Objective: To identify the DNA sequences of 26 beta-hemolytic group G streptococci strains isolated from the swabs of patients in a glomerulonephritis outbreak event.
Methods: API20 Strep system and 16S rDNA sequencing were performed on all of the 26 isolated strains respectively. The dendrogram based on the analysis of the 16S rDNA sequences of four groups of G streptococci strains was constructed by the neighbor-joining method and boot-strap test.
Results: The API20 Strep system failed to identify the strains with less than 62% of success rates. All of the 26 group G beta-hemolytic streptococci isolates were identified as Streptococcus anginosus by the 16S rDNA sequencing, with more than 97% of success rates. The dendrogram illustrated that the four groups of G streptococci strains were clustered at the same branch with Streptococcus anginosus.
Conclusion: The 16S rDNA sequencing has unique advantages over the phenotypic methods. It can provide detailed information of nucleotides and identify species of beta-hemolytic G group streptococci.