BIPHASIC CULTURE OF ARCOBACTER SPP

Arcobacter spp. have recently been genetically differentiated as a gen us distinct from Campylobacter. Physiologically, Arcobacter spp. are a erotolerant bacteria, while Campylobacter spp. are microaerophilic. Ho wever, since Arcobacter spp. have been difficult to grow to high popul ation densities in broth media, alternative culture techniques were in vestigated. A biphasic culture system was developed in 25 cm(2) tissue culture flasks. Biphasic culture, consisting of a solid phase of 10% bovine blood agar and a liquid phase of Brain Heart Infusion broth, wa s found to increase bacterial population densities by more than 2 log( 10) cycles for strains of A. butzleri and A. skirrowii. A strain of A. cryaerophilus, which was non-culturable in broth culture, attained po pulation densities of 10(9) cells ml(-1) in biphasic culture. Neither the addition of fetal bovine serum to the liquid nor an increase in th e surface area from 25 to 75 cm(2) resulted in increased cell densitie s.