Table I
Species distribution of different carbapenemase types among non-CP-CRE and 3GCeRE isolates.
| Category (n) | Species | |||||||
|---|---|---|---|---|---|---|---|---|
| Kpn | Eco | Ecl | Kae | Cfr | Pre | Pmi | Sma | |
| KPC (107) | 104 | 1 | 0 | 1 | 1 | 0 | 0 | 0 |
| MBL (36) | ||||||||
| NDM (30) | 7 | 15 | 1 | 0 | 1 | 4 | 1 | 1 |
| IMP (6) | 3 | 0 | 3 | 0 | 0 | 0 | 0 | 0 |
| OXA-48-like (1) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| KPC+NDM (1) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Non-CP-CRE (18) | 8 | 5 | 2 | 3 | 0 | 0 | 0 | 0 |
| 3GCeRE (90) | 17 | 47 | 7 | 10 | 2 | 1 | 4 | 2 |
| Total (253) | 141 | 68 | 13 | 14 | 4 | 5 | 5 | 3 |
Fig. 1.
The inhibitory zone diameter distribution of a) imipenem, b) meropenem for Enterobacterales isolates tested.
Fig. 2.
Flow diagram of the mCDT for distinguishing CRE from CSE isolates, and differentiating KPC and/or MBL producers.
A – imipenem disk alone, B – imipenem disk plus 5 µl EDTA, C – imipenem disk plus 10 µl APB and D – imipenem disk plus 5 µl EDTA and 10 µl APB.
Fig. 3.
Examples of mCDT showing the inhibitory zone diameters of A, B, C, and D for a) a plate 7, 7, 14, and 15 mm confirming the KPC-producing isolate, and for b) a plate 9, 17, 8, 18 mm confirming the MBL-producing isolate.
A – imipenem disk alone, B – imipenem disk plus 5 µl EDTA, C – imipenem disk plus 10 µl APB and D – imipenem disk plus 5 µl EDTA and 10 µl APB.
Table II
Accuracy of detecting KPC or MBL carbapenemases among 163 CRE isolates under different conditions.
| Category | Carbapenemase | Accuracy | |
|---|---|---|---|
| Sensitivity (%), (95% CI) | Specificity (%), (95% CI) | ||
| IPM-5 μ APB | KPC | 88.8 (80.9-93.8) | 100 (92.0-100) |
| IPM-5 μ EDTA | MBL | 100 (88.0-100) | 100 (96.3-100) |
| IPM-10 μ APB | KPC | 97.2 (91.4-99.3) | 100 (92.0-100) |
| IPM-10 μ EDTA | MBL | 100 (88.0-100) | 100 (96.3-100) |
| MEM-5 μ APB | KPC | 48.6 (38.9-58.4) | 100 (92.0-100) |
| MEM-5 μ EDTA | MBL | 100 (88.0-100) | 100 (96.3-100) |
| MEM-10 μ APB | KPC | 59.8 (49.9-69.0) | 100 (92.0-100) |
| MEM-10 μ EDTA | MBL | 100 (88.0-100) | 100 (96.3-100) |