Table 3.
In Vitro Activity of Sulbactam-durlobactam Against Phenotypically Antibiotic-Nonsusceptible Acinetobacter baumannii–calcoaceticus Complex Clinical Isolates Collected Globally From 2016 to 2021
| Resistance Phenotypea | No. | Sulbactam-durlobactam | ||
|---|---|---|---|---|
| MIC50, µg/mL | MIC90, µg/mL | % Susceptibleb | ||
| All isolates | 5032 | 1 | 2 | 98.3 |
| Sulbactam nonsusceptible | 2670 | 1 | 4 | 96.9 |
| Imipenem nonsusceptible | 2570 | 1 | 4 | 96.7 |
| Colistin resistant | 204 | 2 | 4 | 98.0 |
| Ciprofloxacin nonsusceptible | 2796 | 1 | 4 | 97.5 |
| Amikacin nonsusceptible | 2083 | 2 | 4 | 96.9 |
| Minocycline nonsusceptible | 1092 | 2 | 4 | 97.7 |
| Multidrug-resistantc | 2680 | 1 | 4 | 96.9 |
| Extensively drug-resistantc | 2116 | 2 | 4 | 97.2 |
Source: [35].
Abbreviations: MIC50, The antibiotic concentration that inhibits the growth of 50% of the tested isolates; MIC90, The antibiotic concentration that inhibits the growth of 50% of the tested isolates.
Nonsusceptibility or resistance as determined by Clinical and Laboratory Standards Institute M100 (2021) [39].
Sulbactam and sulbactam-durlobactam MICs were interpreted using the preliminary breakpoint of susceptible ≤4 µg/mL.
Multidrug-resistant isolates were defined as nonsusceptible to 1 agent from ≥3 different antimicrobial classes and extensively drug-resistant isolates were defined as not susceptible to at least 5 of the following 7 agents (classes): cefepime (extended-spectrum cephalosporins), imipenem (carbapenems), amikacin (aminoglycosides), ciprofloxacin (fluoroquinolones), minocycline (tetracyclines), sulbactam (penicillin/β-lactamase inhibitor; sulbactam is the active component of ampicillin-sulbactam against Acinetobacter spp), and colistin (polymyxins), based on proposed international guidelines [40]. For colistin, only colistin-resistant isolates were used in these determinations as only intermediate and resistant interpretive criteria exist for colistin [39].