The actual usefulness of culturing apheresis products in hematopoietic stem cell autotransplants.

BACKGROUND

Bacterial cultures of apheresis products are mandated by FACT-JACIE standards as a safety measure in autologous hematopoietic stem cell transplantation (aHSCT). However, results are often available only after reinfusion, raising questions about their clinical utility, particularly in programs that use fresh, non-cryopreserved products.

OBJECTIVE

To evaluate the incidence, microbiological profile, and clinical relevance of positive bacterial cultures in apheresis products used for aHSCT in autoimmune diseases.

METHODS

This prospective study included 629 apheresis products administered to 586 patients with MS or CIDP who underwent outpatient, non-cryopreserved aHSCT between July 2021 and March 2025. Bacterial cultures were performed from product aliquots using the BACTEC system (aerobic and anaerobic bottles). Positive isolates underwent antibiotic susceptibility testing. Culture results, timing of positivity, and 28-day post-infusion outcomes were analyzed.

RESULTS

Bacterial contamination was detected in 8 of 629 products (1.3 %). In one case, Escherichia coli was isolated within 24 h, leading to identification of a urinary tract infection and fatal sepsis in the patient; the contaminated product was discarded. The remaining seven cases became positive after 2-11 days (median: 6), when products had already been infused. Isolates included Cutibacterium acnes (n = 6), Staphylococcus capitis (n = 1), and Coryneform bacteria (n = 1). All were considered contamination during aliquot handling. No clinical complications occurred in these patients during the 28-day follow-up.

CONCLUSION

Routine bacterial cultures of apheresis products yielded clinically relevant information in only 1 of 629 procedures. Most positive results reflected contamination of aliquots rather than true product infection, suggesting that the value of routine cultures in fresh aHSCT for autoimmune diseases may be limited and warrants re-evaluation.