Abstract
Esculin hydrolysis is a useful test in the differentiation of both gram-positive and gram-negative bacteria covering a wide spectrum of aerobes, facultative anaerobes, and anaerobes. Commonly utilized methods require a minimum of 18 h of incubation in broth or agar medium and utilize the production of a brown-black compound, due to the combination of ferric ions with the hydrolysis product esculetin, as indicator. A procedure is presented that requires 15 to 30 min for completion and utilizes fluorescence loss as the indicator of hydrolysis. Esculin fluoresces at 366 nm, whereas the hydrolysis product esculetin does not. Over 1,400 strains of gram-positive and gram-negative bacteria were tested. There was 98.4% of correlation between the spot test and esculin broth and 97% correlation with the bile-esculin agar.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Facklam R. R. Comparison of several laboratory media for presumptive identification of enterococci and group D streptococci. Appl Microbiol. 1973 Aug;26(2):138–145. doi: 10.1128/am.26.2.138-145.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lindell S. S., Quinn P. Use of bile-esculin agar for rapid differentiation of Enterobacteriaceae. J Clin Microbiol. 1975 May;1(5):440–443. doi: 10.1128/jcm.1.5.440-443.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith P. B., Rhoden D. L., Tomfohrde K. M. Evaluation of the pathotec Rapid I-D system for identification of Enterobacteriaceae. J Clin Microbiol. 1975 Apr;1(4):359–362. doi: 10.1128/jcm.1.4.359-362.1975. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vaughn R. H., Levine M. Differentiation of the "Intermediate" Coli-Like Bacteria. J Bacteriol. 1942 Oct;44(4):487–505. doi: 10.1128/jb.44.4.487-505.1942. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wasilauskas B. L. Preliminary observations on the rapid differentiation of the Klebsiella-Enterobacter-Serratia group on bile-esculin-agar. Appl Microbiol. 1971 Jan;21(1):162–163. doi: 10.1128/am.21.1.162-163.1971. [DOI] [PMC free article] [PubMed] [Google Scholar]