The complex interplay between stress and bacterial infections in animals

Area of Science:

• Microbiology
• Immunology
• Neuroendocrinology

Background:

• Neuroendocrine hormones, including glucocorticoids and catecholamines, are released during host stress responses.
• The impact of stress on infections was historically attributed solely to host immune and intestinal barrier functions.
• Chronic stress can shift immune responses from T helper 1 to T helper 2 mediated immunity.

Purpose of the Study:

• To provide an overview of how stress influences the outcome of bacterial infections in animals.
• To highlight the direct effects of stress-related host signals on bacterial pathogens.
• To explore the role of quorum sensing in mediating bacterial responses to stress.

Main Methods:

• Literature review of studies investigating the interplay between host stress and bacterial infections.
• Analysis of research on neuroendocrine hormone effects on host immunity and bacterial physiology.
• Examination of bacterial responses to stress-related signals, including catecholamines.

Main Results:

• Stress hormones affect host susceptibility through immune modulation and direct impacts on bacterial virulence factors.
• Catecholamines can influence bacterial growth, motility, biofilm formation, and pathogenicity.
• Quorum sensing mechanisms regulate the response of certain bacteria (e.g., Salmonella, E. coli, P. aeruginosa) to stress signals.

Conclusions:

• Host stress significantly influences bacterial infection outcomes through both indirect immune effects and direct bacterial modulation.
• Understanding these stress-bacterial interactions is crucial for managing infectious diseases in animals.
• Bacterial responses to host stress signals, particularly mediated by quorum sensing, represent a key area for further research.