Commensal bacteria augment Staphylococcus aureus infection by inactivation of phagocyte-derived reactive oxygen...

Area of Science:

• Microbiology
• Immunology
• Pathogenesis

Background:

• Staphylococcus aureus is a significant human pathogen.
• Its pathogenicity can be increased by co-infecting microorganisms (augmentation).
• The mechanism of augmentation, particularly macrophage interaction, remains unclear.

Purpose of the Study:

• To investigate the breadth of microorganisms capable of augmenting S. aureus.
• To elucidate the mechanism by which augmentation enhances S. aureus pathogenicity.
• To explore the potential of augmentation as a vaccine model.

Main Methods:

• Testing various cross-kingdom microorganisms for augmentation of S. aureus.
• In vitro assessment of bacterial survival against reactive oxygen species (ROS).
• In vivo studies using ROS-susceptible S. aureus mutants (katA ahpC).
• Cellular studies examining bacterial survival within macrophages.

Main Results:

• Diverse microorganisms, including Enterococcus faecalis, can augment S. aureus virulence.
• Augmentation protects S. aureus from ROS in vitro.
• Augmentation restores virulence to ROS-susceptible mutants in vivo.
• Augmentation enhances bacterial survival within macrophages by mitigating ROS, promoting proliferation and escape.

Conclusions:

• Augmentation is a conserved phenomenon mediated by cross-kingdom microbial interactions.
• The mechanism involves protecting bacteria from host ROS, facilitating intracellular survival and proliferation.
• Augmentation represents a critical factor in initiating infection and offers a novel vaccine strategy.