In group A compared with group B , there were 53 % fewer gram-positive bloodstream infections ( 15 % [ 9 of 60 ] vs 32 % [ 19 of 60 ] ; difference , -17 % ; 95 % CI , -31 % to -1 % ; P = .03 ) and 64 % fewer central line-associated bloodstream infections ( 3.4 vs 9.4 per 1000 central line days ; ratio , 0.36 ; 95 % CI , 0.16 to 0.81 ; P = .01 ) .