cGAS/STING sensing in dendritic cells discriminates between daptomycin sensitive and resistant Staphylococcus aureus...

Area of Science:

• Microbiology
• Immunology
• Infectious Diseases

Background:

• Antimicrobial resistance (AMR) poses a significant global health threat, with MRSA being a common pathogen.
• MRSA frequently develops resistance to last-line antibiotics like daptomycin through genetic mutations.
• These resistance mechanisms can alter bacterial cell structures, impacting host immune responses.

Purpose of the Study:

• To investigate how daptomycin resistance in MRSA affects innate immune sensing by dendritic cells (DCs).
• To elucidate the specific mechanisms by which resistant MRSA evades DC recognition and activation.

Main Methods:

• Comparative analysis of daptomycin-susceptible and daptomycin-resistant MRSA strains.
• Assessment of phagocytosis efficiency by DCs.
• Evaluation of the cytoplasmic cGAS/STING pathway activation in DCs upon encountering resistant MRSA.

Main Results:

• Daptomycin-resistant MRSA exhibited reduced phagocytosis by DCs compared to susceptible strains.
• Resistant MRSA impaired the recognition of bacterial isolates via the cGAS/STING pathway.
• This impairment affected the production of cyclic dinucleotides by both host and bacterium.

Conclusions:

• MRSA's acquisition of daptomycin resistance impedes innate immune sensing by DCs.
• Resistance mutations concurrently hinder the innate immune system's ability to recognize and respond to bacteria.
• This dual effect highlights a critical mechanism of immune evasion by antibiotic-resistant pathogens.