Glucose-sucrose-potassium tellurite-bacitracin agar, an alternative to mitis salivarius-bacitracin agar for enumeration of Streptococcus mutans

作者：Jason M. Tanzer, A C Börjesson, Leonard F. Laskowski, A B Kurasz, M Testa · 发表于：Journal of Clinical Microbiology · 年份：1984 · DOI：10.1128/jcm.20.4.653-659.1984 · 被引用次数：57 · 研究领域：Streptococcal Infections and Treatments、Oral microbiology and periodontitis research、Plant-based Medicinal Research

An agar medium for selective recovery and enumeration of Streptococcus mutans was developed as an alternative to mitis salivarius-bacitracin (MSB) agar. Combinations of dyes, antibiotics, and tellurite were added to a nonselective medium which, because of its sucrose content, allowed easy recognition of S. mutans colonies. Candle jar incubation for 2 days, by comparison with anaerobic incubation, reduced background flora but did not diminish S. mutans recoveries from clinical samples. Quantitative comparisons were made of the simultaneous recoveries of a number of authentic S. mutans serotype representatives and fresh clinical isolates, using various glucose-sucrose-potassium tellurite-bacitracin (GSTB) formulations and mitis salivarius, MSB, and blood agars. Mitis salivarius counts were not detectably different from blood counts, but counts on MSB were distinctly lower. A formulation of the new medium containing 5% glucose 5% sucrose, 0.001% potassium tellurite, 0.3 U of bacitracin per ml (hence GSTB), and 2% agar gave recoveries nearly equal to those on mitis salivarius agar and much greater than those on MSB. The medium yielded readily recognized S. mutans colonies and facilitated detection of intracellular polysaccharide formers upon flooding with I2 reagent. Freshly isolated serotype c, E, and f colonies could often be distinguished from serotype d and g colonies, a distinction made reliable by testing for intracellular polysaccharide. A study of 300 salivary samples rev...