Abstracts (complete list) - Wissenschaft Online

Tatiana Binder, Rodica Bernatowicz, Michael Rothballer, Michael Schmid, Susanne
Krauss-Etschmann, Dolores J. Schendel, Anton Hartmann
QUANTITATION OF LIVE VERSUS DEAD PROBIOTIC BACTERIA
Background: The effect of probiotic bacteria on the immune system is subject of
intensive research. However, live probiotic bacteria might induce different signals
versus dead probiotic bacteria in bioassays, e.g. using dendritic cells. Therefore, we
asked how standard culture affects the viability of different probiotic bacteria.
Methods: Lactobacillus rhamnosus GG (LGG, Valio Ltd, Finland), Lactobacillus reuteri
ATCC 55730 (BioGaia AB, Sweden), Bifidobacterium sp. 420 (Bifidobacterium lactis,
Danisco Germany GmbH), Lactobacillus acidophilus LA-2, Lactobacillus acidophilus LA-5,
Lactobacillus paracasei subsp. paracasei LC-01, Bifidobacterium animalis BB-12 and
Bifidobacterium longum BB-46 (Chr. Hansen GmbH, Denmark) were cultured in MRSbroth
(Merck KGaA) under anaerobic conditions for 24 hours. After cultivation the
bacterial cells were stained with a LIVE/DEAD staining kit (Invitrogen GmbH). The
percentage of dead bacteria within the total population of bacterial cells was counted
visually via fluorescence microscopy.
Results: The viability of LGG, B. lactis, LA-2, LA-5, LC-01, BB-12 and BB-46 ranged
between 94%-99%. In contrast L. reuteri yielded only around 80% live bacteria after 24
hours of cultivation.
Conclusions: Our data show that viability of different probiotic strains can vary
considerably under standard culture conditions. Therefore, the precise assessment of
the viability of bacteria is important for functional immune assays. Currently, there are
no straightforward bioassays at the single cell level available to distinguish among
active, inactive or stressed live bacterial cells.