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Isolation and Identification of Waterborne Antibiotic-Resistant Bacteria and Molecular Characterization of their Antibiotic Resistance Genes
Published on: March 3, 2023
Genetic basis for daptomycin resistance in enterococci.
Kelli L Palmer1, Anu Daniel, Crystal Hardy
1Departments of Ophthalmology and Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, USA.
Antimicrobial Agents and Chemotherapy
|April 20, 2011
Summary
Multidrug-resistant enterococci pose a significant threat. This study identified key genetic mutations, particularly in the EF0631 gene, leading to daptomycin resistance in Enterococcus faecalis, offering insights into treatment strategies.
Area of Science:
- Microbiology
- Genetics
- Infectious Diseases
Background:
- Multidrug-resistant enterococci are a major cause of hospital-acquired infections.
- Understanding genetic adaptations to antibiotics like daptomycin is crucial for public health.
- Daptomycin resistance in enterococci is rare but emerging.
Purpose of the Study:
- To investigate the genetic mechanisms of daptomycin resistance in Enterococcus faecalis.
- To identify mutations conferring resistance through experimental evolution and whole-genome sequencing.
Main Methods:
- Serial passage of multidrug-resistant Enterococcus faecalis V583 in the presence of daptomycin.
- Whole-genome resequencing of evolved daptomycin-resistant strains.
- Comparative genomic analysis to identify fixed mutations.
Main Results:
- Identified seven candidate daptomycin resistance genes and three distinct mutational pathways.
- Mutations in EF0631, encoding a putative cardiolipin synthase, were consistently found in evolved and clinical resistant strains.
- EF0631 alleles from resistant strains conferred resistance in a susceptible host.
Conclusions:
- A novel mechanism of enterococcal daptomycin resistance involving EF0631 mutations was elucidated.
- This mechanism is distinct from that observed in staphylococci.
- Alternative resistance pathways independent of EF0631 also exist in clinical isolates.
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