Bacterial survival in radiopharmaceutical solutions: a critical impact on current practices

Abstract

Background: The aim of this brief communication is to highlight the potential bacteriological risk linked to the processes control of radiopharmaceutical preparations made in a radiopharmacy laboratory. Survival rate of Pseudomonas aeruginosa (ATCC: 27853) or Staphylococcus aureus (ATCC: 25923) or Staphylococcus epidermidis (ATCC: 1228) in multidose technetium-99 m solution was studied.

Results: Depending on the nature and level of contamination by pathogenic bacteria, the lethal effect of radioactivity is not systematically observed. We found that P. aeruginosa was indeed affected by radioactivity. However, this was not the case for S. epidermidis, as the quantity of bacteria found in both solutions (radioactive and non-radioactive) was rapidly reduced, probably due to a lack of nutrients. Finally, the example of S. aureus is an intermediate case where we observed that high radioactivity affected the bacteria, as did the absence of nutrients in the reaction medium. The results were discussed in the light of current practices on the sterility test method, which recommends waiting for radioactivity to decay before carrying out the sterility test.

Conclusion: In terms of patient safety, the results run counter to current practice and the latest EANM recommendation of 2021 that radiopharmaceutical preparations should be decayed before sterility testing.

Fig. 1

Bacterial survival rate in technetium-99 m radioactive solutions. The survival rate of a Pseudomonas aeruginosa ATCC: 27853 or b Staphylococcus aureus ATCC: 25923) or c Staphylococcus epidermidis ATCC: 1228 was followed over time (0 to 8 h) in technetium-99 m radioactive solutions at 1.85 to 11.1 GBq (green circle) and non-radioactive technetium-99 solutions (red square). For each incubation time in a radioactive solution, the results are expressed as a percentage of the mean survival rate in relation to the initial bacterial charge load. The asterisk (*) represents the p-value of the Dunnett statistical test. One, two and three asterisks means that the p-value is respectively less than 0.05, 0.001 and 0.0001