Table 2.
In-vitro antibacterial activity of colistin against 100 CRE isolates using cBMD, E-test, VITEK-2, and RPNP and categorization of errors compared with BMD method.
| cBMD (%) | E-test (%) | VITEK-2 (%) | RPNP (%) | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| EA | CA | ME | VME | SN | SP | EA | CA | ME | VME | SN | SP | EA | CA | ME | VME | SN | SP | CA | ME | VME | SN | SP | |
| E. coli (50) | 94 | 98 | 2.3 | 0 | 100 | 97.6 | 74 | 86 | 9.5 | 37.5 | 62.5 | 88.1 | 86 | 94 | 4.8 | 14.3 | 87.5 | 95.2 | 96 | 2.4 | 12.5 | 100 | 97.6 |
| Klebsiella pneumoniae. (48) | 97.9 | 100 | 0 | 0 | 100 | 100 | 89.5 | 79.2 | 17.1 | 42.9 | 57.1 | 92.7 | 77.1 | 89.6 | 8.9 | 14.3 | 85.7 | 80.5 | 83.3 | 14.6 | 28.6 | 71.4 | 85.4 |
| Enterobacter cloacae (2) | 100 | 100 | 0 | 0 | 100 | 100 | 50 | 100 | 0 | 0 | 100 | 100 | 50 | 100 | 0 | 0 | 100 | 100 | 100 | 0 | 0 | 100 | 100 |
| Total (100) | 96 | 99 | 1.2 | 0 | 100 | 98.8 | 72 | 86 | 9.4 | 40 | 60 | 90.6 | 81 | 88 | 11.8 | 13.3 | 86.7 | 88.2 | 91 | 8.2 | 13.3 | 86.7 | 91.8 |
CA, Categorical agreement; cBMD, Commercial Broth microdilution; EA, Essential agreement; E. coli, Escherichia coli; ME, Major error; MIC, Minimum inhibition concentration; RPNP, Rapid Polymyxin NP; SN, Sensitivity; SP, Specificity; VME, Very major error.