TABLE 2.
Prevalence of aminoglycoside-modifying enzyme gene combinations in 144 Escherichia coli isolates resistant to aminoglycosides in relation to aminoglycoside MICsa
| AME gene(s) | No. (%) of isolates | MIC50/MIC90 (mg/liter) |
Range |
No. (%) of resistant isolates |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AMK | GEN | TOB | PLZ | AMK | GEN | TOB | PLZ | AMK | GEN | TOB | PLZ | ||
| aac(6′)Ib | 64 (44.4) | 8/16 | 2/>64 | 16/32 | 1/1 | 2 to 64 | 0.5 to >64 | 8 to 64 | 0.25 to 4 | 2 (3.1) | 24 (37.5) | 64 (100) | NA |
| aac(3)IIa | 21 (14.5) | 4/4 | >64/>64 | 8/8 | 1/1 | 2 to 8 | 64 to >64 | 4 to 32 | 0.5 to 2 | 0 (0) | 21 (100) | 19 (90.5) | NA |
| aph(3′)Ia | 9 (6.3) | 4/8 | 64/64 | 8/32 | 0.5/2 | 2 to 8 | 2 to 64 | 4 to 32 | 0.5 to 2 | 0 (0) | 8 (88.9) | 7 (77.8) | NA |
| ant(2″)Ia | 4 (2.8) | 2/4 | 64/64 | 8/32 | 0.5/1 | 2 to 4 | 64 to 64 | 8 to 32 | 0.5 to 1 | 0 (0) | 4 (100) | 4 (100) | NA |
| aa(6′)Ib + aph(3′)Ia | 13 (9.02) | 8/16 | 64/64 | 32/32 | 1/1 | 4 to 64 | 0.5 to >64 | 16 to 32 | 0.5 to 1 | 1 (7.7) | 8 (61.5) | 13 (100) | NA |
| aac(6′)Ib + ant(2″)Ia | 7 (4.9) | 8/32 | 32/64 | 32/64 | 1/4 | 2 to 32 | 8 to 64 | 8 to 64 | 0.5 to 4 | 1 (14.3) | 7 (100) | 7 (100) | NA |
| aac(6′)Ib + aac(3)IIa | 5 (3.5) | 8/>64 | >64/>64 | 32/>64 | 0.5/1 | 2 to >64 | 64 to >64 | 16 to >64 | 0.5 to 1 | 1 (20) | 5 (100) | 5 (100) | NA |
| aac(3)IIa + ant(2″)Ia | 5 (3.5) | 4/4 | 64/64 | 8/8 | 1/1 | 2 to 4 | 64 to 64 | 4 to 8 | 0.5 to 1 | 0 (0) | 5 (100) | 4 (80) | NA |
| aac(3)IIa + aph(3′)Ia | 4 (2.8) | 2/4 | 64/>64 | 8/8 | 0.5/1 | 2 to 4 | 64 to >64 | 8 to 8 | 0.5 to 1 | 0 (0) | 4 (100) | 4 (100) | NA |
| ant(2″)Ia + aph(3′)Ia | 2 (1.4) | 2/4 | 64/>64 | 16/16 | 0.5/1 | 2 to 4 | 64 to >64 | 16 to 16 | 0.5 to 1 | 0 (0) | 2 (100) | 2 (100) | NA |
| aac(6′)Ib + aac(3)Iia + aph(3′)Ia | 1 (0.7) | 8/8 | 32/32 | 16/16 | 1/1 | 8 to 8 | 32 to 32 | 16 to 16 | 1 to 1 | 0 (0) | 1 (100) | 1 (100) | NA |
| aac(3)IIa + ant(2″)Ia + aph(3′)Ia | 1 (0.7) | 8/8 | >64/>64 | 16/16 | 2/2 | 8 to 8 | >64 to >64 | 16 to 16 | 2 to 2 | 0 (0) | 1 (100) | 1 (100) | NA |
| None | 8 (5.5) | 4/8 | 32/64 | 8/32 | 0.5/2 | 2 to 8 | 1 to 64 | 1 to 32 | 0.5 to 2 | 0 (0) | 7 (87.5) | 5 (62.5) | NA |
a
Resistance data were determined on the basis of EUCAST susceptibility breakpoints. AME, aminoglycoside-modifying enzyme; AMK, amikacin; GEN, gentamicin; TOB, tobramycin; PLZ, plazomicin; NA, not applicable.