Table 2.
In vitro antimicrobial susceptibilities of CRE strains.
| MIC range (μg/ml) | MIC50 (μg/ml) | MIC90 (μg/ml) | Susceptible | Intermediate | Resistant | |
|---|---|---|---|---|---|---|
| TOTAL (n = 134) | ||||||
| Amikacin | ≤0.5->256 | 32 | >256 | 74 (55.2%) | 4 (3.0%) | 56 (41.8%) |
| Gentamicin | ≤0.5->256 | 128 | >256 | 38 (28.4%) | 8 (6.0%) | 88 (65.7%) |
| Tobramycin | ≤0.5->256 | 64 | >256 | 47 (35.1%) | 15 (11.2%) | 72 (53.7%) |
| Apramycin | 0.5->256 | 4 | 8 | 128 (95.5%) | – | 6 (4.5%) |
| Neomycin | 0.5->256 | 8 | 256 | 88 (65.7%) | – | 46 (34.3%) |
| Paromomycin | 0.5->256 | 4 | >256 | 87 (64.9%) | – | 47 (35.1%) |
| Streptomycin | 0.5->256 | 16 | 256 | 106 (79.1%) | – | 28 (20.9%) |
| Imipenem | 2->256 | 64 | 256 | 0 (0.0%) | 2 (1.4%) | 132 (98.6%) |
| Meropenem | 8->256 | 256 | >256 | 0 (0.0%) | 0 (0.0%) | 134 (100%) |
| Piperacillin-tazobactam | 8/4->256/4 | >256/4 | >256/4 | 1 (0.7%) | 2 (1.5%) | 131 (97.8%) |
| Ciprofloxacin | ≤0.5->256 | 128 | >256 | 29 (21.6%) | 5 (3.7%) | 100 (74.6%) |
| Trimethoprim-sulfamethoxazole | ≤0.5/9.5- >128/2432 | >128/2432 | >128/2432 | 31 (23.1%) | – | 103 (76.9%) |
| K. pneumoniae (n = 86) | ||||||
| Amikacin | 1->256 | >256 | >256 | 38 (44.2%) | 3 (3.5%) | 45 (52.3%) |
| Gentamicin | ≤0.5->256 | 256 | >256 | 25 (29.1%) | 1 (1.2%) | 60 (69.8%) |
| Tobramycin | ≤0.5->256 | 256 | >256 | 28 (32.6%) | 8 (9.3%) | 50 (58.1%) |
| Apramycin | 0.5->256 | 4 | 8 | 85 (98.8%) | 0 (0.0%) | 1 (1.2%) |
| Neomycin | 0.5–256 | 4 | 256 | 55 (64.0%) | – | 31 (36.0%) |
| Paromomycin | 0.5->256 | 4 | >256 | 54 (62.8%) | – | 32 (37.2%) |
| Streptomycin | 0.5->256 | 8 | 64 | 81 (94.2%) | – | 5 (5.8%) |
| Imipenem | 2->256 | 128 | 256 | 0 (0.0%) | 1 (1.2%) | 85 (98.8%) |
| Meropenem | 8->256 | 256 | >256 | 0 (0.0%) | 0 (0.0%) | 86 (100%) |
| Piperacillin-tazobactam | 8/4->256/4 | >256/4 | >256/4 | 1 (1.2%) | 2 (2.3%) | 83 (96.5%) |
| Ciprofloxacin | ≤0.5->256 | 128 | >256 | 20 (23.3%) | 3 (3.5%) | 63 (73.3%) |
| Trimethoprim-sulfamethoxazole | ≤0.5/9.5->128/2432 | >128/2432 | >128/2432 | 20 (23.3%) | – | 66 (76.7%) |
| E. coli (n = 25) | ||||||
| Amikacin | 2->256 | 16 | >256 | 18 (72.0%) | 0 (0.0%) | 7 (28.0%) |
| Gentamicin | ≤0.5->256 | 64 | >256 | 5 (20.0%) | 3 (12.0%) | 17 (68.0%) |
| Tobramycin | ≤0.5->256 | 32 | >256 | 8 (32.0%) | 3 (12.0%) | 14 (56.0%) |
| Apramycin | 1->256 | 8 | >256 | 20 (80.0%) | 0 (0.0%) | 5 (20.0%) |
| Neomycin | 1->256 | 8 | 256 | 15 (60.0%) | – | 10 (40.0%) |
| Paromomycin | 1->256 | 8 | >256 | 14 (56.0%) | – | 11 (44.0%) |
| Streptomycin | 2->256 | 128 | >256 | 12 (48.0%) | – | 13 (52.0%) |
| Imipenem | 8->256 | 32 | 128 | 0 (0.0%) | 0 (0.0%) | 25 (100%) |
| Meropenem | 32->256 | 256 | >256 | 0 (0.0%) | 0 (0.0%) | 25 (100%) |
| Piperacillin-tazobactam | >256/4 | >256/4 | >256/4 | 0 (0.0%) | 0 (0.0%) | 25 (100%) |
| Ciprofloxacin | 0.5->256 | >256 | >256 | 1 (4.0%) | 0 (0.0%) | 24 (96.0%) |
