Table 2.
Results of validation of VITEK MS plus system in identification of VIM- and SPM-type MBL-producing P. aeruginosa isolates using the two SuperSpectra
| Validation strains | No. of strains | Identification by VITEK MS | Confidence values (%) | Percentage |
|---|---|---|---|---|
| VIM-type MBL-PA | 4 | VIM-type MBL-PA | 99.9 | 16.0 |
| 12 | VIM-type MBL-PA | 90.0–99.9 | 48.0 | |
| 9 | VIM-type MBL-PA | 80.0–90.0 | 36.0 | |
| Subtotal | 25 | VIM-type MBL-PA accuracy rate | 100.0 | |
| SPM-type MBL-PA | 5 | SPM-type MBL-PA | 99.9 | 20.0 |
| 8 | SPM-type MBL-PA | 90.0–99.9 | 32.0 | |
| 8 | SPM-type MBL-PA | 80.0–90.0 | 32.0 | |
| 4 | VIM-type MBL-PA | 90.0–99.9 | 16.0 | |
| Subtotal | 25 | SPM-type MBL-PA accuracy rate | 84.0 | |
| Total | 50 | Total accuracy rate | 92.0 |
Note: The validation results showed that all the VIM-type MBL-PA isolates were correctly identified, just four SPM-type MBL-PA isolates were incorrectly identified as VIM-type MBL-PA isolates which got conflicting results in repeat testing by VITEK MS plus system.