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

To evaluate clinical impact of ceftazidime/avibactam on treating infections due to MDR Gram-negative bacteria in patients with haematological malignancies (HMs). 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. 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. Our study provides further evidence about the effectiveness of ceftazidime/avibactam in treating infections in patients with HMs.