Infections due to vancomycin-resistant Enterococcus faecium resistant to linezolid

Linezolid is a new oxarolidinone antibiotic used to treat infections caused by vancomycin-resistant enterococci (VRE). In early clinical trials, emerg ence of resistance occurred rarely. We report clinical details and antibiot ic susceptibility from five patients treated with linezolid for VRE infecti ons who had resistant organisms isolated during therapy. Four were transpla nt patients receiving protracted courses of the drug; three cases were asso ciated with treatment failure. One of 45 linezolid treated patients develop ed resistance during therapy. Susceptibility testing should be done in all cases on starting therapy.