Epidemiology, treatment and outcomes of antimicrobial-resistant infections in hematopoietic stem cell transplant recipients

PURPOSE OF REVIEW: To provide an overview of the current epidemiology of resistant bacterial infections in hematopoietic cell transplant (HCT) recipients, evaluate recent outcome data, and discuss available treatment strategies in this population. RECENT FINDINGS: Recent studies report an increasing incidence of infections caused by multidrug-resistant bacteria among HCT recipients, with marked geographical variability and a significant impact on morbidity and mortality. Several novel agents, including new β-lactam/β-lactamase inhibitors and cefiderocol, have expanded treatment options for resistant Gram-negative infections. However, most evidence supporting their efficacy derives from studies conducted in the general population, as immunocompromised and HCT patients are frequently underrepresented in clinical trials. SUMMARY: In recent years, growing real-world and observational data have become available specifically in immunocompromised patients, supporting treatment approaches largely consistent with those recommended for the general population, while highlighting important clinical considerations, such as empirical therapy in patients at risk for resistant infections. Ceftolozane-tazobactam is a preferred option for difficult-to-treat Pseudomonas aeruginosa , with combination therapy reserved for selected severe cases. Cefiderocol should be considered in specific scenarios, particularly infections caused by susceptible metallo-β-lactamase-producing organisms. For resistant Gram-positive infections, optimized daptomycin dosing is recommended. Antimicrobial stewardship strategies, including de-escalation and shorter treatment courses for Gram-negative bloodstream infections, are essential to preserve the efficacy of novel agents.