Table 4: MIC distribution of gentamicin determined by the E-test and the genotypic profiles.
Resistance pattern |
Distribution of MIC of gentamicin (µg/mL)* |
No. (%) |
R |
S |
≤ 4 |
8 |
16 |
32 |
64 |
128 |
256 |
≥ 512 |
79 (92.9%) |
6 (7.1%) |
6 |
0 |
10 |
18 |
22 |
14 |
6 |
9 |
Genotypic profile |
aacC1 alone (2)** |
- |
- |
- |
- |
2 |
- |
- |
- |
aadA1 alone (1) |
- |
- |
- |
1 |
- |
- |
- |
- |
aadB alone (1) |
- |
- |
1 |
- |
- |
- |
- |
- |
aphA6 alone (15) |
- |
- |
7 |
4 |
- |
- |
4 |
- |
aacC1 + aadA1 + aadB + aphA6 (5) |
- |
- |
- |
- |
2 |
1 |
2 |
- |
aacC1 + aadA1 + aphA6 (24) |
- |
- |
- |
1 |
12 |
2 |
- |
9 |
aadA1 + aadB + aphA6 (2) |
- |
- |
- |
2 |
- |
- |
- |
- |
aacC1 + aadA1 (8) |
- |
- |
2 |
- |
- |
6 |
- |
- |
aadA1 + aphA6 (3) |
- |
- |
- |
3 |
- |
- |
- |
- |
aadB + aphA6 (10) |
- |
- |
- |
7 |
- |
3 |
- |
- |
aadB + aphA6 (5) |
- |
- |
- |
- |
4 |
1 |
- |
- |
aacC1 + aadB (3) |
- |
- |
- |
- |
2 |
1 |
- |
- |
*MIC of gentamicin (µg/mL) among A. baumannii isolates according to CLSI breakpoints: MIC ≤ 4 μg/mL for susceptible (S) and MIC ≥ 16 μg/mL for resistant (R).
**Number of isolates harbor the genotypic profile.