Table 2.
CPE classification as detected by MALDI-TOF with IPM, EDTA, and PB.
| Genotype (n) | IPM: near 479 m/za | adding EDTAc IPM: near 479 m/z | adding PBd IPM: near 479 m/z | adding EDTA and PB IPM: near 479 m/z | ||||
|---|---|---|---|---|---|---|---|---|
| Peak appearance | No peak appears | Peak appearance | No peak appears | Peak appearance | No peak appears | Peak appearance | No peak appears | |
| KPC-2 (53) | 0 | 53 | 0 | 53 | 53 | 0 | 53 | 0 |
| NDM-1 (30) | 0 | 30 | 30 | 0 | 0 | 30 | 30 | 0 |
| VIM-1 (9) | 0 | 9 | 9 | 0 | 0 | 9 | 9 | 0 |
| IMP-1 (8) | 0 | 8 | 8 | 0 | 0 | 8 | 8 | 0 |
| IMP-2 (4) | 0 | 4 | 4 | 0 | 0 | 4 | 4 | 0 |
| KPC-2/NDM-1 (4) | 0 | 4 | 0 | 4 | 0 | 4 | 4 | 0 |
| OXA-48 (2) | 2 | 0 | 2 | 0 | 2 | 0 | 2 | 0 |
| Non-CPE (72)b | 72 | 0 | 72 | 0 | 72 | 0 | 72 | 0 |
a, CPE hydrolyzes IPM, no peak appears. b, Non-CPE does not hydrolyze IPM, peak appears. c, EDTA inhibits metalloenzymes, peak reappears. d, PB inhibits serinase, peak reappears.