TABLE 2.
Susceptibility rates for aminoglycosides against Enterobacterales isolates from U.S. hospitals applying different breakpoint criteria
| Antimicrobial agent by organism groupa | Breakpoint setting organization |
||||
|---|---|---|---|---|---|
| CLSIb | EUCASTc | USCAST (pneumonia)d | USCASTd | FDAe | |
| Susceptibility breakpoints (mg/liter) | |||||
| Plazomicin | NAf | NA | NA | ≤4 | ≤2 |
| Amikacin | ≤16 | ≤8 | NA | ≤4 | ≤16 |
| Gentamicin | ≤4 | ≤2 | ≤1 | ≤2 | ≤4 |
| Tobramycin | ≤4 | ≤2 | ≤1 | ≤2 | ≤4 |
| Percentage susceptible | |||||
| All Enterobacterales (n = 8,783) | |||||
| Plazomicin | NA | NA | NA | 99.6 | 97.0 |
| Amikacin | 99.4 | 98.5 | NA | 94.2 | 99.4 |
| Gentamicin | 90.1 | 89.5 | 86.8 | 89.5 | 90.1 |
| Tobramycin | 89.9 | 87 | 81 | 87.0 | 89.9 |
| CRE (n = 98) | |||||
| Plazomicin | NA | NA | NA | 98.0 | 95.9 |
| Amikacin | 78.6 | 67.3 | NA | 49.0 | 78.6 |
| Gentamicin | 45.9 | 39.8 | 32.7 | 39.8 | 45.9 |
| Tobramycin | 22.4 | 20.4 | 15.3 | 20.4 | 22.4 |
| MDR (n = 881) | |||||
| Plazomicin | NA | NA | NA | 97.3 | 89.8 |
| Amikacin | 94.3 | 87.3 | NA | 69.4 | 94.3 |
| Gentamicin | 43.9 | 41.4 | 38.3 | 41.4 | 43.9 |
| Tobramycin | 32.1 | 25.5 | 21.0 | 25.5 | 32.1 |
| XDR (n = 102) | |||||
| Plazomicin | NA | NA | NA | 92.2 | 89.2 |
| Amikacin | 72.5 | 61.8 | NA | 43.1 | 72.5 |
| Gentamicin | 30.4 | 23.5 | 16.7 | 23.5 | 30.4 |
| Tobramycin | 7.8 | 1.0 | 0.0 | 1.0 | 7.8 |
| PDR (n = 3) | |||||
| Plazomicin | NA | NA | NA | 100.0 | 100.0 |
| Amikacin | 100.0 | 100.0 | NA | 66.7 | 100.0 |
| Gentamicin | 33.3 | 0.0 | 0.0 | 0.0 | 33.3 |
| Tobramycin | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Nonsusceptible to 2 aminoglycosides (n = 680) | |||||
| Plazomicin | NA | NA | NA | 98.7 | 96.8 |
| Amikacin | 95.6 | 91.0 | NA | 73.2 | 95.6 |
| Gentamicin | 4.4 | 4.1 | 2.2 | 4.1 | 4.4 |
| Tobramycin | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Nonsusceptible to 3 aminoglycosides (n = 23) | |||||
| Plazomicin | NA | NA | NA | 60.9 | 52.2 |
| Amikacin | 0.0 | 0.0 | NA | 0.0 | 0.0 |
| Gentamicin | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |
| Tobramycin | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |