Sequential linezolid-resistant Staphylococcus epidermidis isolates with G2576T mutation.

We report on an analysis of sequential isolates of Staphylococcus epidermidis from cultures of blood obtained from a patient with acute myeloid leukemia while the patient was receiving linezolid treatment. All 12 isolates had a linezolid MIC of 32 microg/ml. A 420-bp domain V region of the 23S rRNA gene from all isolates was amplified, and their nucleotide sequences were determined. A G2576T mutation was identified in all isolates. It was estimated that 67% of the 23S rRNA genes carried this mutation. This is the first report of the failure of linezolid treatment for Staphylococcus epidermidis bacteremia associated with a G2576T mutation in an immunocompromised patient.