Detection of bacteria in WBC-reduced PLT concentrates using percent oxygen as a marker for bacteria growth.
BACKGROUND
The risk of receiving a PLT concentrate (PC) contaminated with bacteria may be 1000-fold greater than that of pathogenic viral transmission, yet surveillance for this risk is not generally practiced. A novel bacteria detection system (BDS) that overcomes the limitations of current systems is described. The BDS monitors percent oxygen (%O2) in air above aliquots of PCs that have been filtered to remove the confounding effect of respiring PLTs and residual WBCs.


METHODS
One-day-old WBC-reduced whole-blood-derived PCs (WBPCs) were inoculated with bacteria at 100 to 500 CFU per mL. After 30 minutes, 2- to 3-mL aliquots were processed through a PLT-reducing filter into a sample pouch containing sodium polyanethol sulfonate and entrained air. After incubation at 35 degrees C for at least 24 hours, the %O2 was measured within the pouch. Noninoculated WBC-reduced WBPCs (n = 155), confirmed free of bacteria by routine culture, were tested in a like manner. Results from the latter group of WBC-reduced WBPCs were used to distinguish contaminated from noncontaminated units.


RESULTS
After a 24-hour incubation at 35 degrees C, 195 (96.5%) of the 202 sample pouches obtained from inoculated units were detected by the BDS. After an additional 6 hours at room temperature, those that remained and were tested were found positive. None of the noninoculated controls produced a positive reading.


CONCLUSIONS
The BDS is easy to use and provides good levels of sensitivity and specificity.
Ortolano
Girolamo A
GA
Pall Corporation, Scientific and Laboratory Services, Research and Development, East Hills, New York, USA. jerry_ortolano@pall.com
Freundlich
Lawrence F
LF
Holme
Stein
S
Russell
Rosalind L
RL
Cortus
Mary Anne
MA
Wilkins
Karen
K
Nomura
Hiromi
H
Chong
Chiyong
C
Carmen
Raleigh
R
Capetandes
Anthony
A
Wenz
Barry
B
D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000175:diagnosis / Q000517:prevention & control* / Q000635:transmission; D001431:Bacteriological Techniques / Q000295:instrumentation / Q000379:methods*; D015415:Biomarkers; D001792:Blood Platelets / Q000382:microbiology*; D006801:Humans; D007962:Leukocytes / Q000166:cytology*; D010100:Oxygen / Q000032:analysis*; D017713:Platelet Transfusion; D012680:Sensitivity and Specificity
D015415:Biomarkers; D010100:Oxygen