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. 1973 Aug;26(2):138–145. doi: 10.1128/am.26.2.138-145.1973

Comparison of Several Laboratory Media for Presumptive Identification of Enterococci and Group D Streptococci

R R Facklam 1
PMCID: PMC379740  PMID: 4490481

Abstract

Bile-esculin (Difco), modified bile-esculin (Difco), selective enterococcus (Pfizer Co.), and eosin-methylene blue agar media were evaluated for accuracy in identifying group D streptococci. The regular and modified bile-esculin media performed equally well, but the selective enterococcus and eosin-methylene blue agars did not accurately differentiate the group D from non-group D streptococci. A modified 6.5% NaCl broth was compared with unmodified 6.5% NaCl broth and Streptococcus faecalis (SF; Difco) broth for accuracy in differentiating enterococci from non-enterococci. The modified and unmodified broths worked equally well in the salt tolerance test, but the lot-to-lot variability of SF broth made this medium unusable as an indicator for enterococci. With all seven media, the number of strains giving positive tests decreased when the tests were incubated at 45 C as compared with 35 C, and the number of strains giving negative tests increased. Thus, the number of false-positive identifications decreased, but the number of false-negative identifications increased. Variability in the susceptibility of group D non-enterococcal streptococci to oxacillin and methicillin sensitivity disks limited the usefulness of these tests for presumptive identification of either enterococci or group D streptococci.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Braunstein H., Tucker E. B., Gibson B. C. Identification and significance of Streptococcus agalactiae (Lancefield group B). Am J Clin Pathol. 1969 Feb;51(2):207–213. doi: 10.1093/ajcp/51.2.207. [DOI] [PubMed] [Google Scholar]
  2. Facklam R. R., Moody M. D. Presumptive identification of group D streptococci: the bile-esculin test. Appl Microbiol. 1970 Aug;20(2):245–250. doi: 10.1128/am.20.2.245-250.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Facklam R. R. Recognition of group D streptococcal species of human origin by biochemical and physiological tests. Appl Microbiol. 1972 Jun;23(6):1131–1139. doi: 10.1128/am.23.6.1131-1139.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Hajna A. A., Perry C. A. Comparative Study of Presumptive and Confirmative Media for Bacteria of the Coliform Group and for Fecal Streptococci. Am J Public Health Nations Health. 1943 May;33(5):550–556. doi: 10.2105/ajph.33.5.550. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Isenberg H. D., Goldberg D., Sampson J. Laboratory studies with a selective Enterococcus medium. Appl Microbiol. 1970 Sep;20(3):433–436. doi: 10.1128/am.20.3.433-436.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. LORIAN V., ZANON U. DISC TEST FOR DIFFERENTIATION OF ENTEROCOCCI. J Bacteriol. 1963 Nov;86:1117–1117. doi: 10.1128/jb.86.5.1117-1117.1963. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Lee W. S. Improved procedure for identification of group D enterococci with two new media. Appl Microbiol. 1972 Jul;24(1):1–3. doi: 10.1128/am.24.1.1-3.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Pavlova M. T., Brezenski F. T., Litsky W. Evaluation of various media for isolation, enumeration and identification of fecal streptococci from natural sources. Health Lab Sci. 1972 Oct;9(4):289–298. [PubMed] [Google Scholar]
  9. SWAN A. The use of a bile-aesculin medium and of Maxted's technique of Lancefield grouping in the identification of enterococci (group D streptococci). J Clin Pathol. 1954 May;7(2):160–163. doi: 10.1136/jcp.7.2.160. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Sabbaj J., Sutter V. L., Finegold S. M. Comparison of selective media for isolation of presumptive group D streptococci from human feces. Appl Microbiol. 1971 Dec;22(6):1008–1011. doi: 10.1128/am.22.6.1008-1011.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Toala P., McDonald A., Wilcox C., Finland M. Susceptibility of group D streptococcus (enterococcus) to 21 antibiotics in vitro, with special reference to species differences. Am J Med Sci. 1969 Dec;258(6):416–430. doi: 10.1097/00000441-196912000-00006. [DOI] [PubMed] [Google Scholar]
  12. von Graevenitz A., Redys J. J., Cassidy E. Evaluation of a new differential test for enterococci in the clinical laboratory. J Med Microbiol. 1970 May;3(2):227–231. doi: 10.1099/00222615-3-2-227. [DOI] [PubMed] [Google Scholar]

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