[Linezolid-resistant Enterococcus faecium: the first G2576T mutation in Turkey]

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Linezolid, an oxazolidinone antibiotic, is crucial for treating gram-positive coccal infections, including those caused by multidrug-resistant pathogens like vancomycin-resistant enterococci (VRE).
• The emergence of linezolid resistance poses a significant threat to the effective management of VRE infections globally.

Observation:

• A case study involving a 66-year-old paraplegic woman with a decubitis ulcer infection revealed the presence of Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus faecium.
• Despite empirical antibiotic therapy, the patient's condition worsened, necessitating intensive care.
• Blood cultures after three weeks of linezolid treatment identified linezolid- and vancomycin-resistant E. faecium.

Findings:

• Molecular analysis, including polymerase chain reaction and sequence analysis, confirmed linezolid resistance in the VRE strain.
• 16S rRNA sequencing identified the resistant isolates as E. faecium, with both possessing a G2576U mutation in the 23S rRNA gene.
• This finding represents a new instance of linezolid resistance in vancomycin-resistant E. faecium in Turkey, following a previously reported G2576T mutation.

Implications:

• The emergence of linezolid-resistant VRE strains in Turkey necessitates increased vigilance and careful monitoring during linezolid treatment.
• Understanding the genetic basis of linezolid resistance (e.g., G2576U mutation) is critical for developing strategies to combat antimicrobial resistance.
• This underscores the urgent need for continued surveillance and research into novel therapeutic approaches against resistant Gram-positive pathogens.