| Trimethoprim-sulfamethoxazole | ≤0.5/9.5- 128/2432 | 128/2432 | 128/2432 | 3 (12.0%) | – | 22 (88.0%) |
| E. cloacae (n = 13) | ||||||
| Amikacin | 1->256 | 8 | >256 | 9 (69.2%) | 1 (7.7%) | 3 (23.1%) |
| Gentamicin | 0.5->256 | 32 | >256 | 2 (15.4%) | 4 (30.8%) | 7 (53.8%) |
| Tobramycin | 1->256 | 16 | >256 | 5 (38.5%) | 4 (30.8%) | 4 (30.8%) |
| Apramycin | 1–4 | 4 | 8 | 13 (100%) | 0 (0.0%) | 0 (0.0%) |
| Neomycin | 0.5->128 | 8 | 128 | 11 (84.6%) | – | 2 (15.4%) |
| Paromomycin | 0.5–256 | 4 | 256 | 11 (84.6%) | – | 2 (15.4%) |
| Streptomycin | 2->256 | 128 | >256 | 4 (30.8%) | – | 9 (69.2%) |
| Imipenem | 4–128 | 32 | 128 | 0 (0.0%) | 0 (0.0%) | 13 (100%) |
| Meropenem | 8–256 | 128 | 256 | 0 (0.0%) | 0 (0.0%) | 13 (100%) |
| Piperacillin-tazobactam | >256/4 | >256/4 | >256/4 | 0 (0.0%) | 0 (0.0%) | 13 (100%) |
| Ciprofloxacin | ≤0.5->256 | 32 | >256 | 3 (23.1%) | 1 (7.7%) | 9 (69.2%) |
| Trimethoprim-sulfamethoxazole | ≤0.5/9.5->128/2432 | >128/2432 | >128/2432 | 3 (23.1%) | – | 10 (76.9%) |
| blaKPC−2-CARRYING STRAINS (n = 62) | ||||||
| Amikacin | ≤0.5->256 | >256 | >256 | 18 (29.0%) | 2 (3.2%) | 42 (67.7%) |
| Gentamicin | ≤0.5->256 | >256 | >256 | 9 (14.5%) | 0 (0.0%) | 53 (85.5%) |
| Tobramycin | ≤0.5->256 | 256 | >256 | 10 (16.1%) | 5 (8.1%) | 47 (75.8%) |
| Apramycin | 0.5–8 | 4 | 8 | 62 (100%) | 0 (0.0%) | 0 (0.0%) |
| Neomycin | 0.5–256 | 8 | 256 | 36 (58.1%) | – | 26 (41.9%) |
| Paromomycin | 0.5->256 | 8 | >256 | 36 (58.1%) | – | 26 (41.9%) |
| Streptomycin | 0.5–64 | 8 | 32 | 61 (98.4%) | – | 1 (1.6%) |
| Imipenem | 8->256 | 128 | >256 | 0 (0.0%) | 0 (0.0%) | 62 (100%) |
| Meropenem | 8->256 | >256 | >256 | 0 (0.0%) | 0 (0.0%) | 62 (100%) |
| Piperacillin-tazobactam | 256/4- >256/4 | >256/4 | >256/4 | 0 (0.0%) | 0 (0.0%) | 62 (100%) |
| Ciprofloxacin | ≤0.5->256 | 128 | >256 | 5 (8.1%) | 2 (3.2%) | 55 (88.7%) |
| Trimethoprim-sulfamethoxazole | ≤0.5/9.5- >128/2432 | >128/2432 | >128/2432 | 11 (17.7%) | - | 51 (82.3%) |
| blaNDM-CARRYING STRAINS (n = 66) | ||||||
| Amikacin | 1->256 | 8 | >256 | 51 (77.3%) | 2 (3.0%) | 13 (19.7%) |
| Gentamicin | ≤0.5->256 | 16 | >256 | 26 (39.4%) | 8 (12.1%) | 32 (48.5%) |
| Tobramycin | ≤0.5->256 | 8 | >256 | 33 (50.0%) | 9 (13.6%) | 24 (36.4%) |
| Apramycin | 1->256 | 4 | 8 | 60 (90.9%) | 0 (0.0%) | 6 (9.1%) |
| Neomycin | 0.5->256 | 8 | 256 | 46 (69.7%) | – | 20 (30.3%) |
| Paromomycin | 0.5->256 | 4 | >256 | 45 (68.2%) | – | 21 (31.8%) |
| Streptomycin | 0.5->256 | 16 | >256 | 40 (60.6%) | – | 26 (39.4%) |
| Imipenem | 4->256 | 64 | 128 | 0 (0.0%) | 0 (0.0%) | 66 (100%) |
| Meropenem | 8->256 | 128 | >256 | 0 (0.0%) | 0 (0.0%) | 66 (100%) |
| Piperacillin-tazobactam | 256/4- >256/4 | >256/4 | >256/4 | 0 (0.0%) | 0 (0.0%) | 66 (100%) |
| Ciprofloxacin | 0.5->256 | >256 | >256 | 7 (10.6%) | 2 (3.0%) | 57 (86.4%) |
| Trimethoprim-sulfamethoxazole | ≤0.5/9.5- >128/2432 | >128/2432 | >128/2432 | 17 (25.8%) | – | 49 (74.2%) |