus transcriptome when exposed to tonsillar cells

Area of Science:

• Microbiology and Molecular Biology
• Host-Microbe Interactions
• Bacterial Pathogenesis

Background:

• Understanding Staphylococcus aureus (S. aureus) throat colonization is crucial for managing infections and recurrence.
• The role of co-existing microbes in S. aureus adaptation to the human throat requires further investigation.

Purpose of the Study:

• To identify S. aureus genes critical for colonization in the presence of human tonsillar epithelial cells and Streptococcus anginosus (S. anginosus).
• To compare the transcriptome of S. aureus during co-culture with S. anginosus versus S. aureus grown alone.

Main Methods:

• In vitro co-culture experiments were conducted using S. aureus and S. anginosus with human tonsillar epithelial cells.
• RNA sequencing was employed to identify interaction-induced transcriptional alterations and differentially expressed genes (DEGs).
• Gene enrichment analysis was performed on the identified DEGs.

Main Results:

• A significant number of DEGs (332 at 1h, 279 at 3h) were identified in S. aureus during co-culture.
• The adhesion-related gene serine-aspartate repeat-containing protein D (sdrD) was highly upregulated in S. aureus when co-cultured with S. anginosus.
• Several virulence genes encoding secreted proteins were upregulated in the presence of both S. anginosus and tonsillar cells, with iron not appearing to be a limiting factor.

Conclusions:

• The study identified key S. aureus genes involved in adaptation and colonization within the complex throat environment.
• Findings provide insights into bacterial interactions that may influence S. aureus persistence and infection.
• Identified genes warrant further investigation for developing targeted interventions against S. aureus throat colonization.