Table 3 Combined activity of colistin with selected antibiotics against pandrug-resistant K. pneumoniae isolates

MIC of COL

16

8

128

512

16

MIC of TGC

8

8

8

8

4

MICs of COL + TGC

MDF

(ΣFICI/Outcome)

4 + 0.5

4 + 16

(0.31/syn)

4 + 0.125

2 + 64

(0.52/add)

16 + 2

8 + 4

(0.38/syn)

64 + 2

8 + 4

(0.38/syn)

2 + 1

8 + 4

(0.38/syn)

MIC of DO

32

32

128

32

8

MICs of COL + DO

MDF

(ΣFICI/Outcome)

2 + 8

8 + 4

(0.38/syn)

2 + 4

4 + 8

(0.38/syn)

2 + 32

64 + 4

(0.27/syn)

2 + 8

256 + 4

(0.25/syn)

2 + 2

8 + 4

(0.38/syn)

MIC of CIP

256

256

8

256

256

MICs of COL + CIP

MDF

(ΣFICI/Outcome)

2 + 4

8 + 64

(0.14/syn)

4 + 4

2 + 64

(0.52/add)

4 + 2

32 + 4

(0.29/syn)

16 + 32

32 + 8

(0.17/syn)

2 + 32

8 + 8

(0.25/syn)

MIC of LE

64

128

8

128

128

MICs of COL + LE

MDF

(ΣFICI/Outcome)

2 + 8

8 + 8

(0.25/syn)

2 + 32

4 + 4

(0.50/syn)

2 + 2

64 + 4

(0.27/syn)

4 + 32

128 + 4

(0.26/syn)

2 + 16

8 + 8

(0.25/syn)

MIC of IPM

32

32

64

16

32

MICs of COL + IPM

MDF

(ΣFICI/Outcome)

8 + 1

2 + 32

(0.53/add)

4 + 16

2 + 2

(1/ind)

8 + 4

16 + 16

(0.13/syn)

32 + 2

16 + 8

(0.19/syn)

8 + 2

2 + 16

(0.56/add)

MIC of MRP

64

128

128

128

128

MICs of COL + MRP

MDF

(ΣFICI/Outcome)

8 + 1

2 + 64

(0.52/add)

4 + 64

2 + 2

(1/ind)

8 + 8

16 + 16

(0.13/syn)

64 + 4

8 + 32

(0.16/syn)

4 + 32

4 + 4

(0.50/syn)

MIC of SXT

1024/19456

1024/19456

1024/19456

512/9728

512/9728

MICs of COL + SXT

MDF

(ΣFICI/Outcome)

2 + 64/1216

8 + 16/16

(0.25/syn)

1 + 128/2432

8 + 8/8

(0.38/syn)

32 + 32/608

4 + 32/32

(0.31/syn)

256 + 64/1216

2 + 8/8

(0.75/add)

4 + 64/1216

4 + 8/8

(0.50/syn)