Growth characteristics of large- and small-colony types of Mycoplasma mycoides subsp. mycoides on 5% sheep blood agar.

Mycoplasma mycoides subsp. mycoides of the large-colony (LC) type was isolated in pure culture on 5% sheep blood agar plates inoculated with lung specimens from a 4-month-old Toggenburg goat. The growth characteristics of this isolate, of four known LC types, and of five known small-colony (SC) types of M. mycoides subsp. mycoides were compared on 5% sheep blood agar at 2, 5, and 7 days. The SC types were not visible at 2 days and did not grow larger than 0.1 mm, whereas the LC types were visible in 2 days and increased in diameter over 7 days to between 0.4 and 0.7 mm. These results indicate that growth on 5% sheep blood agar can be used as an additional marker in differentiating LC and SC types of M. mycoides subsp. mycoides.