Streptococcus salivarius, Streptococcus sanguis and Streptococcus "mitis" as indicators of contamination of root...

Small samples were taken from the first drop of saliva entering an operation field for root canal treatment isolated by rubber dam, which was intentionally leaky. The samples were primarly cultured in TAS- and BLH-medium and on MS-agar aerobically. The culture media were inoculated directly and via transport medium (VMG III). The cultures were analysed for Strep. salivarius, Strep. sanguis and/or Strep. "mitis" after subculture on MS-agar as soon as visible growth had appeared in the broth media and again after a further 2 days. The following observations were made: 1. Strep. salivarius was almost regularly found in either or both of TAS- and BLH-medium at primary culture of the samples contaminated with saliva. The result was the same whether these broth media were inoculated directly or via VMG III. 2. Strep. salivarius was always found in mixed cultures and was nearly always accompanied by Strep. sanguis and/or Strep. "mitis". 3. Strep. salivarius as well as Strep. sanguis survived two days after visible growth significantly more oftern in BLH-medium than in TAS-medium. The findings lend support to the hypothesis based on clinical studies that when present in root canal cultures Strep. salivarius is ascribable to contamination with saliva.