Ribotyping of Streptococcus agalactiae strains isolated from vaginas of asymptomatic women.

One hundred and eleven strains of Streptococcus agalactiae isolated from vaginas of asymptomatic women were characterized by determination of restriction length polymorphism profiles of rDNA regions (rDNA RFLP patterns) and serotyping. Thirty-five different PstI rDNA RFLP patterns were identified. Half of the strains fell into only seven of these 35 groups. No correlation between serotypes and rDNA RFLP patterns was found. These results indicate that (i) the genetic diversity of the S. agalactiae species is relatively limited and (ii) determination of rDNA RFLP patterns can be used as a typing system only in conjunction with serotyping.