Strains of Mycoplasma mycoides subsp. mycoides small colony type isolated in China between 1953 and 1960 show close similarity to strains of the Africa/Australia cluster

In this study, six Chinese strains of Mycoplasma mycoides subsp. mycoides small colony type (MmmSC) isolated between 1953-1960 were analysed and their molecular characteristics compared to those of the African PG1 and Afade strains, the European C305 and 138/5 strains and the closely related caprine M. mycoides subsp.mycoides large colony type Y-goat strain. PCR amplification of long DNA fragments showed that the six Chinese strains, the PG1 strain and the Y-goat strain, just like Afade, did not have the 8.84 kb deletion characteristic of the European strains C305 and 138/5. In comparison, the lppB gene sequence of the six MmmSC Chinese strains was found to be 99% homologous to that of PG1and Afade, but <93% homologous to the Y-goat sequence. The anti-rLppB antiserum reacted with PG1, Y-goat and the six Chinese strains at 67 kDa sites in Western blot, indicating that the lppB gene and its encoding protein exist in the Chinese strains. Multilocus sequence analysis (MLSA) of MmmSC strains from various regions confirmed that the Chinese strains were identical to the African and Australian cluster. This finding was further supported by the outcome of selective primer amplification. Based on these results, it is suggested that CBPP in China may have originated from Australia.