Events

Antibiotic resistance and host immune evasion in Staphylococcus aureus 

Research seminar presented by:

Dr Jhih-Hang Jiang
Senior Research Fellow
Monash University

Abstract:

Staphylococcus aureus remains a significant bacterial pathogen due to its ability to adapt to host immune systems and resist antibiotics. Treating severe methicillin-resistant S. aureus (MRSA) infections often relies on antibiotics like daptomycin, which targets bacterial cell membranes for its bactericidal effects. The rise of daptomycin resistance in MRSA is alarming and often associated with persistent and complicated infections in humans. Our animal model data indicate that S. aureus employs a stealth strategy during mammalian infection that includes simultaneous evasion of antimicrobial action and host immune attack. We have identified that modulation of the bacterial membrane plays a crucial role in S. aureus adaptation in vivo. This response is characterized by changes in anionic membrane phospholipid composition due to point mutations in phospholipid biosynthesis genes, leading to impaired daptomycin penetration and membrane disruption. These mutations also enable S. aureus to evade critical immune responses, including neutrophil chemotaxis, killing by host antimicrobial peptides, and dendritic cell activation. Understanding these molecular mechanisms provide crucial insights into novel therapeutic strategies against this troublesome pathogen.