504 



ORDER IV. EUBACTERIALES 



curved chains; in gelatin media filaments form which may subdivide into coccoid elements. 

 Not encapsulated. Motile with peritrichous flagella. Gram-positive. Carbohydrates not 

 attacked. Facultatively anaerobic. Found in decomposing materials. 

 The type species is Kurthia zopfii (Kurth) Trevisan. 



Key to the species of genus Kurthia. 

 I. Gelatin not liquefied. 



A. Hydrogen sulfide not produced; putrid odor produced in cultures. 



1. Kurthia zopfii. 



B. Hydrogen sulfide produced; no putrid odor produced in cultures. 



2. Kurthia variabilis. 

 II. Gelatin rapidly liquefied. 



3. Kurthia bessonii. 



1. Kurthia zopfii (Kurth, 1883) Trevi- 

 san, 1885. (Bacterium zopfii Kurth, Bericht. 

 d. deutsch. Bot. Gesellschaft, 1, 1883, 97; 

 Trevisan, Atti della Accad. Fisio-Medico- 

 Statistica in Milano, Ser. 4, 3, 1885, 92.) 



zop'fi.i. M.L. gen. noun zopfii of Zopf; 

 named for W. Zopf, a German botanist. 



Description based on original descriptions 

 and that of Wenner and Rettger (Jour. 

 Bact., 4, 1919, 350). 



Rods, 0.8 by 3.5 microns, with rounded 

 3nds. In liquid media, long, evenly curved 

 chains are formed; in gelatin media the 

 chains are twisted, braided and clumped 

 into knots. From these knots filaments push 

 out, laterally then anteriorly, which may 

 subdivide into coccoid elements. Not en- 

 capsulated. Motile by means of peritrichous 

 flagella. Gram-positive. 



Gelatin colonies: Radiate, filamentous, 

 gray. 



Gelatin stab: Arborescent growth in stab. 

 No liquefaction. 



Agar colonies: Fimbriate. 



Agar slant: Spreading, gray, fimbriate 

 growth. 



Broth: Slow, moderate growth; putrid, 

 ammoniacal odor produced. 



Litmus milk: No change. 



Potato: Moderate, gray growth; medium 

 becoming dark. 



Carbohydrates not attacked. 



Indole not produced. 



Hydrogen sulfide not produced. 



Nitrites not produced from nitrates. 



Aerobic, facultatively anaerobic. 



Optimum temperature, between 25° and 

 30° C. 



Comments: Some workers make a dis- 

 tinction between Kurthia zopfii Trevisan and 

 Kurthia zenkeri Bergey et al., mainly on 

 their ability or inability to form an arbores- 

 cent growth in a gelatin stab. However, 

 according to Chester (Man. Determ. Bact., 

 1901, 249), division of these organisms into 

 two species does not seem advisable: the 

 formation of an arborescent growth is too 

 variable a character on which to base species 

 differentiation. This view is also shared by 

 Wenner and Rettger (op. cit., 1919, 351). 



Source: Isolated from hen manure. 



Habitat: Foimd in decomposing mate- 

 rials. 



2. Kurthia variabilis Severi, 1946. 

 (Giorn. di Batteriol. e Immunol., 46, 1946, 

 107.) 



va.ri.a'bi.lis. L. adj. variabilis variable. 



Rods, 0.7 by 1.5 to 2.0 microns, frequently 

 curved, growing out into filaments 10 to 30 

 microns long; these filaments later divide 

 in two or form short chains. Motile by means 

 of peritrichous flagella. Gram-positive. 



Gelatin stab: No liquefaction. Grayish 

 growth along the stab. 



Agar colonies: 1 to 2 mm in diameter, 

 grayish white, glossy, smooth; regular mar- 

 gins. 



Agar slant: Slender, grayish white, trans- 

 lucent, slightly viscid. 



Broth: Moderate, uniform turbidity; thin 

 membrane. Sediment at first slight, later 

 abundant. 



Litmus milk unchanged. 



Methylene blue not reduced. 



Neutral red reduced. 



