Phylum Proteobacteria, Class Epsilonproteobacteria, Order Campylobacterales, Family Helicobacteraceae, Genus Helicobacter,
Helicobacter trogontum Mendes et al. 1996.
Synonyms: Flexispira taxon 6, Flexispira taxon 1, Flexispira taxon 4, Flexispira taxon 5, Helicobacter rappini, Flexispira rappini.
Gram-negative, fusiform cells, slightly spiral, 0.6-0.7 x 4-6 μm. Periplasmic fibers are
coiled around the cell body, giving a crisscross appearance to the bacterial surface.
Coccoid forms appear in older cultures. Motile by means of 3-7 sheathed flagella
arranged in tufts at both cell's ends. Nonsporulated.
Colonies are initially punctiform but often spread out as thin layers on the surface of
agar media after 3-5 days of microaerobic incubation at 37 ºC. Can grow at 42 ºC, but
not at 25 ºC. No growth occurs on brucella agar plates containing 1% glycine or 1.5, 2,
or 3% NaCl. Sensitive to metronidazole (4 μg) but resistant to cephalothin (30 μg) and
nalidixic acid (30 μg) in disk diffusion tests.
Isolated from colonic mucosa of rats.
- George M. Garrity, Julia A. Bell and Timothy Lilburn, 2001. Family II. Helicobacteraceae. In: Bergey’s Manual of Systematic
Bacteriology, Second edition, Vol 2, part C, George M. Garrity (Editor-in-Chief), pp 1168-1195.
- Edilberto N. Mendes, Dulciene M. M. Queiroz, Floyd E. Dewhirst, Bruce J. Paster, Silvia B. Moura, and James G. Fox. Helicobacter
trogontum sp. nov., Isolated from the Rat Intestine. Int J Syst Bacteriol October 1996 46:916-92.
Positive results for catalase, oxidase, urease, nitrate reduction, ornithine
decarboxylase, H2S production, gamma-glutamyl transpeptidase.
Negative results for growth in 1% glycine, hippurate hydrolysis.
Variable results for alkaline phosphatase (1/6).
(c) Costin Stoica