Cultivation on solid media of spirochetes in subgingival plaque from advanced marginal periodontitis in humans

Six solid substrates were compared for suitability to support growth of spirochetes from 18 subgingival plaque samples in patients with advanced marginal periodontitis. The following substrates with rabbit serum were tested: BHIA-SC + blood, RGCA-SC + blood, GM-1 +/- blood and MGM-1 +/- blood. All media contained rifampicin and polymyxin B. After incubation in a glovebox (70% N2, 20% H2, 10% CO2) for 14 days spirochete colonies were semiquantitated and the colony morphologies described. The spirochetes in six of the primary samples and in the related colonies after cultivation were identified ultrastructurally by number of endoflagella. The results showed that the colony morphologies were more related to the substrate used than to the various types of spirochetes, and that individual colonies contained different types of spirochetes. The substrates MGM-1, RGCA-SC, and BHIA-SC, all with blood, showed the highest recoveries of about 5%. Spirochetes with less than four endoflagella grew on all substrates, but the MGM-1 + blood and RGCA-SC + blood media seemed the most versatile as they showed growth of all types of spirochetes observed in the primary samples.