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.