2149. <i>In vitro</i> Activity of Aztreonam-avibactam and Comparator Agents Against Carbapenem-Resistant Enterobacterales With and Without Carbapenemases, ATLAS Global Surveillance Program, 2017–2021
Bibliographic record
Abstract
Abstract Background The investigational β-lactam/non-β-lactam β-lactamase inhibitor combination aztreonam-avibactam (ATM-AVI) is active in vitro against CRE isolates, including MBL-producers, as well as those co-producing serine β-lactamases of Class A, C, and some class D types. This study evaluated the in vitro activity of ATM-AVI and comparators against carbapenemase- and non-carbapenemase-producing CRE collected globally from 2017−2021 as part of the ATLAS surveillance program. Methods 85,990 non-duplicate, clinically relevant Enterobacterales isolates were collected from 258 medical centers located in 56 countries worldwide (excluding N. America and China). Susceptibility testing was performed by CLSI broth microdilution and interpreted using CLSI 2023 breakpoints. ATM-AVI was tested at a fixed concentration of 4 mg/L avibactam. A tentative ATM-AVI pharmacokinetic/pharmacodynamic (PK/PD) susceptible MIC breakpoint of ≤ 8 mg/L was applied for comparison purposes. Organisms with meropenem MIC &gt;1 mg/L and Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis with aztreonam or ceftazidime MIC &gt;1 mg/L were screened for β-lactamase genes by PCR and Sanger sequencing. Results In total, 5,473 isolates were identified as CRE based on resistance to meropenem. ATM-AVI demonstrated potent in vitro activity against the CRE, with 99.3% of isolates (MIC90, 1 mg/L) inhibited at ≤8 mg/L (Table). ATM-AVI inhibited 99.5% of the carbapenemase-positive CRE, including 99.1% of the MBL-carriers (n=2,375) and 99.8% of serine-carbapenemase carriers (n=2,675) at ≤8 mg/L. Activity was somewhat reduced against the 441 CRE without detected carbapenemases as 96.3% (MIC90, 4 mg/L) of the isolates were inhibited at ≤8 mg/L aztreonam-avibactam. Amikacin was the most active comparator, although &lt; 50% of each subgroup was susceptible at the CLSI breakpoint. Conclusion Based on MIC90 values and the preliminary PK/PD breakpoint, ATM-AVI demonstrated potent in vitro activity against CRE, including MBL- and serine carbapenemase-carrying isolates. As limited therapeutic options presently exist for treating infections caused by CRE, further development of this agent appears warranted. Disclosures Mark G Wise, PhD, Merck & Co., Inc.: Honoraria|Pfizer Inc.: Honoraria|Venatorx: Paid fees for conducting the study and abstract preparation Daniel F. Sahm, PhD, Merck & Co., Inc.: Honoraria|Pfizer Inc.: Honoraria|Venatorx: Paid fees for conducting the study and abstract preparation
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".