Author
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Stanton, Thaddeus |
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Submitted to: Bergey's Manual of Systematic Bacteriology
Publication Type: Book / Chapter Publication Acceptance Date: 2/16/2006 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Brachyspire are helical shaped bacteria with regular coiling patterns. Cells measure 2 to 12 um by 0.2 to 0.4 um. Unicellular, but dividing pairs of cells and sometimes chains of three or more cells can be observed in growing cultures. Under unfavorable growth conditions, spherical or round bodies are formed. Gram reaction negative. Motile by periplasmic (internal) flagella. Flexing and creeping motility at 22 deg C; translational movement at 37 to 42 deg C. Obligately anaerobic, aerotolerant. Cells have a typical spirochete cell ultrastructure, consisting of an outer sheath, helical protoplasmic cylinder and internal flagella wrapped around the protoplasmic cylinder and inside the outer sheath. Cell ends may be blunt or pointed. Brachyspire cells have 8 to 30 flagella per cell depending on the species (flagellar number usually correlates with cell size – species of a smaller cell size have fewer flagella). Flagella attach subterminally and overlap in the middle of the cells. Cultured anaerobically on commercially available media (trypticase soy or brain heart infusion broths) containing a carbohydrate growth substrate and supplemented with defibrinated blood or animal serum (calf). Grows at 36-42 deg C, optimally at 37-39 deg C. Population doubling times on glucose in broth cultures are 2 to 4 h (not reported for B. aalborgi). Chemoorganotrophic, using various carbohydrates for growth. Consume oxygen during growth in culture broth beneath a 1% oxygen atmosphere. Possess NADH oxidase for reducing molecular oxygen. Acetate, butyrate, H2, and CO2 are major endproducts of anaerobic glucose metabolism. H2 is produced in higher amounts than CO2. Weakly hemolytic except for B. hyodysenteriae which exhibits Beta-hemolysis (strongly hemolytic). Associated with animal and human hosts. Some species are pathogenic. The genus Brachyspira is distinguished from other spirochete genera based on 16S rRNA gene sequences. Brachyspira species share high 16S rRNA sequence similarity and have been differentiated by DNA-DNA relative reassociation and MLEE analyses. Shares with other spirochete genera the property of insensitivity to the antibiotic rifampin. The moles% G + C content of the DNA is 24.5 to 27.1%(Tm). |
