Endogenous and exogenous glucocorticoids in experimental enterococcal infection

Area of Science:

• Immunology
• Endocrinology
• Microbiology

Background:

• Enterococcus faecalis infections can be severe.
• The role of the host's stress response in these infections is not fully understood.

Purpose of the Study:

• To investigate the protective role of the adrenal-glucocorticoid response during Enterococcus faecalis infection.
• To determine if this response influences tumor necrosis factor alpha (TNF-alpha) production and host survival.

Main Methods:

• Mice were infected with Enterococcus faecalis strains (K9 and CP-1).
• Adrenalectomy and sham surgeries were performed.
• Corticosterone levels, peritoneal TNF-alpha, and survival rates were measured.
• Dexamethasone treatment was administered.

Main Results:

• Adrenalectomized mice showed increased peritoneal TNF-alpha but were more susceptible to lethal E. faecalis CP-1 infection.
• Glucocorticoid treatment (dexamethasone) suppressed TNF-alpha and partially protected against lethal infection.
• E. faecalis K9 infection susceptibility was not significantly altered by adrenalectomy.
• Strain-specific differences in protection were observed.

Conclusions:

• The host's glucocorticoid response to E. faecalis can suppress TNF-alpha production.
• This response offers protection against lethal enterococcal infections, with efficacy varying by bacterial strain.
• The adrenal-glucocorticoid axis plays a critical role in modulating the immune response to E. faecalis.