Table 2. Positive rates of the modified Hodge tests of the variable conditions among MBL-producers and non-MBL-producers.
| Types of carbapenem resistance (N of isolates) | N (%) of positive results with two cut offs of indentation levels at each combinations of variables | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| ETP/MHA/0.5 | ETP/MAC/0.5 | MEM/MHA/0.5 | MEM/MAC/0.5 | ETP/MHA/0.05 | ||||||
| ≥2 mm | ≥3 mm | ≥2 mm | ≥3 mm | ≥2 mm | ≥3 mm | ≥2 mm | ≥3 mm | ≥2 mm | ≥3 mm | |
| MBL carbapenemases (33) | 20 (60.6) | 13 (39.4) | 19 (57.6) | 14 (42.4) | 13 (39.4) | 9 (27.3) | 19 (57.6) | 10 (30.3) | 16 (48.5) | 14 (42.4) |
| NDM-1 (25) | 13 (52.0) | 6 (24.0) | 17 (68.0) | 13 (52.0) | 6 (24.0) | 4 (16.0) | 16 (64.0) | 9 (36.0) | 8 (32.0) | 7 (28.0) |
| VIM-2 (7) | 6 (85.7) | 6 (85.7) | 2 (28.6) | 1 (14.3) | 6 (85.7) | 5 (71.4) | 3 (42.9) | 1 (14.3) | 7 (100) | 6 (85.7) |
| Unidentified (1) | 1 (100) | 1 (100) | 0 | 0 | 1 (100) | 0 | 0 | 0 | 1 (100) | 1 (100) |
| No carbapenemase (103) | 15 (14.6) | 6 (5.8) | 22 (21.4) | 13 (12.6) | 5 (4.9) | 1 (1.0) | 10 (9.7) | 3 (2.9) | 13 (12.6) | 8 (7.8) |
| AmpC-CH (58) | 8 (13.8) | 4 (6.9) | 14 (24.1) | 9 (15.5) | 2 (3.4) | 1 (1.7) | 4 (6.9) | 1 (1.7) | 7 (12.1) | 6 (10.3) |
| DHA-1 (19) | 0 | 0 | 1 (5.3) | 1 (5.3) | 0 | 0 | 1 (5.3) | 0 | 0 | 0 |
| ACT -1 (11) | 1 (9.1) | 0 | 1 (9.1) | 0 | 0 | 0 | 0 | 0 | 1 (9.1) | 0 |
| CIT (3) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Unspecified*(25) | 7 (28.0) | 4 (16.0) | 12 (48.0) | 8 (32.0) | 2 (8.0) | 1 (4.0) | 3 (12.0) | 1 (4.0) | 6 (24.0) | 6 (24.0) |
| Other CRE (45) | 7 (15.6) | 2 (4.4) | 8 (17.8) | 4 (8.9) | 3 (6.7) | 0 | 6 (13.3) | 2 (4.4) | 6 (13.3) | 2 (4.4) |
*The term 'unspecified' means that the isolate was negative for all PCR tests performed.
Abbreviations: ETP/MHA/0.5, ertapenem disks on Mueller-Hinton agar with 0.5-McFarland inoculums; ETP/MAC/0.5, ertapenem disks on MacConkey agar with 0.5-McFarland inoculums; MEM/MHA/0.5, meropenem disks on Mueller-Hinton agar with 0.5-McFarland inoculums; MEM/MAC/0.5, meropenem disks on MacConkey agar with 0.5-McFarland inoculums; ETP/MHA/0.05, ertapenem disks on Mueller-Hinton agar with 1:10 dilutions of 0.5-McFarland inoculums. Other abbreviations: See Table 1.