Authors:Trudy M. Wassenaar, Anke Zschüttig, Claudia Beimfohr, Thomas Geske, Christian Auerbach, Helen Cook, Kurt Zimmermann, and Florian Gunzer
The probiotic product Symbioflor2 (DSM 17252) is a bacterial concentrate of six different Escherichia coli genotypes,
whose complete genome sequences are compared here, between each other as well as to other E. coli genomes. The genome
sequences of Symbioflor2 E. coli components contained a number of virulence-associated genes. Their presence seems to be
in conflict with a recorded history of safe use, and with the observed low frequency of adverse effects over a period of more than 6 years.
The genome sequences were used to identify unique sequences for each component, for which strain-specific hybridization probes were designed.
A colonization study was conducted whereby five volunteers were exposed to an exceptionally high single dose. The results showed that the probiotic
E. coli could be detected for 3 months or longer in their stools, and this was in particular the case for those components containing higher
numbers of virulence-associated genes. Adverse effects from this long-term colonization were absent. Thus, the presence of the identified
virulence genes does not result in a pathogenic phenotype in the genetic background of these probiotic E. coli.
for 24 h or at –20 °C for a longer period. The DNA amplification was performed using genus-specific primers and genus-specific fluorescence resonance energy transfer (FRET) hybridizationprobes, previously described by Orosz et al. [ 17 ]. Each
Authors:Erika Orosz, Dorottya Kriskó, Lei Shi, Gábor L. Sándor, Huba J. Kiss, Berthold Seitz, Zoltán Zsolt Nagy, and Nóra Szentmáry
. The DNA amplification was performed using genus-specific primers and genus-specific fluorescence resonance energy transfer (FRET) hybridizationprobes, previously described by Orosz et al. [ 20 ]. Each experiment included one reaction mixture without
Authors:Markus Krohn, Thomas Wanek, Marie-Claude Menet, Andreas Noack, Xavier Declèves, Oliver Langer, Wolfgang Löscher, and Jens Pahnke
photometrically. cDNA was synthesized using the High Capacity RNA-to-cDNA Kit (Applied Biosystems, USA). Gene expression was analyzed with qRT-PCR using TaqMan HybridizationProbes. Primer sets with according TaqMan probes for Abcb1a (Mm00440761_m1), human ABCB