Anaerobiospirillum thomasii sp. nov., an anaerobic spiral bacterium isolated from the feces of cats and dogs and from diarrheal feces of humans, and emendation of the genus Anaerobiospirillum.

Thirty-seven similar strains isolated from feces of cats and dogs and from human diarrheal feces had characteristics of the genus Anaerobiospirillum. These organisms were distinguished from the only previously described Anaerobiospirillum species, Anaerobiospirillum succiniciproducens, by producing acid from adonitol but not from fructose, raffinose, or sucrose and by the lack of alpha-glucosidase. The G + C contents of the DNAs of the new strains were 39 to 42 mol%. The results of morphological, physiological, DNA G + C content, and DNA homology studies support the proposal that the description of the genus Anaerobiospirillum should be emended so that a new species can be included in the genus. The new species Anaerobiospirillum thomasii is proposed, with strain A273/88 (= NCTC 12467) as the type strain.