Salmonella persisters undermine host immune defenses during antibiotic treatment

Area of Science:

• Microbiology
• Immunology
• Bacterial Pathogenesis

Background:

• Antibiotic-tolerant persister cells contribute to persistent and relapsing bacterial infections.
• Persisters are typically considered dormant, but their state within host cells like macrophages is unclear.

Purpose of the Study:

• To investigate the physiological state of Salmonella persisters during macrophage infection.
• To elucidate the mechanisms by which these persisters survive within macrophages.

Main Methods:

• Analysis of Salmonella persister cell activity within infected macrophages.
• Investigation of effector proteins secreted by the Salmonella pathogenicity island 2 type 3 secretion system.
• Assessment of macrophage immune responses and polarization.

Main Results:

• Salmonella persisters within macrophages are metabolically active, not dormant.
• Secreted effectors reprogram macrophages, dampening inflammation and promoting anti-inflammatory polarization.
• This reprogramming facilitates prolonged survival of non-growing Salmonella persisters.

Conclusions:

• Salmonella persisters actively manipulate host macrophages for survival.
• Immune reprogramming by persisters is a key factor in bacterial persistence and potential relapse.
• Targeting persister-host interactions may offer new therapeutic strategies.