Photochemical treatment of platelet concentrates with amotosalen and long-wavelength ultraviolet light inactivates a broad spectrum of pathogenic bacteria.
BACKGROUND
Bacterial contamination of platelet (PLT) concentrates can result in transfusion-transmitted sepsis. A photochemical treatment (PCT) process with amotosalen HCl and long-wavelength ultraviolet light (UVA), which cross-links nucleic acids, was developed to inactivate bacteria and other pathogens in PLT concentrates.


METHODS
High titers of pathogenic aerobic and anaerobic Gram-positive bacteria (10 species), aerobic Gram-negative bacteria (7 species), and spirochetes (2 species) were added to single-donor PLT concentrates containing 3.0 x 10(11) to 6.0 x 10(11) PLTs in approximately 300 mL of 35 percent plasma and 65 percent PLT additive solution (InterSol, Baxter Healthcare) or saline. After PCT with 150 micro mol per L amotosalen and 3 J per cm(2) UVA, residual bacterial levels were detected by sensitive microbiologic methods.


RESULTS
The level of inactivation of viable bacteria was expressed as log reduction. Log reduction of Gram-positive bacteria for Staphylococcus epidermidis was > 6.6; for Staphylococcus aureus, 6.6; for Streptococcus pyogenes, > 6.8; for Listeria monocytogenes, > 6.3; for Corynebacterium minutissimum, > 6.3; for Bacillus cereus (vegetative), > 5.5; for Lactobacillus sp., > 6.4; for Bifidobacterium adolescentis, > 6.0; for Propionibacterium acnes, > 6.2; and for Clostridium perfringens, > 6.5. Log reduction of Gram-negative bacteria for Escherichia coli was > 6.4; for Serratia marcescens, > 6.7; for Klebsiella pneumoniae, > 5.6; for Pseudomonas aeruginosa, 4.5; for Salmonella choleraesuis, > 6.2; for Yersinia enterocolitica, > 5.9; and for Enterobacter cloacae, 5.9. Log reduction of spirochetes for Treponema pallidum was 6.8 to 7.0, and for Borrelia burgdorferi, > 6.9.


CONCLUSIONS
PCT inactivates high levels of a broad spectrum of pathogenic bacteria. The inactivation of bacteria in PLT concentrates offers the potential to prospectively prevent PLT-transfusion-associated bacteremia.
Lin
Lily
L
Cerus Corporation, Concord, California 94520, USA. lily_lin@cerus.com
Dikeman
Roberta
R
Molini
Barbara
B
Lukehart
Sheila A
SA
Lane
Robert
R
Dupuis
Kent
K
Metzel
Peyton
P
Corash
Laurence
L
D016470:Bacteremia / Q000517:prevention & control; D001419:Bacteria / Q000145:classification / Q000528:radiation effects*; D001420:Bacteria, Aerobic / Q000528:radiation effects; D001421:Bacteria, Anaerobic / Q000528:radiation effects; D001792:Blood Platelets / Q000382:microbiology*; D025065:Borrelia burgdorferi / Q000528:radiation effects; D011564:Furocoumarins / Q000494:pharmacology*; D006801:Humans; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000494:pharmacology; D017713:Platelet Transfusion / Q000009:adverse effects / Q000379:methods; D013242:Sterilization / Q000379:methods*; D014210:Treponema pallidum / Q000528:radiation effects; D014466:Ultraviolet Rays
D011564:Furocoumarins; D017319:Photosensitizing Agents; C118577:amotosalen