Clustering of Saccharomyces boulardii strains within the species S. cerevisiae using molecular typing techniques.
OBJECTIVE
This study was undertaken to characterize and differentiate therapeutically relevant Saccharomyces yeasts. Among the isolates were so-called Saccharomyces boulardii strains, which are considered as probiotic agents, but whose taxonomic assignment is controversial. Moreover, the discriminative power of the applied molecular typing techniques should be evaluated.


RESULTS
Genotyping was performed using species-specific polymerase chain reaction (PCR), randomly amplified polymorphic DNA-PCR, restriction fragment length polymorphism analysis of rDNA spacer regions and pulsed-field gel electrophoresis. Species-specific PCR assigned all of the product isolates to the species S. cerevisiae. By combining the other techniques, all isolates could be discriminated. Moreover, it could be demonstrated that probiotic S. boulardii strains form a separate cluster located within the species.


CONCLUSIONS
With the exception of species-specific PCR, all of the applied methodologies were suitable for subspecies typing and indicated a close relationship between the probiotic strains.


CONCLUSIONS
The methods applied in this study are considered powerful tools for quality control of therapeutically relevant yeasts. It is of crucial importance, especially regarding S. boulardii yeasts, to verify the identity of the correct strain, since the beneficial properties are considered to be strain-specific.
Mitterdorfer
G
G
Department of Dairy Research and Bacteriology, University of Agricultural Sciences, Vienna, Austria.
Mayer
H K
HK
Kneifel
W
W
Viernstein
H
H
D004271:DNA, Fungal / Q000032:analysis; D021903:DNA, Ribosomal Spacer / Q000032:analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D016533:Mycological Typing Techniques; D016133:Polymerase Chain Reaction; D019936:Probiotics; D019105:Random Amplified Polymorphic DNA Technique; D012440:Saccharomyces / Q000145:classification* / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000145:classification* / Q000235:genetics*; D013045:Species Specificity
D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer