Related Experiment Videos
Gene dosage and linezolid resistance in Enterococcus faecium and Enterococcus faecalis
S H Marshall1, C J Donskey, R Hutton-Thomas
1Research and Medical Services, Department of Veterans Affairs Medical Center and Division of Infectious Diseases, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
Antimicrobial Agents and Chemotherapy
|September 18, 2002
Summary
Linezolid resistance in enterococci is linked to a specific mutation (G2576U) in the 23S rRNA gene. More mutated genes correlated with higher resistance levels in clinical isolates.
Area of Science:
- Microbiology
- Molecular Biology
- Antimicrobial Resistance
Background:
- Linezolid is a crucial antibiotic for treating infections caused by Gram-positive bacteria, including resistant strains.
- Emergence of linezolid resistance poses a significant threat to its clinical utility.
- A specific mutation, G2576U, in the 23S ribosomal RNA (rRNA) gene has been implicated in linezolid resistance.
Purpose of the Study:
- To investigate the correlation between the G2576U mutation in the 23S rRNA gene and the level of linezolid resistance in clinical enterococcal isolates.
- To determine if the number of 23S rRNA alleles carrying the mutation influences the degree of resistance.
Main Methods:
- Analysis of nine clinical isolates of linezolid-resistant enterococci.
- Genomic analysis to identify the presence and number of G2576U mutations in the 23S rRNA genes.
- Phenotypic susceptibility testing to determine the level of linezolid resistance.
Main Results:
- A direct association was observed between the number of 23S rRNA genes harboring the G2576U mutation and the expressed level of linezolid resistance.
- Enterococcal isolates with a higher proportion of mutated 23S rRNA genes exhibited greater resistance to linezolid.
Conclusions:
- The G2576U mutation in the 23S rRNA gene is a key genetic determinant of linezolid resistance in enterococci.
- The level of resistance is quantitatively related to the number of mutated 23S rRNA alleles present in the bacterial population.