Pathogen espionage: multiple bacterial adrenergic sensors eavesdrop on host communication systems.

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• Interkingdom Communication

Background:

• Bacterial pathogens interact with eukaryotic hosts, influencing infection outcomes.
• Pathogens use molecular sensors to adapt to host environments and navigate mammalian systems.
• Quorum sensing (QS) involves bacterial communication via autoinducers (AIs), with recent findings on AI-3 and host neuroendocrine (NE) hormone cross-talk.

Purpose of the Study:

• To investigate how enteric bacteria sense and respond to host NE stress hormones (adrenaline and noradrenaline).
• To explore the mechanisms underlying bacterial modulation of virulence in response to host signals.
• To propose alternative bacterial receptors involved in sensing adrenergic signals.

Main Methods:

• Review of existing evidence on bacterial sensing of host NE hormones.
• Analysis of adrenergic receptor antagonist effects on bacterial responses.
• Hypothesizing alternative bacterial adrenergic receptors and signaling cascades.

Main Results:

• Enteric bacteria sense and respond to host adrenaline and noradrenaline to modulate virulence.
• Bacterial responses to adrenergic signals are inhibited by α and β-adrenergic receptor antagonists.
• QseC is a proposed adrenergic receptor in Escherichia coli O157:H7 and Salmonella, but not all responses require it.

Conclusions:

• Evidence suggests alternative bacterial adrenergic receptors, including BasS, QseE, and CpxA, exist.
• These alternative receptors and their signaling cascades play significant roles in interkingdom communication.
• Understanding these pathways is vital for controlling bacterial infections.