Wall teichoic acid structure governs horizontal gene transfer between major bacterial pathogens.

Area of Science:

• Microbiology
• Bacterial genetics
• Evolutionary biology

Background:

• Mobile genetic elements (MGEs) carrying virulence and resistance genes are common in bacterial pathogens.
• The mechanisms enabling MGEs to transfer between different bacterial species remain largely unknown.
• Staphylococcus aureus frequently exchanges MGEs, like S. aureus pathogenicity islands (SaPIs), via helper phages.

Purpose of the Study:

• To investigate the mechanisms of horizontal gene transfer (HGT) across different bacterial species.
• To understand how Staphylococcus aureus ST395, a specific lineage, exchanges MGEs with other species.
• To identify factors that permit HGT across significant phylogenetic distances.

Main Methods:

• Comparative genomic analysis of Staphylococcus aureus ST395 and other bacterial species.
• Investigation of wall teichoic acid (WTA) structures in different bacterial lineages.
• Experimental manipulation of WTA expression in bacteria to assess HGT efficiency.

Main Results:

• The S. aureus ST395 lineage, unlike typical S. aureus, exchanges SaPIs with species like Staphylococcus epidermidis and Listeria monocytogenes.
• ST395 exhibits an unusual WTA structure that resembles that of its HGT partners.
• Ectopic expression of S. aureus WTA in distantly related bacteria enables efficient HGT with typical S. aureus.

Conclusions:

• A 'glycocode' involving WTA structures and specific helper phages facilitates HGT across broad phylogenetic distances.
• This mechanism shapes the evolution of Gram-positive bacterial pathogens.
• Understanding this 'glycocode' is crucial for controlling the spread of virulence and resistance genes.