Taxonomic studies of the genus Clostridium: Clostridiwn bifermentans and

SUMMARY: In an attempt to elucidate the taxonomic relationship of CZostridium bifermentans and C. sordeZZii about sixty strains assigned to one or other of the two species were examined. Two groups of strains differing in their cultural and biochemical properties were recognized. One closely resembled the type culture of C. bifermentans (Tissier & Martelly, 1902), and the other, in which some strains were pathogenic, resembled the C. sordeZZii isolate ‘82 ’ of Sordelli. The former of these groups is clearly to be regarded as C. bifermentans and the latter as C. sordellii. It has been shown that the two species, although similar in many respects, are distinct and easily distinguishable. In view of this, the present practice of some bacteriologists of combining the two species under the name C. bifermentans is incorrect and should be discontinued. Although Clostridium bifermentans was first isolated by Tissier & Martell y in 1902, and C. sordellii by Sordelli in 1922, the taxonomic relationship of these two organisms is still the subject of controversy. The use of either of two criteria (cultural and biochemical character or pathogenicity) for th