Infectious Complications in Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) creates a profound immunocompromised state that predisposes recipients to a spectrum of infectious complications. In the pre-engraftment phase, profound neutropenia and mucosal barrier injury favour translocation of gut flora, leading to bloodstream infections (BSIs) and febrile neutropenia. Central venous catheter use further increases the risk of catheter-related BSIs. During early and late post-engraftment, the balance between immune reconstitution and graft-versus-host disease prophylaxis dictates susceptibility to viral reactivations, invasive fungal disease and opportunistic bacterial pathogens. The epidemiology of bacterial BSIs has shifted in many centres from predominantly Gram-positive cocci to Gram-negative rods and multidrug-resistant organisms (MDROs), driven by widespread antibiotic prophylaxis and local resistance patterns. Viral complications such as cytomegalovirus and Epstein–Barr virus remain significant, while mould infections from Aspergillus species are a leading cause of non-bacterial morbidity. Effective management relies on early risk stratification, tailored empirical antimicrobial regimens informed by colonisation surveillance and local antibiograms, and non-pharmacological measures including stringent infection control and antimicrobial stewardship. Despite advances in diagnostic techniques and supportive care, infectious complications remain a principal determinant of transplant outcome, underscoring the need for integrated clinical, microbiological and genomic surveillance to guide personalised prevention and treatment strategies.

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Infectious Complications in Hematopoietic Stem Cell Transplantation publication trend

The graph below shows the total number of articles in infectious complications in hematopoietic stem cell transplantation across all publications each year (not limited to Nature Index journals).

Technical terms

Neutropenia: A marked reduction in circulating neutrophils that impairs innate defence against bacteria and fungi.

Mucosal Barrier Injury: Damage to the gastrointestinal lining, often due to conditioning regimens, which permits microbial translocation into the bloodstream.

Bloodstream Infection (BSI): Presence of viable pathogens in the blood, commonly resulting in systemic inflammatory response and sepsis.

Multidrug-Resistant Organism (MDRO): A pathogen resistant to at least three classes of antimicrobial agents, complicating empirical therapy.

Allogeneic Transplantation: Transfer of hematopoietic stem cells from a genetically different donor, requiring graft-versus-host disease prophylaxis and posing distinct infection risks.

References

1. Clinical and genomic characterization of carbapenem-resistant Enterobacterales bloodstream infections in patients with hematologic malignancies. Frontiers in Cellular and Infection Microbiology (2024).
2. Development of a Clinical Score to Stratify the Risk for Carbapenem-Resistant Enterobacterales Bacteremia in Patients with Cancer and Hematopoietic Stem Cell Transplantation. Antibiotics (2023).
3. Bacterial Bloodstream Infections after Allogeneic Hematopoietic Stem Cell Transplantation: Etiology, Risk Factors and Outcome in a Single-Center Study. Microorganisms (2023).