Daptomycin resistant Enterococcus faecalis has a mutation in liaX, which encodes a surface protein that inhibits the...

Area of Science:

• Microbiology
• Genomics
• Infectious Diseases

Background:

• Daptomycin is a crucial antibiotic for treating Gram-positive bacterial infections.
• Increasing resistance to daptomycin, particularly in Enterococcus species, poses a significant public health threat.
• The precise mechanisms underlying daptomycin resistance are not fully elucidated.

Observation:

• A clinical isolate of Enterococcus faecalis was identified in a patient with diabetic ulcers undergoing daptomycin therapy.
• This isolate exhibited resistance to daptomycin.

Findings:

• Whole-genome sequencing revealed a loss-of-function point mutation in the liaX gene within the daptomycin-resistant E. faecalis isolate.
• The identified liaX mutation is associated with the DAP-sensing surface protein, potentially disrupting the LiaFSR regulatory system.
• This mutation is implicated in altered cell membrane remodeling, contributing to daptomycin resistance.

Implications:

• This case represents the first documented instance of clinical daptomycin-resistant Enterococcus faecalis associated with a mutation in liaX.
• Understanding this novel resistance mechanism is critical for developing strategies to combat daptomycin resistance.
• Further research into the liaX gene and its role in daptomycin resistance is warranted for effective treatment of resistant infections.