Rapid identification of dairy Propionibacterium species by restriction analysis of the insertion within the 23S rRNA gene

Abstract

-An amplified sequence of approximately 350 bases from the 23S rRNA gene of each bacteria was used to identify 37 strains of dairy propionibacteria. After generation of the fragment by PCR (polymerase chain reaction), it was eut with the restriction endonuclease MspI. The resulting electrophoretic pattern showed a distinct profile for each of the Propionibacterium species. Purification of DNA was not necessary and the analyses could also be performed with crude bacterial extract. A collection of anaerobie bacteria commonly found in milk and milk products was also submitted to the analysis. None yielded the same pattern as propionibacteria.The analysis of the propionibacteria was compared to that performed by electrophoresis of the soluble cell-free protein extracts and that of c1assical microbiological tests. Our method gave identical results and was less time consuming (results could be obtained within a single day and were also easier to read) than both the c1assical tests and protein electrophoresis. © Inra/Elsevier, Paris.

In vitro and in vivo gastrointestinal survival, antibiotic susceptibility and genetic identification of Propionibacterium freudenreichii ssp. shermanii JS

“…Identification of Propionibacterium species was performed according to Fessler, Casey, and Puhan (1998). Briefly, part of the 23S rDNA was amplified followed by restriction analysis with MspI (New England Biolabs, Ipswich, MA, USA).…”

Biodiversity, dynamics, and characteristics of Propionibacterium freudenreichii in Swiss Emmentaler PDO cheese

“…Although the culture-independent assay was shown to yield similar results when compared with plate count assays, the study concluded that plate counts were more accurate than qPCR for cell concentrations below 10 3 cells/g of food. In the present study, sodium lactate agar was used for the initial growth step since this medium was previously shown to enable growth of all species of dairy propionibacteria (Fessler et al 1998). …”

“…In practice, the introduction of these systems resulted in a drastic reduction of cases of late fermentation during the long-term ripening of Emmentaler PDO cheese. Propionibacteria are naturally present in raw milk at concentrations of 10 1 -10 3 cfu.mL -1 , and little is known regarding their influence on Emmentaler PDO cheese quality (Fessler et al 1997;Fessler et al 1998).…”