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Contamination during in vitro processing of bone marrow for transplantation: clinical significance
H M Lazarus1, M Magalhaes-Silverman, R M Fox
1University Ireland Cancer Center, Cleveland.
Abstract:
We determined the prevalence and clinical significance of positive microbiologic cultures obtained from 194 consecutive bone marrow harvests intended for infusion in 188 consecutive adult bone marrow transplant patients. Microbiologic cultures were obtained at harvest, after manipulation in vitro (for ABO imcompatibility or purging procedures), and at the time of thawing and infusion (after earlier cryopreservation). Only one of 194 marrow harvests was culture-positive intra-operatively (from an ABO-compatible allogeneic marrow that was infused without manipulation). None of 39 other allogeneic marrows (including 21 ABO-incompatible marrows which were manipulated in vitro) and none of 154 autologous marrows (including 40 which were purged in vitro) grew bacteria or fungi. On the other hand, 12 of 153 (8%) bone marrow samples were positive for micro-organisms after thawing at the time of infusion. The predominant organisms cultured were gram negative bacilli (including five Pseudomonas sp.), probably introduced during the thawing process in a water bath. In only one of 13 contaminated marrows was the same organism(s) (Pseudomonas picketti and Pseudomonas paucimobilis) recovered in vivo during the transplant course. This patient experienced a bacteremia which was eradicated without sequelae. Contamination of marrow can occur during the procurement and in vitro handling processes. With proper sterile technique bone marrow infusion does not pose a significant infectious risk for the immunocompromised transplant patient.
Insights
Microbiologic cultures revealed low contamination rates in bone marrow harvests. However, 8% of bone marrow samples showed microbial growth post-thaw, primarily gram-negative bacilli, highlighting the importance of sterile thawing techniques in bone marrow transplantation.
Area of Science:
- Hematology
- Microbiology
- Transplantation Immunology
Background:
- Bone marrow transplantation is a critical treatment for various hematologic malignancies and other diseases.
- Maintaining the sterility of bone marrow grafts is essential to prevent infectious complications in immunocompromised patients.
Purpose of the Study:
- To determine the prevalence and clinical significance of positive microbiologic cultures in bone marrow harvests.
- To identify potential sources of microbial contamination during bone marrow processing and infusion.
Main Methods:
- Prospective study of 194 bone marrow harvests from 188 adult bone marrow transplant patients.
- Microbiologic cultures were performed at harvest, after in vitro manipulation, and post-thaw before infusion.
- Organisms were identified, and clinical outcomes were monitored.
Main Results:
- Only one of 194 harvests was culture-positive intra-operatively.
- No bacterial or fungal growth was observed in manipulated allogeneic or autologous marrows.
- Post-thaw cultures revealed contamination in 8% (12/153) of samples, predominantly with gram-negative bacilli, likely from water bath thawing.
- Only one patient with contaminated marrow developed bacteremia, which was successfully treated.
Conclusions:
- Bone marrow harvests are generally sterile at procurement and after in vitro manipulation.
- The thawing process represents a significant risk for microbial contamination of bone marrow grafts.
- Adherence to sterile techniques during bone marrow processing and infusion minimizes infectious risks for transplant recipients.