Evaluation of a new transport medium for the preservation of oral streptococci.

The survival of pooled plaque bacteria and a mixed suspension of Streptococcus mutans, Streptococcus sanguis, Streptococcus mitis, and Streptococcus saliuarius were tested in three transport media. A new, non-nutritive, reduced transport fluid, RTF, was compared with VMG II and SBL, two recognized transport media. Specimens were stored in several vials of each medium and held at either 10°C or room temperature (25°C). At time intervals over a 21-day period, the number of viable colony-formingunits per ml in each vial was estimated by culture on mitis-salivarius agar. The survival of oral streptococci was enhanced by storage at 10°C. VMG II and RTF performed equally well at this temperature. RTF maintained the most constant populations of streptococci with storage at room temperature. SBL was the least suitable medium for oral streptococci.