Table 2.
In Vitro Susceptibility to Six Aminoglycosides in Klebsiella pneumoniae Producing Extended Spectrum β-Lactamase Stratified by Year of Collection
| K. pneumoniae-ESBL collected in 2000 (n = 70) | K. pneumoniae-ESBL collected in 2006 (n = 69) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Aminoglycoside | EUCAST clinical breakpointsa | Range | MIC50 (mg/L) | MIC90 (mg/L) | Intermediate | Resistant (%) | Range | MIC50 (mg/L) | MIC90 (mg/L) | Intermediate | Resistant (%) | p |
| Gentamicin | >4 | <0.125 to 128 | 8 | 64 | 8 | 37 (52.9) | <0.125 to 128 | 8 | 128 | 1 | 39 (56.5) | 0.8868 |
| Tobramycin | >4 | <0.125 to 128 | 4 | 32 | 14 | 34 (48.5) | <0.125 to 128 | 8 | 32 | 6 | 45 (65.2) | 0.3254 |
| Amikacin | >16 | 0.25 to 32 | 1 | 8 | 5 | 1 (1.4) | 0.25 to 32 | 1 | 8 | 3 | 1 (1.4) | |
| Kanamycinb | >8 | 0.5 to >256 | 4 | 128 | NA | 24 (34.3) | 0.5 to >256 | 32 | >256 | NA | 37 (56.30) | 0.1681 |
| Neomycinb | >8 | <0.125 to 16 | 0.25 | 1 | NA | 1 (1.4) | <0.125 to 16 | 0.25 | 32 | NA | 12 (17.4) | 0.0055 |
| Netilmicin | >4 | <0.125 to 128 | 4 | 32 | 9 | 36 (51.4) | <0.125 to 128 | 8 | 32 | 7 | 39 (56.5) | 0.7757 |
Statistically significant values are in bold type.
a
The clinical breakpoints and ECOFFs are done according to the EUCAST guidelines (www.escmid.org/sites).
b
For kanamycin and neomycin, we used EUCAST ECOFFs.