Rapid, sensitive detection of bacteria in platelet samples with Fountain Flow Cytometry.
BACKGROUND
There is a current need to develop a technique for bacterial screening of platelet donations that is more rapid, sensitive, and economical than alternatives. The objective of this research was to perform a pilot test of the viability of Fountain Flow Cytometry (FFC), for the rapid and sensitive detection of bacteria in platelet donations.


METHODS
Platelet samples were inoculated with serial dilutions of five selected bacterial strains. Samples were then centrifuged, reconstituted in buffer, and stained with a live/dead bacterial stain cocktail. The resulting aqueous sample was measured by FFC, in which the sample passed as a stream in front of an LED, which excited the fluorescent labels. Fluorescence was detected with a digital camera as the sample flowed toward it.


RESULTS
Fountain Flow Cytometry enumeration yielded results that were linear with bacterial concentration, having an R2of ≥0.98 with a detection efficiency of 92%±3%. Measurements of uninoculated samples showed a false-positive detection rate at ~400 colony forming units (CFU)/mL. Detection of bacterial concentrations in platelets above this threshold can be made in ~15 minutes, including sample preparation time.


CONCLUSIONS
This pilot study supports the efficacy of FFC for the rapid and sensitive screening of platelet donations for bacteria.
Department of Physics and Astronomy, University of Wyoming, Laramie, WY, USA.|SoftRay Inc, Laramie, WY, USA.
Paul
P
Johnson
Molecular Medicine Program, University of Utah, Salt Lake City, UT, USA.
Mika
M
Moriwaki
College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, USA.
Joseph
J
Johnson
D001419:Bacteria / Q000302:isolation & purification*; D001792:Blood Platelets / Q000166:cytology* / Q000382:microbiology*; D058731:Blood Safety; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D016014:Linear Models; D008828:Microbiological Techniques / Q000379:methods*; D017713:Platelet Transfusion; D015203:Reproducibility of Results
bacteria; biodetection; cytometry; fountain flow; platelets