D. TAYLOR-ROBINSON?PLATE XLV UREAPLASMAS (T-mycoplasmas) (Shepard et al., 1974) of bovine origin cause experimental mastitis in cows (Gourlay, Howard and Brownlie, 1972;Howard, Gourlay and Brownlie, 1973). In contrast, none of six ureaplasma strains of human origin was capable of producing mastitis in cattle although two of these strains produced mastitis in goats . Cattle and goats, however, are not readily obtainable for experimental work and the use of small laboratory animals would greatly facilitate studies on ureaplasma pathogenesis and immunology. Mastitis has been produced in mice by intramammary inoculation of bacteria obtained from clinical cases of bovine mastitis (Chandler, 1970), and the purpose of this investigation was to determine whether it was possible to produce mastitis in mice with human and bovine ureaplasmas.
MATERIALS AND METHODSUreaplasma strains. Strains derived from the human genital tract, namely nos. CD408, M126/68 and CD573, have been described previously . Strain CD591 (Johnson) was isolated from the human oropharynx (Taylor-Robinson and Purcell, 1966) and strain T960 is the type strain of Ureaplasma urealyticum (Shepard et al., 1974). Strains A417, Vic9, Bu2 and BlOl were isolated from cattle (Howard et al., 1973). Ureaplasmas were grown at 37°C in either U3 broth and the corresponding solid medium (Howard et al., 1975) or a PPLO medium described by Taylor-Robinson, Addey and Goodwin (1969). Agarcontaining medium was incubated in an atmosphere of 5 % COZ in N2.Assessment of viable ureaplasmas. This was done by determining d o u r change units (c.c.u.) (Taylor-Robinson and Purcell, 1966;Gourlay et al., 1972), or by determining colonyforming units (c.f.u.).Mouse inocula. These were prepared either by centrifuging " overnight " broth cultures at lo00 g for 20 min. and resuspending the deposits in 0 . 1 5~ phosphate-buffered saline (PBS) pH 7.2, or by thawing from -70°C broth cultures containing a known number of c.f.u. and diluting them in PBS just before use to give the required number of organisms.Mice. BSVS mice bred at Compton were used, unless otherwise stated. Mice of C3H, CBA and TO strains were bred at the Clinical Research Centre.Infection and examination of mice. The technique used to inoculate mice by the intramammary route has been described previously (Chandler, 1970); the fourth gland from the front on each side (R4 and L4) was used and the volume of the inoculum was 0.0541 ml.