ISOLATION FROM THE RUMEN OF A NEW ACETOGENIC BACTERIUM PHYLOGENETICALLY CLOSELY-RELATED TO CLOSTRIDIUM-DIFFICILE

Five strains of filamentous acetogenic bacterium were isolated from hi gh dilutions of ruminal content of newborn lambs. These Gram-positive spore-forming bacteria grew either chemolithotrophically with H-2 + CO 2 or chemo-organotrophically with glucose, cellobiose, fructose, malto se, mannose and syringic acid. The DNA base composition of the five st rains were between 29.1 and 31.3 mol% G + C. Their temperature and pH optimum for growth were 35-40 degrees C and 6.5-7.0, respectively. The full 16S rRNA gene sequence analysis of the reference strain indicate d that it was most closely related to Clostridium difficile. The seque nce similarity value between the 16S rRNA gene of the reference strain and this pathogenic strain was 99.7%. (C) 1998 Academic Press.