Conversion of DL-threonine, D-threonine and 2-oxobutyrate into propionate and 2-hydroxybutyrate by Fusobacterium species

The present investigation examined DL -threonine, D- threonine and 2-oxobutyrate conversion into propionate and 2-hydroxybutyrate by various type strains and clinical isolates of Fusobacterium. Except for Fus. naviforme , the type strains were able to produce varying degrees of propionate and/or 2-hydroxybutyrate from DL -threonine. Additionally, D -threonine was converted into an equimolar amount of propionate by Fus. necrophorum subsp. necrophorum , Fus. nucleatum subsp. nucleatum and Fus. varium , and to a lower but significant amount by Fus. mortiferum and Fus. perfoetens. However, the level of propionate remained unchanged for Fus. nucleatum subsp. fusiforme , Fus. nucleatum subsp. vincentii , Fus. naviforme , Fus. necrophorum subsp. funduliforme , Fus. gonidiaforme and Fus. russii. 2-Oxobutyrate was fermented to propionate by all type strains, although Fus. russii reduced it mainly to 2-hydroxybutyrate. Thus, an attempt was made to make use of these features in order to identify clinical isolates.