Table 1. Results of the modified Hodge test, Triton Hodge test, Carba NP test, simplified Carba NP test, Blue-Carba NP test, and carbapenem inactivation method with 139 carbapenemase-positive isolates.
| Group (N) | Species (N) | MIC (µg/mL) | N (%) of isolates with positive results of | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| ETP | IPM | MEM | MHT | THT | CNPt | CNPt-direct | BCT | CIM | ||
| Class A | ||||||||||
| KPC-2 (18) | K. pneumoniae (5) | 128–512 | 8–64 | 8–64 | 5 (100) | 5 (100) | 5 (100) | 5 (100) | 5 (100) | 5 (100) |
| E. cloacae (2) | 128 | 8 | 16 | 2 (100) | 2 (100) | 2 (100) | 2 (100) | 2 (100) | 2 (100) | |
| E. coli (7) | 4–16 | 4–16 | 1 | 7 (100) | 7 (100) | 7 (100) | 7 (100) | 7 (100) | 7 (100) | |
| C. koseri (1) | 16 | 8 | 8 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | |
| C. braakii (1) | 32 | 8 | 4 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | |
| C. freundii (2) | 4–16 | 4–16 | 2–8 | 2 (100) | 2 (100) | 2 (100) | 2 (100) | 2 (100) | 2 (100) | |
| All (18) | 18 (100) | 18 (100) | 18 (100) | 18 (100) | 18 (100) | 18 (100) | ||||
| Class B | ||||||||||
| NDM-1 (46) | K. pneumoniae (20) | 1–512 | 0.25–64 | 0.25–32 | 13 (65) | 18 (90) | 20 (100) | 20 (100) | 20 (100) | 20 (100) |
| E. cloacae (17) | 4–256 | 2–64 | 1–32 | 11 (64.7) | 15 (88.2) | 17 (100) | 17 (100) | 17 (100) | 17 (100) | |
| E. coli (3) | 8–16 | 4–16 | 2–8 | 2 (66.6) | 3 (100) | 3 (100) | 3 (100) | 3 (100) | 3 (100) | |
| E. aerogenes (5) | 8–16 | 2–16 | 4–8 | 3 (60) | 5 (100) | 5 (100) | 5 (100) | 5 (100) | 5 (100) | |
| K. oxytoca (1) | 8 | 4 | 2 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | |
| IMP-4 (8) | K. pneumoniae (1) | 64 | 16 | 8 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) |
| E. cloacae (4) | 4 | 0.5–2 | 0.5–1 | 4 (100) | 4 (100) | 4 (100) | 4 (100) | 4 (100) | 4 (100) | |
| K. oxytoca (3) | 4–8 | 2–16 | 2 | 3 (100) | 3 (100) | 3 (100) | 3 (100) | 3 (100) | 3 (100) | |
| IMP-8 (3) | E. cloacae (3) | 4–64 | 1–8 | 1–8 | 3 (100) | 3 (100) | 3 (100) | 3 (100) | 3 (100) | 3 (100) |
| All (57) | 41 (71.9) | 53 (93) | 57 (100) | 57 (100) | 57 (100) | 57 (100) | ||||
| Class D | ||||||||||
| OXA-23 (6) | A. baumannii (6) | - | ≥ 16 | ≥ 16 | 3 (50) | 3 (50) | 1 (16.7) | 5 (83.3) | 4 (66.7) | 4 (66.7) |
| OXA-51-like (13) | A. baumannii (13) | - | ≥ 16 | ≥ 16 | 8 (61.5) | 8 (61.5) | 1 (7.7) | 9 (69.2) | 2 (15.4) | 7 (53.8) |
| OXA-23 + OXA-51-like (32) | A. baumannii (32) | - | ≥ 16 | ≥ 16 | 23 (71.8) | 23 (71.8) | 2 (6.3) | 27 (84.4) | 20 (62.5) | 31 (96.9) |
| All (51) | 34 (66.7) | 34 (66.7) | 4 (7.8) | 41 (80.4) | 26 (51.1) | 42 (82.3) | ||||
| KPC-2 + NDM-1 (10) | K. pneumoniae (5) | 8–64 | 1–32 | 1–8 | 5 (100) | 5 (100) | 5 (100) | 5 (100) | 5 (100) | 5 (100) |
| C. freundii (4) | 64–128 | 16–32 | 8–16 | 3 (75) | 4 (100) | 4 (100) | 4 (100) | 4 (100) | 4 (100) | |
| E. aerogenes (1) | 64 | 32 | 16 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | |
| IMP-8 + NDM-1 (1) | E. cloacae (1) | 128 | 128 | 32 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) |
| KPC-2 + IMP-4 (2) | C. freundii (1) | 32 | 16 | 4 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) |
| C. koseri (1) | 32 | 8 | 8 | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | 1 (100) | |
Abbreviations: ETP, ertapenem; IPM, imipenem; MEM, meropenem; MHT, modified Hodge test; THT, Triton Hodge test; CNPt, Carba NP test; CNPt-direct, simplified Carba NP test; BCT, blue-Carba NP test; CIM, carbapenem inactivation method; KPC, Klebsiella pneumoniae carbapenemases; OXA, oxacillinases; NDM, New Delhi metallo-β-lactamases.