An evaluation of the taxonomy of Propionibacterium
The object of this study was to reevaluate speciation of Propionibacterium by using numerical taxonomy. Fifty-six cultures representing eight species were studied. Thirty-eight morphological and physiological features were employed in the calculation of matching coefficients which were used to sort the cultures into groups. The results suggest a need for species consolidation; for example, Propionibacterium shermanii could appropriately become P. freudenreichii var. shermanii. Close resemblances were found between P. rubrum, P. peterssonii, and P. jensenii. Propionibacterium arabinosum and P. pentosaceum formed another mutually similar group. Further studies using additional cultural, physiological, serological, genetic, and phage host-range characteristics should be instituted to establish an improved classification of propionibacteria.