TABLE 2.

Antimicrobial susceptibilities of Enterococcus faecium blood isolates collected from the Ramón y Cajal Hospital (1995 to 2002)

AntibioticIsolate typeMIC (μg/ml)aNonsusceptibility (%)b
Range50%90%
AmpicillinAREF16-12864128100
ASEF<0.12-8140
CiprofloxacinAREF<0.5-1643271
ASEF<0.5-324822
ErythromycinAREF<0.25->128>128>12886
ASEF<0.25->1284>12840
Streptomycin (HLR)AREF≤125-≥2,000≥2,000≥2,00065
ASEF≤125-≥2,000≤1251,00012
Kanamycin (HLR)AREF≤125-≥2,00012512585
ASEF≤125-≥2,00012512512
Gentamicin (HLR)AREF≤125-≥50012512511
ASEF≤125-≥5001251250
VancomycinAREF<0.5->256<0.513
ASEF<0.5->2<0.510
TeicoplaninAREF<0.5->256<0.5<0.53
ASEF<0.5-0.5<0.5<0.50
Quinupristin-dalfopristinAREF<0.5-1641650
ASEF<0.5-42425
LinezolidAREF0.5-4220
ASEF1-4220
ChloramphenicolAREF4-32486
ASEF<0.5-32883
TetracyclineAREF<0.25->1280.25>12824
ASEF<0.5->320.256424
  • a 50% and 90%, MICs at which 50 and 90% of isolates are inhibited, respectively.

  • b Differences in susceptibility to ciprofloxacin, HLR to streptomycin, and HLR to kanamycin among AREF and ASEF isolates were statistically significant (P < 0.001). Differences in susceptibility to erythromycin among AREF and ASEF isolates were statistically significant (P < 0.005).