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Risk factors for microbial contamination of peripheral blood stem cell products
Ayhan Donmez1, Sohret Aydemir, Bahar Arik
1Department of Hematology, Microbiology and Biostatistics, Ege University Medical School, Izmir, Turkey. ayhan.donmez@ege.edu.tr
Background:
Despite the well-known contamination rates and presence of microbial agents in stem cell products, the risk factors affecting microbial contamination have not been well described.
Study Design And Methods:
In a 12-year period, we retrospectively reviewed culture results of peripheral blood stem cell products with the intent of identifying risk factors for microbial contamination.
Results:
Microbial contamination was detected in 28 (5.7%) products of the postprocessing period and in 18 (3.66%) products of the postthawing period. Large-volume leukapheresis (LVL; odds ratio [OR], 5.85; 95% confidence interval [CI], 1.52-22.49; p = 0.01) and high numbers of stem cell culture sampling (OR, 1.4; 95% CI, 1.03-1.91; p = 0.03) were found to be risk factors for postprocessing bacterial contamination. The presence of postprocessing bacterial contamination was a risk factor for postthawing (OR, 28.89; 95% CI, 6.67-125.15; p < 0.001) and posttransplant (OR, 3.25; 95% CI, 1.24-8.50; p = 0.01) microbial growth. In transplants that were performed using contaminated products, the same pathogen was detected in 20% of patients and different pathogens were found in 35% of patients.
Conclusion:
Cultures should be carefully monitored in LVL products and in samples with high numbers of cultures performed. Growth of different bacterial pathogens must be considered in transplants that are performed with contaminated products.
Insights
Large-volume leukapheresis (LVL) and frequent stem cell cultures increase microbial contamination risk. Contaminated products can lead to pathogen transmission during transplantation.
Area of Science:
- Hematology
- Microbiology
- Transplantation Science
Background:
- Stem cell products are known to have microbial contamination.
- Risk factors for microbial contamination in stem cell products are not well-defined.
Purpose of the Study:
- To identify risk factors for microbial contamination in peripheral blood stem cell products.
Main Methods:
- Retrospective review of culture results over a 12-year period.
- Analysis of peripheral blood stem cell products.
Main Results:
- Microbial contamination occurred in 5.7% of postprocessing and 3.66% of postthawing products.
- Large-volume leukapheresis (LVL) and high stem cell culture sampling frequency were risk factors for postprocessing contamination.
- Postprocessing contamination significantly increased the risk of postthawing and posttransplant microbial growth.
Conclusions:
- Careful monitoring of cultures is essential for LVL products and samples with high culture numbers.
- Consider the potential for different bacterial pathogens when transplants use contaminated products.
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