718. Activity of Ceftolozane–Tazobactam and Ceftazidime–Avibactam Against Clinical P. aeruginosa Isolates Collected in United States and Canada—SMART 2018
Bibliographic record
Abstract
Abstract Background Ceftolozane–tazobactam (C/T) is an antipseudomonal cephalosporin combined with a β-lactamase inhibitor. The combination was cleared by FDA and EMA and is approved in the United States and over 60 countries worldwide. Using clinical isolates collected in the United States and Canada as part of the global SMART surveillance program, we compared the activity of C/T and ceftazidime–avibactam (CAZ/AVI) against P. aeruginosa isolates and subsets nonsusceptible (NS) to selected antimicrobial agents. Methods In 2018, 31 clinical laboratories from United States and Canada collected up to 250 consecutive, aerobic or facultatively anaerobic, Gram-negative pathogens (GNP) from blood, intra-abdominal, urinary, and lower respiratory tract infections. A total of 6,178 GNP were collected, of which 1,138 (18.4%) were P. aeruginosa. MICs were determined using CLSI broth microdilution and interpreted with CLSI 2019 breakpoints. Results The MIC distributions of C/T and CAZ/AVI against 1,138 P. aeruginosa are shown below. The modal MIC value for C/T was ≥2 doubling dilutions lower than that for CAZ/AVI, and it was ≥3 dilutions lower than the C/T CLSI susceptible breakpoint, whereas the modal MIC value for CAZ/AVI was 2 dilutions lower than its susceptible breakpoint. Among all P. aeruginosa isolates, percentages of susceptibility were 96.0% (C/T), 93.8% (CAZ/AVI), 76.6% (CAZ and cefepime), 67.0% (imipenem [IMI]), 74.0% (meropenem [MEM]), 71.5% (piperacillin–tazobactam [TZP]), and 64.9% (aztreonam). Among subsets of nonsusceptible isolates, susceptibilities to C/T and CAZ/AVI were 83.5% and 74.4%, respectively (CAZ-NS subset, n = 266), 91.0% and 85.1% (IMI-NS, n = 376), 87.5% and 80.1% (MEM-NS, n = 296), 87.0% and 79.6% (TZP-NS, n = 324), and 72.4% and 57.8% among isolates nonsusceptible to all tested β-lactams (n = 116). Conclusion The activity of C/T exceeded that of CAZ/AVI and other tested comparators against a recent collection of clinical isolates of P. aeruginosa, including subsets of isolates nonsusceptible to other β-lactams. Susceptibilities to C/T were 6–14 percentage points higher than observed for CAZ/AVI among β-lactam-NS subsets. C/T promises to be an important treatment option for patients with antimicrobial-resistant P. aeruginosa infections. Disclosures All authors: No reported disclosures.
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) | 0.000 | 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".