The Epidemiology of Multidrug-Resistant Pathogens in Hematopoietic Stem Cell Transplantation (HSCT) Patients: A Five-Year Retrospective Study at a Cancer Center

Multidrug-resistant (MDR) pathogens present a significant threat to hematopoietic stem cell transplant (HSCT) recipients; despite their critical implications, regional data on their infection patterns remain scarce. This study aimed to characterize the incidence, pathogen and antimicrobial resistance distribution of clinically confirmed bacterial infections among HSCT recipients. A retrospective analysis was conducted at King Hussein Cancer Center, Jordan (2018–2022). MDR pathogens were defined per CDC criteria. During the study period, 1157 HSCT procedures were performed. A total of 327 patients developed clinically documented bacterial infections, yielding an overall cumulative incidence of 28.3%, with a higher burden in the pediatric cohort (34.7%), including exclusive identification of Klebsiella oxytoca in pediatrics (2.3%). Gram-negative bacteria dominated, with Escherichia coli (50.5%) and Klebsiella pneumoniae (22.0%) being most common. Extended-spectrum beta-lactamase (ESBL) production was the dominant resistance mechanism (71.3%), followed by carbapenem-resistant Enterobacteriaceae (CRE; 14.1%), methicillin-resistant Staphylococcus aureus (MRSA; 8.6%), and carbapenem-resistant Pseudomonas aeruginosa (CRPA; 7.0%). The urogenital (39.1%) and bloodstream (31.2%) were the most infected sites. Significant site-specific associations were noted for ESBL production, MDR-Acinetobacter baumannii (p < 0.001) and MRSA (p = 0.007). Temporal analysis revealed a convergent MDR peak in 2021. Our findings offer critical insights into MDR pathogen incidence in HSCT recipients in the Middle East, informing improved infection management and intensified antimicrobial stewardship in this high-risk population.