# Ceftazidime–Avibactam Resistance in Carbapenem-Resistant Klebsiella pneumoniae Bloodstream Infections: Risk Factors and Clinical Outcomes

## TL;DR

This study examines risk factors for ceftazidime–avibactam resistance in Klebsiella pneumoniae bloodstream infections and its impact on patient outcomes.

## Contribution

The study identifies clinical risk factors and outcomes associated with CAZ-AVI resistance in CRKP bacteremia.

## Key findings

- 42.8% of patients had CAZ-AVI-resistant CRKP strains.
- Resistant infections were linked to longer hospital stays and higher comorbidity scores.
- Pitt bacteremia score and creatinine levels predicted 30-day mortality.

## Abstract

Background/Introduction: Carbapenem-resistant Klebsiella pneumoniae (CRKP) bacteremia is a serious public health problem due to its high mortality rate and limited treatment options. This study aimed to identify risk factors associated with ceftazidime–avibactam (CAZ-AVI) resistance in CRKP bacteremia and to evaluate its impact on clinical outcomes. Methods: This retrospective single-center cohort study included adult patients with CRKP bloodstream infections treated at a tertiary hospital in Türkiye between January 2021 and December 2024. Demographic, clinical, and laboratory data were collected, and risk factors for CAZ-AVI resistance and 30-day mortality were analyzed. Results: Among 154 patients, 42.8% had CAZ-AVI-resistant strains. Resistant infections were associated with longer hospital stays and higher Charlson Comorbidity Index (CCI) scores. The resistance rate was lower in patients with intra-abdominal infections, while fluoroquinolone and fosfomycin use was more common in the resistant group. The overall 30-day mortality rate was 57%. Pitt bacteremia score and creatinine levels were identified as independent predictors of mortality. Discussion: CAZ-AVI resistance in CRKP bacteremia appears to develop in patients with prolonged hospitalization and high comorbidity burden. These factors likely increase exposure to resistant microorganisms and antibiotic pressure, complicating treatment outcomes. Conclusions: CAZ-AVI resistance in CRKP bacteremia is associated with specific clinical risk profiles and contributes to high mortality. Identifying high-risk patients and optimizing antimicrobial stewardship are essential to improve prognosis.