Table 4.

Performance of commercial antimicrobial susceptibility test systems with staphylococcal study isolates

Isolate (source)Vancomycin MIC (μg/ml [interpretive category]) with the following commercial susceptibility testing systema:
Broth microdilutionbVitekMicroScan conventionalMicroScan rapidSensititreEtest
S. aureus Mu50 (Japan)8 (I)4 (S)8 (I)>16 (R)4 (S)6 (I)
S. aureus Mu3 (Japan)2 (S)1 (S)≤2 (S)≤2 (S)1 (S)2 (S)
S. aureus Mu3-8R (Japan)8 (I)4 (S)4 (S)≤2 (S)2 (S)4 (S)
S. aureus N20 (Japan)4 (S)1 (S)4 (S)≤2 (S)1 (S)2 (S)
S. aureus 963sm (Michigan)8 (I)4 (S)8 (I)>16 (R)8 (I)8 (I)
S. aureus 966 (Michigan)4 (S)4 (S)8 (I)4 (S)4 (S)8 (I)
S. aureus 992 (New Jersey)8 (I)4 (S)4 (S)≤2 (S)8 (I)6 (I)
S. aureus 803 (Florida)4 (S)4 (S)8 (I)>16 (R)8 (I)4 (S)
S. epidermidis 5289 (Virginia)8 (I)4 (S)8 (I)>16 (R)8 (I)8 (I)
S. epidermidis 759 (Wisconsin)8 (I)4 (S)8 (I)>16 (R)4 (S)8 (I)
S. epidermidis 12333 (California)8 (I)4 (S)8 (I)>16 (R)4 (S)8 (I)
S. haemolyticus 142 (New York)8 (I)4 (S)8 (I)>16 (R)8 (I)8 (I)
  • a The broth microdilution, Sensititre, and Etest results were read visually. The Vitek and MicroScan conventional and rapid results were read by using the respective companies’ instrument. S, susceptible; I, intermediate; R, resistant.

  • b NCCLS reference method.