Bioburden of postmortem bone tissues with a procurement time exceeding 36 h

Area of Science:

• Biomedical Engineering
• Tissue Banking
• Microbiology

Background:

• Current bone procurement protocols mandate strict postmortem intervals (PMI) of 6 hours before cooling and tissue retrieval within 24-36 hours.
• Expanding procurement timelines could increase donor availability and allow more time for obtaining family consent.
• Concerns exist regarding potential microbiological contamination and biomechanical quality degradation with extended PMI.

Purpose of the Study:

• To evaluate the microbiological safety of bone tissue procured at extended postmortem intervals (PMI).
• To assess if extended PMI impacts bacterial load beyond acceptable limits for tissue banking.
• To determine the suitability of bone tissue for transplantation following delayed procurement.

Main Methods:

• Bone samples (iliac crest) were procured at 48-54 hours (Group 1) and 72-78 hours (Group 2) postmortem.
• Samples underwent mechanical preparation and chloroform treatment.
• Microbiological bioburden testing was performed after procurement, preparation, and treatment according to European Pharmacopoeia standards.
• Acceptance criterion: ≤ 9 × 10⁴ colony-forming units per gram (CFU/g).

Main Results:

• All tested bone samples, regardless of procurement time (up to 78 hours PMI), remained below the defined microbiological limit of 9 × 10⁴ CFU/g.
• The maximum observed bacterial load was 2.5 × 10² CFU/g.
• These bacterial levels are comparable to tissues procured within 24-36 hours under less stringent aseptic conditions.

Conclusions:

• Bone tissue procurement up to 78 hours postmortem does not lead to unacceptable microbiological contamination.
• Extended procurement times are viable for bone donation, potentially increasing tissue availability.
• The findings support the capacity of standard sterilization processes, like peracetic acid, to manage bacterial loads in delayed-procured bone grafts.