Clinical impact and early prediction of carbapenem-resistant Pseudomonas aeruginosa bacteraemia in allogeneic hematopoietic stem cell transplantation recipients.

Objective: Although antipseudomonal agents are administered in high-risk patients, no reports have focused on the risk of carbapenem-resistant (CR) Pseudomonas aeruginosa bacteraemia in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients.

Methods: We retrospectively studied a cohort of adult allo-HSCT recipients with P. aeruginosa bacteraemia, focusing on a comparison between carbapenem-sensitive (CS) and CR P. aeruginosa after initiating conditioning chemotherapy at our institute between January 2005 and December 2020. The incidence, all-cause 30-d mortality of P. aeruginosa bacteraemia, and risk factors for carbapenem resistance among patients with P. aeruginosa bacteraemia in allo-HSCT recipients were evaluated.

Results: Forty-eight patients with P. aeruginosa bacteraemia were included, with an incidence of 3.84/100 recipients (CS = 1.92 vs. CR = 1.92). The all-cause 30-d mortality was significantly higher in CR P. aeruginosa bacteraemia (CS = 4.2% vs. CR = 39.1%; P = 0.003). The factor significantly associated with CR P. aeruginosa bacteraemia was carbapenem use for at least 3 d within 30 d before the onset of bacteraemia (odds ratio = 8.92; 95% confidence interval: 1.35-58.90). Inappropriate antimicrobial selection was significantly more frequent in CR P. aeruginosa bacteraemia (CS = 0% vs. CR = 29.2%; P ˂ 0.009).

Conclusion: Empirical combination therapy with reference to antimicrobial susceptibility profiles in each institution should be considered when CR P. aeruginosa bacteraemia is suspected in allo-HSCT recipients based on the risk of carbapenem exposure.