Determination of the degree of bacterial contamination of whole-blood collections using an automated microbe-detection system.
BACKGROUND
The prevalence of bacterial contamination in whole-blood collections, either with immediate sampling or sampling after overnight storage as whole blood at 20 degrees C, is determined.


METHODS
Whole blood was collected under blood bank conditions in special five-bag systems, allowing sampling in a closed system for culture bottles. Samples were taken within 2 hours after collection (Group 1) or after overnight storage of the whole blood at 20 degrees C (Group 2). Culture bottles were incubated for 7 days, and positive samples were entered on agar plates for confirmation and determination.


RESULTS
In Group 1, 9219 units were tested; 27 units were positive with positive subculture, that is, 0.29 percent with a 95% CI of 0.19 to 0.42 percent. In Group 2, 9038 units were tested; 36 units were positive with positive subculture, that is, 0.39 percent with a 95% CI of 0.28 to 0.55 percent. No significant difference could be found between the two test groups. The majority of bacteria were either Staphylococcus (all coagulase-negative) or Propionibacterium species.


CONCLUSIONS
For a total of 18,257 units, 0.34 percent (CI, 0.25-0.44) of whole-blood collections appeared to have bacterial contamination (mainly skin-derived). Overnight storage of whole blood at 20 degrees C did not have a significant effect on the prevalence of bacterial contamination.
de Korte
D
D
CLB and the De Meierij Blood Bank, Sanquin Blood Supply Foundation, Amsterdam, the Netherlands. D_de_Korte@CLB.nl
Marcelis
J H
JH
Soeterboek
A M
AM
D001419:Bacteria / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000517:prevention & control* / Q000635:transmission*; D001431:Bacteriological Techniques / Q000295:instrumentation; D001800:Blood Specimen Collection / Q000592:standards*; D006801:Humans; D065227:Transfusion Reaction