The exogenous SsuDAT1I restriction-modification (R-M) system was first found in a field isolate of Streptococcus suis serotype 2. Isoschizomers of the R-M system were found in the same chromosomal locus in a field isolate of serotype 1/2 and the reference strains of serotypes 3, 7, 23, and 26. The R-M gene sequences in serotypes 1/2, 3, 7, and 23 were very similar to those of SsuDAT1I, whereas those in serotype 26 were less similar. These results indicate intraspecies recombination among them and genetic divergence through their evolution. (Molecular Bacteriology Section, Department of Infectious Diseases TEL +81-298-38-7743)
Reference:
Sekizaki et al. (2001) J. Bacteriol. 183:5436-5440.
