Erythrocytes as a source of essential lipids for Treponema hyodysenteriae

Abstract

Mammalian erythrocytes were tested as a nutrient source for the spirochete Treponema hyodysenteriae, the etiologic agent of swine dysentery. Brain heart infusion (BHI) broth did not support growth of T. hyodysenteriae B204 or B78. However, BHI broth supplemented with washed bovine erythrocytes, erythrocyte membranes, or cholesterol was an excellent culture medium for these strains (4 x 108 to 109 cells per ml, final population densities). Small amounts of cholesterol (3 to 10 ,ug/ml of medium) were required for maximum cell yields of strain B204. Of various sterols and sterol-like compounds tested, cholestanol and sitosterol could substitute for cholesterol. BHI-dehydrated medium extracted with CHCl3-CH30H (2:1, vol/vol) to remove lipids was used to prepare lipid-depleted culture broth. Lipid-depleted broth supplemented only with cholesterol did not support T. hyodysenteriae B204 growth. However, this same broth supplemented either with vesicles made from cholesterol and phosphatidylcholine or with washed erythrocytes was a good culture medium for the spirochete. Thus, both cholesterol and a phospholipid are needed for T. hyodysenteriae growth in lipid-depleted broth. Mammalian erythrocytes can be used by the spirochete as a source of these lipids.

Isolation, Oxygen Sensitivity, and Virulence of NADH Oxidase Mutants of the Anaerobic SpirocheteBrachyspira(Serpulina)hyodysenteriae, Etiologic Agent of Swine Dysentery

“…B. hyodysenteriae B204 is a virulent strain commonly used in experimental infections of swine in the United States. Cells were routinely cultured, with stirring, in BHIS broth (Difco brain heart infusion broth containing 10% [vol/vol] heat-treated calf serum) beneath an initial culture atmosphere of 1% O 2 -99% N 2 (40,42). Trypticase soy blood (TSB) agar medium was made by adding defibrinated bovine blood (final concentration, 5% [vol/vol]) to sterile, melted Trypticase soy agar medium containing glucose (BBL, Becton Dickinson, Cockeysville, Md.…”

Reduced virulence of Serpulina hyodysenteriae hemolysin-negative mutants in pigs and their potential to protect pigs against challenge with a virulent strain

“…hyodysenteriae wild-type strain and the tlyA mutant strain were able to colonize the porcine gastrointestinal tract (Table 1). Since S. hyodysenteriae may need the activity of a hemolysin as a scavenger of nutrients both in vitro (16) and in vivo, a strain lacking a hemolysin is probably less able to compete for available nutrients and therefore to survive.…”

Cloning and expression of a Serpula (Treponema) hyodysenteriae hemolysin gene

“…The pathology of SD also supports the presence and activity of a cytotoxin/ hemolysin molecule during the acute phase of the disease. In vitro, both cholesterol and phospholipids are needed for S. hyodysenteriae growth in lipid-depleted broth cultures (36), and cholesterol appears to be an essential growth factor for the spirochete (19,35,36). The cytotoxin/hemolysin appears to be an important virulence factor.…”