TABLE 3.
Mass spectrometry analysis using IMI (atomic mass units)
| β-Lactamase or antibiotic (1:1 ratio) | Mass spectrometry result (AMU) |
||||
|---|---|---|---|---|---|
| Apo | +IMI 1 h | +IMI 2 h | +IMI 4 h | +IMI 24 h | |
| IMI | 299 ± 3 | ||||
| KPC-2 | 28,319 ± 3 | 28,319 ± 3 | 28,319 ± 3 | 28,319 ± 3 | 28,319 ± 3 |
| D179YKPC-2 | 28,366 ± 3 | 28,665 ± 3 | 28,665 ± 3 | 28,665 ± 3 | 28,366 ± 3 (66%), 28,665 ± 3 (34%) |
| KPC-3 | 28,344 ± 3 | 28,344 ± 3 | 28,344 ± 3 | 28,344 ± 3 | 28,344 ± 3 |
| D179YKPC-3 | 28,393 ± 3 | 28,692 ± 3 | 28,692 ± 3 | 28,393 ± 3 (20%), 28,692 ± 3 (80%) | 28,393 ± 3 (95%), 28,692 ± 3 (5%) |