Table 1 In vitro activity of rifaximin and comparator antimicrobial agents against 257 K. pneumoniae clinical isolates according to their resistance phenotype.

From: An animal model of limitation of gut colonization by carbapenemase-producing Klebsiella pneumoniae using rifaximin

Phenotype

Antimicrobial agent

MIC (μg/ml)

% of inhibited isolates

Range

MIC50

MIC90

KPC (n = 188)

Amikacin (8)

1 to > 128

 > 128

 > 128

11.7

Meropenem (8)

8 to > 32

32

 > 32

0

Tigecycline (2)

0.06 to > 32

2

 > 32

74.4

Colistin (≤ 2)

0.015 to > 32

16

 > 32

45.7

Rifaximin

8 to > 2000

125

2000

84.0

OXA-48 (n = 69)

Amikacin (8)

8 to > 128

 > 128

 > 128

10.1

Meropenem (8)

8 to > 32

32

 > 32

0

Tigecycline (2)

0.015 to > 32

2

 > 32

79.7

Colistin (≤ 2)

0.03 to > 32

16

 > 32

34.8

Rifaximin

32 to > 2000

125

2000

86.9

  1. EUCAST European Committee on Antimicrobial Susceptibility Testing, MIC minimum inhibitory concentration, MIC50/90 MIC required to inhibit 50% and 90% of the isolates, respectively.
  2. The EUCAST breakpoint is provided in parentheses, where available. For Tigecycline the epidemiological cut-off value (ECOFF) is provided.
  3. The breakpoint for rifaximin was set to a clinically meaningful concentration of 1000 μg/ml.
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