Glucose-sucrose-potassium tellurite-bacitracin agar, an alternative to mitis salivarius-bacitracin agar for enumeration of Streptococcus mutans.
Abstract
Glucose-sucrose-potassium tellurite-bacitracin agar, an alternative to mitis salivarius-bacitracin agar for enumeration of Streptococcus mutans. J M Tanzer , A C Börjesson , L Laskowski , A B Kurasz and M Testa ABSTRACT 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 revealed GSTB to give significantly higher recoveries than MSB. About 72% of all samples were substantially underestimated for S. mutans with MSB, and 6.7% of samples were falsely negative for S. mutans with MSB. Recovery of background flora on GSTB was as low or lower than on MSB, and both types of agar could be stored for at least 9 weeks without notable change of selectivity. Thus, GSTB agar appears to be simple and reliable to use and requires no anaerobic incubation. Caution is voiced about interpretation of data previously reported which evaluated S. mutans on MSB agar. CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? « Previous | Next Article » Table of Contents This Article J. Clin. Microbiol. October 1984 vol. 20 no. 4 653-659 » Abstract PDF Classifications Research Article Services Email this article to a colleague Similar articles in ASM journals Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of JCM Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Load citing article information Citing articles via Web of Science Citing articles via Google Scholar Google Scholar Articles by Tanzer, J. M. Articles by Testa, M. Search for related content PubMed PubMed citation Articles by Tanzer, J. M. Articles by Testa, M. Related Content Load related web page information Social Bookmarking CiteULike Connotea Delicious Digg Facebook Google+ Mendeley Reddit StumbleUpon Twitter What's this? current issue December 2011, volume 49, issue 12 Alert me to new issues of JCM About JCM Subscribers Authors Reviewers Advertisers Inquiries from the Press Permissions & Commercial Reprints ASM Journals Public Access Policy JCM RSS Feeds 1752 N Street N.W. • Washington DC 20036 202.737.3600 • 202.942.9355 fax • journals@asmusa.org Print ISSN: 0095-1137 Online ISSN: 1098-660X Copyright © 2011 by the American Society for Microbiology. For an alternate route to JCM .asm.org, visit: http://intl- JCM .asm.org | More Info» var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www."); document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E")); var pageTracker = _gat._getTracker("UA-5821458-10"); pageTracker._trackPageview();