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Comparison of Five Selective Media for the Growth and Enumeration of Streptococcus Mutans
Author(s) -
Wan AKL,
Seow WK,
Walsh LJ,
Bird PS
Publication year - 2002
Publication title -
australian dental journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.701
H-Index - 71
eISSN - 1834-7819
pISSN - 0045-0421
DOI - 10.1111/j.1834-7819.2002.tb00298.x
Subject(s) - bacitracin , streptococcus mutans , agar , microbiology and biotechnology , serial dilution , bacteria , dental plaque , streptococcus mitis , food science , agar plate , chemistry , colony forming unit , biology , streptococcus , medicine , antibiotics , genetics , alternative medicine , pathology
Background: Although a few growth media are available for selective isolation of the cariogenic bacteria, Streptococcus mutans (S. mutans), it is still unclear as to which is the most efficacious. This study compared the selectivity and sensitivity of five different media for growing a laboratory strain of S. mutans (NCTC 10449), and for enumerating S. mutans from teeth of a group of young children, aged 2–10 years. Methods: The media tested in this study were mitis salivarius with bacitracin (MSB), mitis salivariuskanamycin‐bacitracin (MSKB), glucose‐sucrosetellurite‐bacitracin (GSTB), trypticase soy‐sucrosebacitracin (TYS20B) and tryptone‐yeast‐cysteinesucrose‐bacitracin (TYCSB) agars. These were prepared according to the respective manufacturer's instructions. Results: The results showed that at concentrations of bacteria 1times10 3 to 1X10 10 /mL, the recovery of the laboratory S. mutans strain was highest in TYCSB agar, followed by in descending order by TYCSB, MSB, GSTB, and MSKB (p<0.01). Similar results were obtained using dental plaque samples collected from swabs of the teeth of a group of children. In the clinical samples, TYCSB again showed the highest recovery rates of S. mutans compared to the other four media. Results were reproduced at dilutions of the samples at 1:20times10 6 to 1:2times10 6 , and S. mutans concentrations of 1.6 to 7.7 Log 10 CFU/mL. In addition, there were highest ratios of mutans to nonmutans bacteria in TYCSB compared to the other media, suggesting high selectivity of this media for mutans species. Conclusion: The results of our study suggest that TYCSB is the most sensitive and selective media for culture of S. mutans for laboratory and clinical studies.