Saponin, an inhibitory agent of carbon dioxide production by white cells: its use in the microbiologic examination of blood components in an automated bacterial culture system.
BACKGROUND
Blood components with a white cell count > 100 x 10(9) per L may cause false-positive results when the BacT/Alert system is used for the microbiologic examination. The effects of different concentrations of saponin on bacterial growth and on carbon dioxide production by blood fractions with a high white cell count, in particular peripheral blood progenitor cells and buffy coats, were investigated.


METHODS
The effect of saponin on carbon dioxide production was studied by adding different fractions of white cell-rich material (buffy coat or leukapheresis material) to BacT/Alert culture bottles with or without saponin and incubating these bottles. Five bacterial strains were used to inoculate the culture bottles at four levels ranging from about 1 colony-forming unit per mL to about 10(3) colony-forming units per mL. Aerobic and anaerobic bottles with and without saponin were used.


RESULTS
It was demonstrated that the addition of 0.5 percent saponin to BacT/Alert culture bottles effectively inhibited carbon dioxide production, without affecting bacterial growth.


CONCLUSIONS
Saponin at a concentration of 0.5 percent is a valuable additive to BacT/Alert culture media because it prevents false-positive results in the examination of white cell-rich blood components.
van Doorne
H
H
Department of Pharmaceutical Technology and Biopharmacy, University of Groningen, The Netherlands.
van der Tuuk Adriani
W P
WP
van de Ven
L I
LI
Bosch
E H
EH
de Natris
T
T
Smit Sibinga
C T
CT
D001431:Bacteriological Techniques; D002245:Carbon Dioxide / Q000378:metabolism*; D015169:Colony Count, Microbial; D003470:Culture Media / Q000737:chemistry; D006412:Hematopoietic Stem Cells / Q000382:microbiology; D006801:Humans; D007937:Leukapheresis; D007962:Leukocytes / Q000187:drug effects* / Q000378:metabolism*; D012503:Saponins / Q000032:analysis / Q000494:pharmacology*; D013997:Time Factors
D003470:Culture Media; D012503:Saponins; D002245:Carbon Dioxide