Table 4

Comparison of daptomycin MICs by strain and testing methoda

Strain/clonal complexNo. (%) of isolatesMedian (IQR) daptomycin MIC (mg/liter)b
Etest at time of isolationEtest on frozen isolates
CC22-MRSA IV151 (73)0.125 (0.094–0.19)0.125 (0.094–0.125)
CC30 (ST36)-MRSA II21 (10)0.25 (0.125–0.25)0.125 (0.094–0.19)
Weighted avg (CC22 and CC30)0.125 (0.094–0.19)0.125 (0.094–0.19)
CC45 (ST45)-MRSA II16 (8)
CC5-MRSA IV9 (4)0.250 (—)0.19 (0.125–0.19)
CC8/SM108/SM1223 (1)0.250 (—)0.19 (0.19–0.25)
Weighted avg (CC45, CC5, and CC8)0.250 (0.125–0.250)0.19 (0.125–0.19)
  • a All strains were compared by the Kruskal-Wallis test, and the P values were 0.047 and 0.012 for Etest at time of isolation and Etest on frozen isolates, respectively. CC22/CC30 and CC45/CC5/CC8 strains were compared by the Mann-Whitney U test, and the P values were 0.004 and 0.003 for Etest at time of isolation and Etest on frozen isolates, respectively.

  • b IQR, interquartile range. —, numbers were too small for valid calculation.