A numerical taxonomic study of Propionibacterium strains from dairy sources

Abstract

T.J. BRITZ AND K‐H.J. RIEDEL. 1991. Phenotypic results from 81 tests conducted on 73 propionibacteria, including five type strains, 22 reference strains, unidentified propionibacteria and strains isolated from dairy sources, were analysed by numerical taxonomy. Characters giving uniform results were excluded. With the simple matching coefficient and the single linkage cluster analysis, 61 cultures were recovered in five major clusters. Final linkage of all the Propionibacterium cultures examined was at the 77% S‐level. The results clearly showed that it was possible to distinguish between the ‘classical’ and ‘cutaneous’Propionibacterium spp., corresponding with the type habitat of each group. The major ‘classical’ clusters were equated with the P. freudenreichii, P. thoenii, P. jensenii and P. acidipropionici species, while the only major ‘cutaneous’ cluster was equated with the P. acnes species. The major clusters were identified by relating them to specific type strains and by comparing phenotypic characteristics. The differentiating characteristics of each cluster were determined. The largest cluster, representing 37% of the strains, was equated with P. jensenii but contained cultures that produced an atypical brown/red pigment. These strains, although positively identified as P. jensenii, could also be identified as the ‘old’‘P. rubrum’ species. Thus if pigmentation is used as differential characteristic two distinct groups of propionibacteria could be identified within the P. jensenii species.

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

“…Both of the se species could clearly be differentiated with the method described here and the earlier P. rubrum was classified under P. jensenii ( figure 3). This finding is in agreement with the classification of P. rubrum as P. jensenii by Britz and Steyn [7], Britz and Riedel [6], de Carvalho et al…”

“…'" " " '" '" '" '" " " '" methods may be ambiguous [6,II]. The greatest problem seems to be the distinction between P. jensenii and P. thoenii.…”

“…This fragment was not or only partially eut with the restriction endonucIease Mspi. The genus of propionibacteria was clearly distinguishable from the other tested bacteria even without cutting the fragment of about 350 bases (figures [6][7][8][9]. Approximately 100 unidentified strains isolated from rnilk, growing on lactate, and morphologically as weIl as microscopically similar to propionibacteria were analyzed.…”

Propionibacterium species diversity in anaerobic digesters

“…According to the species description, P. jensenii strains typically produce a creamish pigment (Cummins and Johnson, 1986). Similar problems in the taxonomy of members of the Propionibacterium have previously been encountered (Britz and Riedel, 1991).…”

“…Phenotypic tests were determined in a Forma Scientific anaerobic cabinet, using oxygen-free nitrogen (Holdeman et al, 1977). The utilization of 74 substrates and biochemical tests on the isolates, four type strains and a reference strain were determined as previously described (Britz and Riedel, 1991). The growth at 25, 30, 35, 37 and 40°C was determined by comparison of the optical density every 4 h. Morphological characteristics were determined with bright-field microscopy of Gram-stained preparations, motility after 48 h in MRS medium (Merck), and colony pigmentation after 10 days on YEL plates.…”