Table 3 Intensity ratios for 4 peptide markers for 6 test development set isolates.

From: Peptide Markers for Rapid Detection of KPC Carbapenemase by LC-MS/MS

Isolate

KPC

Sample set

GFLAAAVLAR

LTLGSALAAPQR

APIVLAVYTR

LALEGLGVNGQa

ECNIH2

+

A

3.47

2.16

2.89

1.35

ECNIH2

+

B

3.06

1.67

2.61

1.12

ECNIH2

+

C

3.09

1.69

2.52

1.13

ECNIH3

+

A

1.11

0.70

1.03

0.54

ECNIH3

+

B

1.24

0.65

0.99

0.49

ECNIH3

+

C

1.14

0.61

0.91

0.48

E. coli

−

A

0.03

0.00

0.02

0.11

E. coli

−

B

0.02

0.00

0.01

0.10

E. coli

−

C

0.02

0.00

0.02

0.11

K. pneumoniae

−

A

0.03

0.00

0.05

0.03

K. pneumoniae

−

B

0.03

0.00

0.05

0.03

K. pneumoniae

−

C

0.04

0.00

0.04

0.03

KPNIH1

+

A

2.62

2.31

2.80

1.81

KPNIH1

+

B

2.77

1.44

2.23

1.25

KPNIH1

+

C

3.26

1.64

2.54

1.29

KPNIH10

+

A

3.15

2.30

2.63

1.69

KPNIH10

+

B

3.06

1.84

2.75

1.38

KPNIH10

+

C

2.10

1.33

1.67

1.37

Positive range

  

1.11–3.47

0.61–2.31

0.91–2.89

0.48–1.81

Negative range

  

0.02–0.04

<0.01

0.01–0.05

0.03–0.11

Lowest Pos/Neg ratio

  

27.8

>61.0

18.2

4.4

  1. Intensity ratio is calculated as signal peak intensity/daily positive control intensity. Technical triplicate samples (A, B, and C) were prepared at the same time. aBased on b-ions only due to N or Q deamination; this peptide was not used in validation.