P-1323. Ceftazidime–avibactam in real-world clinical practice: results from a single center

TL;DR

This study evaluates ceftazidime–avibactam's real-world effectiveness against multidrug-resistant Gram-negative infections, finding it effective but highlighting high mortality risks.

Contribution

The study provides real-world clinical data on ceftazidime–avibactam's use against MDR Gram-negative infections, including mortality risk factors.

Findings

Ceftazidime–avibactam with aztreonam is effective against MDR Gram-negative pathogens, including MBL-resistant strains.

ICU admission, high INCREMENT scores, and urinary catheter use are independently linked to higher mortality in these infections.

Abstract

Over the past decade, rising multidrug resistance (MDR) in Gram-negative bacteria has become a global health emergency and clinical challenge. This study examines clinical features, resistance patterns, antibiotic therapy, and mortality outcomes.

We conducted a retrospective, single-center study (Nov 2019–Sept 2024) on hospitalized patients who received ceftazidime–avibactam (±aztreonam) for ≥72 hours. Data included demographics, comorbidities, prior healthcare exposures, clinical severity scores, microbiology, antibiotic regimens, treatment adjustments, and outcomes.

A total of 109 patients were included (62% male, median age 49 [range 16–88]), with a median hospital stay of 31 days (range 4–248). Severe clinical scores were noted in 19% (PITT ≥4), 32% (CCI ≥4), and 38% (INCREMENT ≥8). Central venous catheters were used in 75%, prior antibiotic use in 66%, prior hospitalization in 58%, and urinary catheters in 49%. Hematologic malignancies were present in 35%, mainly acute myeloid leukemia (17%). Klebsiella pneumoniae was the predominant pathogen (66%), often isolated alone. Multidrug resistance was common (MBL in 22%, MBL+ESBL in 37%). All patients received empiric antibiotics (median 3 days), most frequently ceftazidime-avibactam with aztreonam (39%). Targeted therapy (median 7 days) was used in 77%, commonly the same regimen (48%). Antibiotic regimens were changed in 77% (escalation 57%, de-escalation 17%). Clinical cure was achieved in 74%, but mortality was 33% (16% infection-related). ICU admission (OR 4.1, p=0.034), INCREMENT ≥8 (OR 3.5, p=0.035), and urinary catheter use (OR 4.6, p=0.025) were independently associated with mortality.

This study highlights the importance of early, targeted antibiotics and comprehensive management for multidrug-resistant (MDR) Gram-negative infections. Ceftazidime–avibactam, particularly with aztreonam, is effective against MDR pathogens, including MBL-resistant strains. ICU admission, high INCREMENT scores, and urinary catheter use are linked to higher mortality, stressing the need for vigilant risk assessment and tailored therapy. These findings offer real-world guidance for clinical decisions in this challenging setting.

Jon Salmanton-Garcia, MSc, MPH, PhD, menarini, gilead, astrazeneca, pfizer: Honoraria