Table 2.
Activity of aztreonam/avibactam and comparator antimicrobial agents tested against all 1098 CRE isolates combined and the four most common species (2019–21)
| Antimicrobial agent (no. of isolates) | mg/L | CLSI/US FDAa | EUCASTa | ||||||
|---|---|---|---|---|---|---|---|---|---|
| MIC50 | MIC90 | MIC range | %S | %I | %R | %S | %I | %R | |
| All Enterobacterales (1098) | |||||||||
| Aztreonam/avibactamb | 0.25 | 0.5 | ≤0.03 to >16 | (99.6)b | (99.6)b | ||||
| Ceftazidime/avibactam | 2 | >32 | ≤0.015 to >32 | 68.2 | 31.8 | 68.2 | 31.8 | ||
| Meropenem/vaborbactam | 2 | >32 | ≤0.015 to >32 | 60.5 | 3.8 | 35.7 | 64.3 | 35.7 | |
| Ceftolozane/tazobactam | >16 | >16 | 0.25 to >16 | 2.6c | 1.5 | 95.9 | 2.6 | 97.4 | |
| Aztreonam | >16 | >16 | ≤0.03 to >16 | 7.9 | 0.5 | 91.5 | 7.1 | 0.8 | 92.1 |
| Ciprofloxacin | >4 | >4 | ≤0.03 to >4 | 7.7 | 2.0 | 90.3 | 7.7 | 2.0 | 90.3 |
| Levofloxacin | 16 | >32 | ≤0.015 to >32 | 10.4 | 6.7 | 82.9 | 10.4 | 6.7 | 82.9 |
| Gentamicin | 16 | >16 | ≤0.12 to >16 | 44.1 | 3.7 | 52.1 | 41.9d | 58.1 | |
| Amikacin | 8 | >32 | 0.5 to >32 | 64.0 | 9.8 | 26.1 | 53.7d | 46.3 | |
| Minocycline | 4 | >32 | 0.5 to >32 | 57.8 | 16.0 | 26.2 | |||
| Tigecycline | 0.5 | 2 | ≤0.06 to >8 | 93.4 | 5.5 | 1.1 | 53.1e | ||
| TMP-SMX | >4 | >4 | ≤0.12 to >4 | 16.5 | 83.5 | 16.5 | 3.1 | 80.4 | |
| Colistin | 0.25 | >8 | ≤0.06 to >8 | 73.3 | 26.7 | 73.3 | 26.7 | ||
| K. pneumoniae (878) | |||||||||
| Aztreonam/avibactamb | 0.25 | 0.5 | ≤0.03 to >16 | (99.8)b | (99.8)b | ||||
| Ceftazidime/avibactam | 2 | >32 | ≤0.015 to >32 | 72.6 | 27.4 | 72.6 | 27.4 | ||
| Meropenem/vaborbactam | 2 | >32 | ≤0.015 to >32 | 60.4 | 2.9 | 36.8 | 63.2 | 36.8 | |
| Ceftolozane/tazobactam | >16 | >16 | ≤0.12 to >16 | 2.2 | 0.9 | 96.9 | 2.2 | 97.8 | |
| Aztreonam | >16 | >16 | ≤0.03 to >16 | 5.1 | 0.1 | 94.8 | 4.9 | 0.2 | 94.9 |
| Ciprofloxacin | >4 | >4 | ≤0.03 to >4 | 5.0 | 0.8 | 94.2 | 5.0 | 0.8 | 94.2 |
| Levofloxacin | 32 | >32 | 0.03 to >32 | 6.6 | 5.3 | 88.1 | 6.6 | 5.3 | 88.1 |
| Gentamicin | >16 | >16 | ≤0.12 to >16 | 43.5 | 3.0 | 53.5 | 41.3d | 58.7 | |
| Amikacin | 8 | >32 | 0.5 to >32 | 61.8 | 10.6 | 27.6 | 52.5d | 47.5 | |
| Minocycline | 4 | >32 | 0.5 to >32 | 56.9 | 17.3 | 25.8 | |||
| Tigecycline | 0.5 | 2 | 0.12 to >8 | 95.0 | 3.9 | 1.1 | 50.7e | ||
| TMP-SMX | >4 | >4 | ≤0.12 to >4 | 14.6 | 85.4 | 14.6 | 2.5 | 82.9 | |
| Colistin | 0.25 | >8 | ≤0.06 to >8 | 73.2 | 26.8 | 73.2 | 26.8 | ||
| E. cloacae complex (65) | |||||||||
| Aztreonam/avibactamb | 0.25 | 1 | ≤0.03 to >16 | (98.4)b | (98.4)b | ||||
| Ceftazidime/avibactam | >32 | >32 | 0.25 to >32 | 42.2 | 57.8 | 42.2 | 57.8 | ||
| Meropenem/vaborbactam | 4 | >32 | 0.03 to >32 | 57.8 | 10.9 | 31.2 | 68.8 | 31.2 | |
| Ceftolozane/tazobactam | >16 | >16 | 0.25 to >16 | 4.7 | 0.0 | 95.3 | 4.7 | 95.3 | |
| Aztreonam | >16 | >16 | 0.06 to >16 | 20.3 | 4.7 | 75.0 | 17.2 | 3.1 | 79.7 |
| Ciprofloxacin | 4 | >4 | ≤0.03 to >4 | 18.8 | 15.6 | 65.6 | 18.8 | 15.6 | 65.6 |
| Levofloxacin | 2 | 32 | 0.03 to >32 | 34.4 | 12.5 | 53.1 | 34.4 | 12.5 | 53.1 |
