Linezolid-resistant Enterococcus faecium: The first G2576T mutation in Turkey

Abstract

Linezolid which is the first member of oxazolidinone class of synthetic antimicrobial agents, was licensed for the treatment of gram-positive coccal infections in Turkey in 2006. In recent years, multidrug-resistant pathogens, especially vancomycin-resistant enterococci (VRE), have emerged rapidly worldwide and linezolid exhibited good clinical efficacy against VRE. However, linezolid-resistant bacteria have been reported from Turkey. In April 2011, a 66-year-old paraplegic woman was admitted to our hospital because of an infected decubitis ulcer and empirical antibiotic therapy was started. Since the patient's condition worsened during treatment, she was moved to the intensive care unit. Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium were recovered from tracheal aspirates and blood, respectively. Following three weeks of linezolid therapy blood culture yielded linezolid and vancomycin resistant E.faecium. Linezolid resistance in the VRE strain was confirmed by polymerase chain reaction and sequence analysis, subsequently. Linezolid-resistant two isolates were identified as E.faecium by 16S rRNA sequencing and both isolates had G2576U mutation in 23S rRNA gene. Linezolid resistance which was identified in a vancomycin-resistant E.faecium isolate is a new problem for Turkey. Last year another mutation related to linezolid resistance was reported from Istanbul, Turkey. The isolate had G2576T mutated 235 rRNA genes. Resistance should be considered and closely followed-up during linezolid treatment.