Susceptibility of Ceftazidime-avibactam in bloodstream infections caused by multidrug-resistant Enterobacterales and Pseudomonas aeruginosa

ABSTRACT Background and objectives Ceftazidime-Avibactam (CAZ-AVI) is one of the last options to treat Enterobacteriales and Pseudomonas aeruginosa carbapenem-resistant. We aim to describe the susceptibility profile of bloodstream isolates of Enterobacterales and Pseudomonas aerunosa to ceftazidime-avibactam (CAZ-AVI) among strains resistant to third- and fourth-generation cephalosporins and/or carbapenems. Methods We conducted a retrospective descriptive study in two pediatric hospitals of Rio de Janeiro city, Brazil, between January 2023 and February 2025. All blood samples with resistance to third/fourth cephalosporins and/or carbapenem resistance were tested to CAZ-AVI, according to the BRCast methodology. Sensibility of CAZ-AVI and clinical profile of patients and outcomes were described. Results We analyzed 116 blood samples. Of these, 107/116 (92.2%) were resistant to third/fourth-generation cephalosporins with susceptibility to carbapenems, and 9/116 (7.8%) were resistant to both third/fourth-generation cephalosporins and carbapenems. Overall susceptibility to CAZ-AVI was 107/116 (92.2%). The 116 blood samples represented 73 bloodstream infections (BSI) in 66 patients, including 66 single episodes and 7 persistent BSIs. Of the 73 infections, 69(94.5%) were caused by Enterobacterales and 4 (5.5%) by Pseudomonas aeruginosa . Twenty-two (30.1%) infections were detected at hospital admission, and 51 (69.9%) were healthcare-associated infections. Death occurred in 5/73 (6.8%) patients. Length of hospital stay (p=0.01596) were statistically significantly higher in non-survivors compared to survivors. The CAZ-AVI was prescribed for four patients with Enterobacteriales or Pseudomonas aeruginosa infections with clearance from the blood. Conclusion Susceptibility of CAZ-AVI to BSI in children was higher and this antibiotic could be an option to treat carbapenem-resistant infection due to Enterobacteriales and Pseudomonas aeruginosa .