Genome sequence of the thermophilic fresh-water bacterium Spirochaeta caldaria type strain (H1T), reclassification of Spirochaeta caldaria, Spirochaeta stenostrepta and Spirochaeta zuelzerae in the genus Treponema as Treponema caldaria comb. nov., Treponema stenostrepta comb. nov., and Treponema zuelzerae comb. nov., and emendation of the genus Treponema

Table 6. Typical features of reference taxa compared to the three Spirochaeta species placed within Treponema.

	S. caldaria [1]	S. zuelzerae [62]	S. stenostrepta [63]	Genus Spirochaeta [31,34–36,55]	Genus Treponema [55,64]
Cell shape	helical	helical	helical	helical; spherical bodies under unfavorable growth conditions	helical; spherical bodies under unfavorable growth conditions
Pathogenicity	non pathogenic	non pathogenic	non pathogenic	non pathogenic	some species are pathogenic
Biotic relationship	free living	free living	free living	free living	primarily host-associated
Size [µm]	0.2–0.3 by 15–45	0.2–0.35 by 8–16	0.2–0.3 by 15–45	0.2–0.75 by 5–250	0.1–0.7 by 5–20
Motility	motile	motile	motile	motile	motile
Flagellation	flagella 1-2-1	flagella 1-2-1	2 periplasmic flagella	2 periplasmic flagella (exception: S. plicatillis, which has many flagella)	one or more periplasmic flagella
Relationship to O ₂	obligately anaerobe	obligately anaerobe	obligately anaerobe	obligately anaerobe or facultatively anaerobe	obligately anaerobe or microaerophilic
Utilizes	carbohydrates, no amino acids	carbohydrates	carbohydrates	a variety of carbohydrates, no amino acids	carbohydrates or amino acids
Fermentation products	acetate, lactate, CO₂, H₂	acetate, lactate, CO₂, H₂	acetate, ethanol, CO₂, H_2, (lactate)	acetate, ethanol, CO₂, H₂
G+C content [mol%]	46	56	60	51–65 [35] 44–65 [34]	37–54

ISSN: 2524-6372