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Published on: June 5, 2012
Rate of growth of Pseudomonas fluorescens in donated blood
A P Gibb1, K M Martin, G A Davidson
1Department of Medical Microbiology, University Medical School, Edinburgh.
Aims:
To examine how delayed refrigeration of blood affects the growth of Pseudomonas fluorescens, one of the two most important causes of sepsis resulting from transfusion of contaminated blood.
Methods:
Two donations of whole blood were each divided into three aliquots and inoculated with 5-10 cfu/ml of a P fluorescens strain from a case of transfusion associated sepsis. From each donation, one aliquot was placed at 4 degrees C, one was held at 20 degrees C for six hours prior to refrigeration and the third was held at 20 degrees C for 24 hours prior to refrigeration. Samples were aseptically withdrawn over 17 days and bacterial counts were determined using a pour plate technique.
Results:
The rate of growth of P fluorescens in blood at 20 degrees C was increased compared with blood at 4 degrees C. At 24 hours the aliquots held at 20 degrees C for six and 24 hours had, respectively, 174 and 29,000 cfu/ml compared with 15 cfu/ml in aliquots held at 4 degrees C. There was no evidence of increased killing of P fluorescens at the higher temperature.
Conclusions:
These results suggest that blood for transfusion should be refrigerated as soon as possible after collection.
Insights
Delayed refrigeration of blood significantly increases the growth of Pseudomonas fluorescens, a cause of transfusion-associated sepsis. Prompt refrigeration of blood donations is crucial to prevent bacterial proliferation and ensure transfusion safety.
Area of Science:
- Transfusion Medicine
- Microbiology
- Blood Safety
Background:
- Pseudomonas fluorescens is a significant cause of transfusion-associated sepsis.
- Timely refrigeration of blood is critical for preventing bacterial contamination and growth.
Purpose of the Study:
- To investigate the impact of delayed refrigeration on Pseudomonas fluorescens growth in whole blood.
- To assess the implications for blood transfusion safety.
Main Methods:
- Whole blood aliquots were inoculated with P. fluorescens.
- Samples were stored at 4°C or at 20°C for 6 or 24 hours before refrigeration.
- Bacterial counts were determined over 17 days using pour plate techniques.
Main Results:
- P. fluorescens exhibited increased growth rates at 20°C compared to 4°C.
- After 24 hours, bacterial counts were significantly higher in blood held at 20°C (174 and 29,000 cfu/ml) versus 4°C (15 cfu/ml).
- No enhanced bacterial killing was observed at the higher temperature.
Conclusions:
- Delayed refrigeration promotes P. fluorescens proliferation in stored blood.
- Immediate refrigeration of collected blood is recommended to minimize the risk of transfusion-related sepsis.
