Characterisation of anaerobic curved rods (Mobiluncus spp.) isolated from the urogenital tract

Divisions of Sexually Transmitted Diseases and Communicable Diseases, Clinical Research Centre, Watford Road, Harrow, Middlesex HA1 3UJ Correspondence should be sent to D. Taylor-Robinson. Received June 2, 1986 Accepted August 12, 1986 Thirty-two strains of anaerobic curved rods isolated from vaginal secretions and one isolated from seminal fluid were examined. Growth of all strains on solid media was superior to growth in liquid media, and at 37°C they grew both anaerobically and in O 2 5% in N 2 ; they also grew anaerobically at 33°C but not at 42°C. No growth factors were identified, but strains grew more profusely at p H values above 5–0. The strains were screened in 80 biochemical tests, and for their susceptibility to 30 different antimicrobial agents. Most of the tests did not differentiate between the strains, but they were divided into four groups on the basis of cell morphology, metronidazole susceptibility, β-galactosidase activity and arginine and hippurate hydrolysis. Group 1 consisted of 19 strains conforming to the species M. curtisi ; group 2 consisted of five strains conforming to the species M. mulieris ; group 3 consisted of five strains that resembled M. curtisi morphologically, and group 4 consisted of four strains that resembled M. mulieris morphologically, but the strains in the latter two groups reacted differently in at least one of the three major differential biochemical tests. Of three strains of M. curtisi and three of M. mulieris chosen at random, one of M. mulieris had a SDS-PAGE and fast-protein liquid chromatography protein profile indistinguishable from that of M. curtisi. We conclude that further efforts are required to clarify the taxonomic status of the genus Mobiluncus. * Visiting worker from Clinica Medica Generale e Terapia Medica III, Universita Degli Studi di Roma, Italy.