Clonal dissemination of linezolid-resistant Staphylococcus haemolyticus exhibiting the G2576T mutation in the 23S rRNA gene in a tertiary care hospital in Brazil

摘要

In this study, we report the first clonal dissemination of linezolid-resistant Staphylococcus haemolyticus strains with the G2576T mutation in 23S rRNA in Brazil. From March 2008 to January 2010, nine S. haemolyticus strains exhibiting high-level resistance to linezolid (MICs of 32 to 128 fig/ml) were isolated from blood and catheter cultures from different inpatients in a tertiary care hospital. In this institution, linezolid was introduced in November 2000 and is currently the drug of choice for the treatment of VRE infections, which are highly prevalent. Identification testing was performed by the Vitek-2 system (bioMerieux, St. Louis, MO), and the susceptibility of bacterial strains was tested using disk diffusion and agar dilution methods according to the Clinical and Laboratory Standards Institute (CLSI) (1). Etests (AB Biodisk, Solna, Sweden) were used for oxacillin and vanco-mycin. The chromosomal DNA was obtained using the technique of phenol-chloroform extraction. The presence of the cfr gene and mutations in the domain V region of 23S rRNA and the rplC, rplD, and rplV genes were investigated as described previously (2, 4, 9, 10).