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Table 2 MIC concordance of different assays compared to the reference BMD method

From: Colistin resistance in Gram-negative bacteria analysed by five phenotypic assays and inference of the underlying genomic mechanisms

Method BMD Vitek 2® UMIC Colistin E-test MIC strip
Specie No. Isolates tested No. Isolates tested No. of concordant isolates [%]a No. Isolates tested No. of concordant isolates [%]a No. Isolates tested No. of concordant isolates [%]a
Acinetobacter spp. 7 4 4 [100.0] 7 7 [100.0] 7 6 [85.7]
C. koseri 3 3 3 [100.0] 3 2 [66.7] 3 2 [66.7]
K. aerogenes 2 2 1 [50.0] 2 1 [50.0] 2 2 [100.0]
E. cloacae 5 5 3 [60.0] 5 5 [100.0] 5 3 [60.0]
E. coli 24 24 17 [70.8] 24 19 [79.2] 24 13 [54.2]
Hafnia spp. 15 15 14 [93.3] 15 14 [93.3] 15 13 [86.7]
K. oxytoca 3 3 1 [33.3] 3 3 [100.0] 3 1 [33.3]
K. pneumoniae 20 19 16 [84.2] 20 17 [85.0] 20 13 [65.0]
P. aeruginosa 10 8 7 [87.5] 10 10 [100.0] 10 8 [80.0]
Total 97 91 66 [72.5] 97 78 [80.4] 97 61 [62.9]
  1. BMD Broth microdilution method
  2. aConcordance was considered as the same MIC value or as one titre difference to that of the reference value obtained by BMD