| Gentamicin | >16 | >16 | ≤0.12 to >16 | 31.2 | 14.1 | 54.7 | 31.2d | 68.8 | |
| Amikacin | 8 | >32 | 0.5 to >32 | 68.8 | 7.8 | 23.4 | 56.2d | 43.8 | |
| Minocycline | 4 | 32 | 0.5 to >32 | 70.3 | 6.2 | 23.4 | |||
| Tigecycline | 0.5 | 2 | 0.12 to 4 | 90.6 | 9.4 | 0.0 | 76.6e | ||
| TMP-SMX | >4 | >4 | ≤0.12 to >4 | 17.2 | 82.8 | 17.2 | 1.6 | 81.2 | |
| Colistin | 0.25 | >8 | 0.12 to >8 | 82.5 | 17.5 | 82.5 | 17.5 | ||
| E. coli (58) | |||||||||
| Aztreonam/avibactamb | 0.25 | 4 | ≤0.03 to >16 | (98.3)b | (98.3)b | ||||
| Ceftazidime/avibactam | >32 | >32 | ≤0.015 to >32 | 49.2 | 50.8 | 49.2 | 50.8 | ||
| Meropenem/vaborbactam | 8 | >32 | ≤0.015 to >32 | 47.5 | 8.5 | 44.1 | 55.9 | 44.1 | |
| Ceftolozane/tazobactam | >16 | >16 | ≤0.12 to >16 | 6.8 | 5.1 | 88.1 | 6.8 | 93.2 | |
| Aztreonam | >16 | >16 | 0.06 to >16 | 10.2 | 1.7 | 88.1 | 5.1 | 5.1 | 89.8 |
| Ciprofloxacin | >4 | >4 | ≤0.008 to >4 | 13.6 | 1.7 | 84.7 | 13.6 | 1.7 | 84.7 |
| Levofloxacin | 16 | >32 | ≤0.015 to >32 | 18.6 | 8.5 | 72.9 | 18.6 | 8.5 | 72.9 |
| Gentamicin | 2 | >16 | 0.5 to >16 | 57.6 | 0.0 | 42.4 | 54.2d | 45.8 | |
| Amikacin | 4 | >32 | 1 to >32 | 86.4 | 1.7 | 11.9 | 76.3d | 23.7 | |
| Minocycline | 2 | 32 | 0.5 to >32 | 72.9 | 5.1 | 22.0 | |||
| Tigecycline | 0.25 | 0.25 | ≤0.06 to 1 | 100.0 | 0.0 | 0.0 | 98.3 | 1.7 | |
| TMP-SMX | >4 | >4 | ≤0.12 to >4 | 18.6 | 81.4 | 18.6 | 0.0 | 81.4 | |
| Colistin | 0.25 | 0.25 | 0.12 to >8 | 98.3 | 1.7 | 98.3 | 1.7 | ||
| S. marcescens (36) | |||||||||
| Aztreonam/avibactamb | 0.25 | 1 | 0.12 to 2 | (100.0)b | (100.0)b | ||||
| Ceftazidime/avibactam | 1 | >32 | 0.12 to >32 | 88.9 | 11.1 | 88.9 | 11.1 | ||
| Meropenem/vaborbactam | 1 | 16 | 0.03 to >32 | 88.9 | 0.0 | 11.1 | 88.9 | 11.1 | |
| Ceftolozane/tazobactam | >16 | >16 | 0.5 to >16 | 11.1 | 5.6 | 83.3 | 11.1 | 88.9 | |
| Aztreonam | >16 | >16 | 0.06 to >16 | 16.7 | 2.8 | 80.6 | 16.7 | 0.0 | 83.3 |
| Ciprofloxacin | 4 | >4 | 0.03 to >4 | 13.9 | 8.3 | 77.8 | 13.9 | 8.3 | 77.8 |
| Levofloxacin | 2 | 32 | 0.06 to 32 | 13.9 | 25.0 | 61.1 | 13.9 | 25.0 | 61.1 |
| Gentamicin | 2 | >16 | 0.25 to >16 | 55.6 | 2.8 | 41.7 | 50.0b | 50.0 | |
| Amikacin | 16 | >32 | 1 to >32 | 72.2 | 11.1 | 16.7 | 44.4b | 55.6 | |
| Minocycline | 8 | 32 | 1 to >32 | 34.3 | 31.4 | 34.3 | |||
| Tigecycline | 2 | 4 | 0.5 to 8 | 55.6 | 41.7 | 2.8 | 5.6e | ||
| TMP-SMX | 4 | >4 | ≤0.12 to >4 | 38.9 | 61.1 | 38.9 | 22.2 | 38.9 | |
| Colistin | >8 | >8 | 0.25 to >8 | 16.7 | 83.3 | 16.7 | 83.3 | ||
TMP-SMX, trimethoprim/sulfamethoxazole.
b
Values in parentheses indicate percentage inhibited at ≤8 mg/L aztreonam/avibactam.
c
The vast majority (89.3%) of ceftolozane/tazobactam-susceptible isolates harboured a class D β-lactamase, mainly OXA-48-like (75.0%). Only two isolates had a class A carbapenemase: one KPC-2 and one IMI-4.
d
For infections originating from the urinary tract. For systemic infections, aminoglycosides must be used in combination with other active therapy.12
e
For comparison, EUCAST breakpoints published for E. coli and C. koseri (≤0.5 mg/L) were applied for all Enterobacterales species.12