Clinical impact of ceftazidime/avibactam on the treatment of suspected or proven infections in a large cohort of patients with haematological malignancies: a multicentre observational real-world study

objectives: to evaluate clinical impact of ceftazidime/avibactam on treating infections due to MDR gram-negative bacteria in patients with haematological malignancies (HMs). methods: we conducted a retrospective, observational study at 17 Italian haematological wards that included patients with HMs receiving ceftazidime/avibactam for the treatment of suspected or proven infections. the primary endpoint was all-cause mortality 30 days after infection onset. secondary endpoints included the development of in vitro ceftazidime/avibactam resistance, adverse reactions and infection relapse. results: of 198 patients enrolled, 66 had fever of unknown origin and 132 had microbiologically proven infections (MPIs). enterobacterales were responsible for 98 MPIs, with KPC producers accounting for 75% of these, and carbapenem-resistant pseudomonas aeruginosa caused 25% of MPIs. the overall 30-day mortality rate was 17.7%. Infection relapse occurred in four patients with MPI. patients who died within 30 days of infection onset tended to have pre-existing cerebrovascular diseases, a charlson comorbidity Index > 4 and septic shock at infection onset and had received inadequate initial antibiotic therapy. thirty-day mortality was independently associated with septic shock at infection onset and inappropriate initial antibiotic therapy. conclusions: our study provides further evidence about the effectiveness of ceftazidime/avibactam in treating infections in patients with HMs.