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Competitive Transplants to Evaluate Hematopoietic Stem Cell Fitness
Published on: August 31, 2016
Influence of harvest bacterial contamination on autologous peripheral blood progenitor cells post-transplant
M J Majado1, A García-Hernández, A Morales
1Servicio de Hematologia, Hospital V. Arrixaca, Murcia, Spain. juliana.majado@carm.es
Abstract:
Microbiological contamination of manipulated blood products, including hematopoietic progenitors obtained from peripheral blood, is an infrequent but persistent problem in transplant units. The relevance of such contamination in causing patient infection has been reported as insignificant, but the effect on the post-transplant course has not been well documented. We studied the incidence of bacterial contamination in autologous peripheral blood progenitor cell transplants in two of the bench processing steps, as well as the repercussions in the post-transplant course affecting incidence of infections, transfusion requirements and time to engraftment. A total of 365 aphereses performed on 152 patients were cryopreserved in 617 bags. In 31 of these bags (5.0%), bacterial cultures were positive for Coagulase-negative Staphylococcus (31.1%), S. epidermidis (21.9%), Corynebacterium sp. (6.3%), S. warneri (6.3%), Stenotrophomonas maltophilia (6.3%), Streptococcus sp. (9.4%), Viridans group Streptococcus (3.1%) and more than one bacteria (Coagulase-negative Staphylococcus plus Corynebacterium) (15.6%). Half of the bags were contaminated at the time of freezing and the others at the time of thawing. The 31 contaminated bags were infused into 17 patients. In five of these the same contaminating bacteria was found. No difference between the two groups of patients (contaminated and non-contaminated) was found on the day the fever started, length of fever, blood transfusion requirements and engraftment, but length of hospitalization was significantly greater in patients receiving contaminated transplants.
Insights
Bacterial contamination in hematopoietic progenitor cell transplants occurred in 5.0% of bags, affecting hospitalization length but not patient infections or engraftment. This highlights the need for vigilance in transplant processing.
Area of Science:
- Hematology
- Microbiology
- Transplant Science
Background:
- Microbiological contamination of blood products, including hematopoietic progenitors, is a persistent issue in transplant settings.
- While patient infection risk from contaminated products is considered low, the impact on post-transplant outcomes is not well-documented.
Purpose of the Study:
- To investigate the incidence of bacterial contamination during autologous peripheral blood progenitor cell transplant processing.
- To evaluate the repercussions of this contamination on post-transplant infection rates, transfusion needs, and engraftment timelines.
Main Methods:
- Analysis of 365 aphereses from 152 patients, with 617 cryopreserved bags examined.
- Bacterial cultures were performed on bags at processing and thawing stages.
- Comparison of outcomes between patients receiving contaminated versus non-contaminated transplants.
Main Results:
- Bacterial contamination was detected in 5.0% (31/617) of cryopreserved bags.
- Common contaminants included Coagulase-negative Staphylococcus, S. epidermidis, and Corynebacterium sp.
- Patients receiving contaminated transplants had significantly longer hospitalizations but no differences in fever onset, fever duration, transfusion requirements, or engraftment.
Conclusions:
- Bacterial contamination of hematopoietic progenitor cell transplants is a significant concern, primarily impacting length of hospital stay.
- Current processing and thawing methods may introduce contaminants.
- Further strategies are needed to minimize contamination and its clinical impact in transplant recipients.
