FAMILY XI. PROPIONIBACTERIACEAE 



577 



Genus II. Biityribacterium Barker and Haas, 1944'* 

 (Jour. Bact., 47, 1944, 301.) 



Bu.ty.ri.bac.te'ri.um. Gr. noun hutynnn butter; M.L. adj. butyricus butyric; Gr. dim. 

 noun bacterium a little rod; M.L. neut.n. Butyribacterium the butyric bacterium. 



Straight or slightlj' curved rods. Non-motile. Gram-positive. Anaerobic to microaero- 

 philic. Ferment carbohj'drates and lactic acid, forming acetic and butj'ric acids and carbon 

 dioxide. Generally catalase-negative but sometimes weakly positive. From the intestinal 

 contents of vertebrates so far as known. 



The type species is Butyribacterium rettgeri Barker and Haas. 



1. Butyribacterium rettgeri Barker 

 and Haas, 1944. (Strain 32, Lewis and Rett- 

 ger. Jour. Bact., 40, 1940, 298; Barker and 

 Haas, Jour. Bact., 47, 1944, 303.) 



ret'tge.ri. M.L. gen. noun rettgeri of Rett- 

 ger; named for L. F. Rettger, one of the 

 bacteriologists who first isolated this organ- 

 ism. 



Rods straight or slightly curved, 0.7 by 

 2.3 microns, occurring singly, in pairs and 

 in short chains. Non-motile. Not encap- 

 sulated. No branched cells observed, but 

 some cells have swollen club-shaped ends. 

 Gram-positive. 



Glucose-cysteine agar colonies: Circular, 

 translucent, often with opaque center, gray- 

 ish white with yellowish tinge, convex when 

 small, later umbonate, glistening, smooth, 

 finely granular, edges entire or finely irreg- 

 ular; develop slowly, attaining a diameter 

 of 1.5 mm in 7 days. 



Tryptone-yeast extract-lactate agar col- 

 onies: Similar to those described above 

 except larger (2 mm in 4 days at 37° C.) ; 

 pulvinate rather than umbonate in cross 

 sections. 



Glucose-cysteine broth: Abundant tur- 

 bidity and sediment; no pellicle. 



Agar stab (King and Rettger's medium, 

 Jour. Bact., 44, 1942, 302): Heavy growth 

 in 2 days. Gas production often causes slight 

 splitting of agar. 



Acetic and butyric acids and carbon diox- 

 ide produced from glucose and maltose; 

 occasionally a small amount of visible gas 

 is produced. Lactic acid fermented readily 

 without visible gas. Arabinose, xylose, lac- 

 tose, sucrose, trehalose, rhamnose, man- 

 nitol, sorbitol, dulcitol and glycerol are not 

 fermented. 



Not proteolytic. 



Indole not produced. 



Hydrogen sulfide not produced. 



Generally catalase-negative. 



Anaerobic. 



Temperature relations: Optimum, 37° C. 

 Minimum, 15° C. Maximum, between 40° 

 and 45° C. 



Source: Isolated from the intestinal con- 

 tents of a white rat. 



Habitat: Presumably found generally in 

 the intestines of mammals. 



Genus III. Zymobaeterium Wachsman and Barker, 1954''\ 

 (Jour. Bact., 68, 1954, 400.) 



Zy.mo.bac.te'ri.um. Gr. noun zyme leaven, ferment; Gr. dim. neut.n. bacterium a small 

 rod; M.L. neut.n. Zymobaeterium ferment rodlet. 



Rods which occur singly or in chains. Non-motile. Gram-positive. Anaerobic or micro- 

 aerophilic. Catalase-negative. Carbohydrates are utilized, glucose being converted mainly 

 to ethanol and carbon dioxide with small amounts of acetic and possibly lactic and formic 

 acids. 



The type species is Zymobaeterium oroticum Wachsman and Barker. 



* Prepared by Prof. H. A. Barker, University of California, Berkeley, California, Novem- 

 ber, 1954. 



t Prepared by Prof. H. A. Barker, University of California, Berkeley, California, Novem- 

 ber, 1954. 



