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The effects of daptomycin on cell wall biosynthesis in Enterococcal faecalis
Binayak Rimal1,2, James Chang3, Chengyin Liu4
1Institute of Biomedical Studies, Baylor University, Waco, TX, 76798, USA.
Scientific Reports
|July 28, 2023
Summary
Daptomycin treatment thins bacterial cell walls by disrupting peptidoglycan crosslinking and maturation, not by inhibiting precursor synthesis. This leads to increased susceptibility to degradation, impacting multidrug-resistant Gram-positive infections.
Area of Science:
- Microbiology
- Antibiotic Resistance
- Biochemistry
Background:
- Daptomycin is a crucial antibiotic for treating infections caused by multidrug-resistant Gram-positive bacteria.
- Its known mechanisms include bacterial membrane depolarization, but its precise effects on cell wall biosynthesis require further clarification.
Purpose of the Study:
- To elucidate the detailed mechanism of daptomycin's action on bacterial cell wall biosynthesis.
- To investigate whether daptomycin inhibits peptidoglycan precursor synthesis or affects cell wall maturation.
Main Methods:
- Utilized 15N cross-polarization magic-angle spinning NMR on *Staphylococcus aureus* to analyze cell wall components.
- Employed liquid chromatography-mass spectrometry to quantify peptidoglycan modifications in *Enterococcus faecalis*.
Main Results:
- Daptomycin treatment led to cell wall thinning in *S. aureus* without accumulating peptidoglycan precursors.
- In *E. faecalis*, daptomycin significantly reduced peptidoglycan crosslinking and stem modifications, increasing lytic transglycosylase activity.
- NMR data indicated no inhibition of the transglycosylation step in peptidoglycan biosynthesis.
Conclusions:
- Daptomycin inhibits bacterial cell wall biosynthesis by impeding the incorporation and maturation of peptidoglycan, rather than inhibiting precursor synthesis.
- This disruption makes the cell wall susceptible to autolytic degradation, contributing to the antibiotic's efficacy against resistant pathogens.
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