Application of pulsed-field gel electrophoresis to identify the source of bacterial contamination of peripheral blood progenitor cell products

Sterility Testing for Hematopoietic Stem Cells

Over the last two decades, rapid technological advances have led to the wide adoption of cell and gene therapy products for the treatment of a variety of disease states. In this study, we reviewed the literature between 2003 and 2021 to provide a summary of overarching trends associated with microbial contamination in hematopoietic stem cells (HSCs) derived from peripheral blood, bone marrow, and cord blood. We provide a brief background on the regulatory context for human cells, tissues, and cellular and tissue-based products (HCT/Ps) as regulated by the US Food and Drug Administration (FDA), sterility testing expectations for autologous (Section 361) and allogeneic (Section 351) HSC products, and discuss clinical risks associated with the infusion of a contaminated HSC product. Finally, we discuss the expectations for current good tissue practices (cGTP) and current good manufacturing practices (cGMP) for the manufacturing and testing of HSC based on Section 361 and Section 351 categorization, respectively. We provide commentary on what is practiced in the field and discuss the critical need for updates to professional standards that keep pace with advancing technologies with an aim to clarify expectations for manufacturing and testing facilities to improve standardization across institutions.

Bacillus cereus septicemia attributed to a matched unrelated bone marrow transplant

BACKGROUND

Hematopoietic cell transplantation (HCT) is performed in more than 25,000 patients annually. Clinically significant bacterial transmission from HCT products is rare.

CASE REPORT

A 36-year-old male of Asian descent with chronic myelogenous leukemia developed sepsis leading to acute renal failure and disseminated intravascular coagulation during infusion of matched unrelated donor bone marrow. This product later tested positive for Bacillus cereus.

DISCUSSION

This HCT product traveled 31 hours at room temperature before arriving at the transplant center. Reducing transport times, transporting at 4 °C, and enhancing bacterial surveillance of HCT products may increase the ability to detect bacterial proliferation from transport.

CONCLUSION

To prevent a similar case in the future, we will begin Gram staining all HCT products in transit more than 24 hours to alert physicians of the need for prophylactic antibiotic therapy.

Quality monitoring of microbial contamination of cryopreserved parathyroid tissue

Cryopreservation of parathyroid tissue (PT) provides patients undergoing parathyroidectomy with an option for delayed autologous heterotopic parathyroid transplantation. A standard protocol for quality monitoring of PT has not been established. This article describes a method for detecting the presence of bacterial contamination in PT tissue intended for autologous transplantation. PT was received in the tissue bank, processed under aseptic conditions, and placed into cryopreservation medium. Sterility testing was performed at 2 time points prior to cryopreservation. From January 2005 to October 2008, 47 PT samples were cryopreserved. The following bacteria were isolated from 11 PT specimens: Staphylococcus epidermidis, Staphylococcus capitis subspecies ureolyticus, Staphylococcus lugdunensis, Bacillus pumilus, and corynebacteria (diphtheroids). 23% of PTs were contaminated at the time of collection, predominantly with indigenous bacteria. Quality monitoring using this protocol is a useful tool to identify tissues contaminated with bacteria.