This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Efthymiou, C. J. Articles by Joseph, S. W. Search for Related Content PubMed Articles by Efthymiou, C. J. Articles by Joseph, S. W. Agricola Articles by Efthymiou, C. J. Articles by Joseph, S. W.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1974 September; 28(3): 411-416
Copyright © 1974 American Society for Microbiology. All Rights Reserved.

Development of a Selective Enterococcus Medium Based on Manganese Ion Deficiency, Sodium Azide, and Alkaline pH

Department of Biology, St. John's University, Jamaica, New York 11439

ABSTRACT

Rogosa broth, without its salt supplement and dissolved in deionized water, was adapted for the selective isolation and enumeration of enterococci. This medium supported good growth of enterococci, but it suppressed growth of other lactic acid bacteria. The sensitivity and specificity of the medium were tested after addition of various increasing concentrations of NaN₃ against known strains of enterococci and other bacteria. Many strains of Streptococcus faecium showed low azide tolerance; optimal growth was obtained at a concentration of 0.01% NaN₃, which totally or partially inhibited unrelated species of lactic acid bacteria. The selectivity of the medium was further increased by pH adjustment to 9.6. Carbonate and Tween 80 were added to overcome partial inhibition of enterococcal growth by the new combination of selective conditions. The final medium was evaluated in agar form in isolations from human and animal feces, polluted water, meat, and dairy products. Counts were obtained after 16 to 17 h of incubation at 37 C. The isolates satisfactorily conformed to the group characteristics of enterococci.