 In the United States , resistance to linezolid has been monitored and tracked since 2004 through a program named LEADER , which ( as of 2007 ) was conducted in 60 medical institutions throughout the country . Resistance has remained stable and extremely low — less than one @-@ half of one percent of isolates overall , and less than one @-@ tenth of one percent of S. aureus samples . A similar , worldwide program — the " Zyvox Annual Appraisal of Potency and Spectrum Study " , or ZAAPS — has been conducted since 2002 . As of 2007 , overall resistance to linezolid in 23 countries was less than 0 @.@ 2 % , and nonexistent among streptococci . Resistance was only found in Brazil , China , Ireland , and Italy , among coagulase @-@ negative staphylococci ( 0 @.@ 28 % of samples resistant ) , enterococci ( 0 @.@ 11 % ) , and S. aureus ( 0 @.@ 03 % ) . In the United Kingdom and Ireland , no resistance was found in staphylococci collected from bacteremia cases between 2001 and 2006 , although resistance in enterococci has been reported . Some authors have predicted that resistance in E. faecium will increase if linezolid use continues at current levels or increases . 
