Pancreas preservation fluid microbial contamination is associated with poor islet isolation outcomes - a multi-centre...

Area of Science:

• Transplantation immunology
• Microbiology
• Cell therapy

Background:

• Microbiological safety of islet preparations is critical for successful transplantation.
• Preservation medium contamination is a frequent issue in islet isolation.
• The impact of contamination on islet yield and function is not fully understood.

Purpose of the Study:

• To analyze the prevalence of microbial contamination in islet preservation medium.
• To correlate microbial contamination with islet isolation and transplantation outcomes.
• To evaluate strategies for mitigating the risk of transplanting contaminated islet preparations.

Main Methods:

• Analysis of microbiological samples from islet isolations (2006-2016).
• Correlation of contamination data with islet yield, purity, and transplant outcomes.
• Assessment of the impact of an additional 24-hour islet culture sampling protocol.

Main Results:

• 64.4% of donor pancreases showed preservation medium contamination, with Staphylococcus, Streptococcus, and Candida species being prevalent.
• Contamination was associated with longer ischemia times, lower islet yield, purity, transplant rate, and in vitro function.
• Despite contamination in 6% of preparations, insulin independence rates were unaffected; however, 6 patients received contaminated islets.
• Implementing a 24-hour culture sampling reduced the risk of transplanting contaminated islets by 50%.

Conclusions:

• Pancreas preservation fluid contamination negatively impacts islet transplant rates and in vitro function but not graft survival.
• Routine microbiological testing 1 day post-isolation is crucial to prevent the transplantation of contaminated islet preparations.