Figure 5.

Microbiome virulence induction. Commensal bacteria are able to sense the host microenvironment and other bacterial populations around them. Under basal conditions, the microbiome has a colonizing and/or symbiotic relationship with the host. During critical illness, microorganisms receive signals from both the host and surrounding bacteria that drive them to a virulent phenotype. Newly pathogenic bacteria can then further injure the already compromised host in a maladaptive positive feedback loop.