Abstract
Detection of lysine decarboxylase activity is a useful supplement to reactions on triple sugar-iron (TSI) and urea agars in the initial examination of suspected pathogenic isolates from fecal cultures. Owing to the added value of motility and indole production in the differentiation of enteric pathogens, we prepared and evaluated a motility-indole-lysine (MIL) medium. The following 890 organisms were tested: 264 Shigella, 2 Edwardsiella, 182 Salmonella enteritidis, 235 S. typhi, 3 Arizona, 32 Yersinia enterocolitica, and 172 other members of the family Enterobacteriaceae. With few exceptions the MIL medium gave the same results as the standard motility, indole, and lysine decarboxylase (Moeller) test media. All discrepancies were with the indole reaction, which was weak in 2 of 67 strains of Escherichia coli and falsely negative in 6 of 32 strains of Y. enterocolitica. When both TSI agar and lysine-iron agar (LIA) slants are used in the evaluation isolates from fecal cultures, detection of H2S is duplicated. Both LIA and MIL medium detect lysine decarboxylase and deaminase activity equally well. Because of its ability to detect motility and indole production, the MIL medium is more useful than LIA when used with TSI agar. The combination of TSI agar, MIL medium, and urea agar enables reliable initial recognition of enteric pathogens of the Enterobacteriaceae.
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.
- Bonev S. I., Zakhariev Z., Gentchev P. Comparative study of media for determination of lysine decarboxylase activity. Appl Microbiol. 1974 Mar;27(3):464–468. doi: 10.1128/am.27.3.464-468.1974. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brooker D. C., Lund M. E., Blazevic D. J. Rapid test for lysine decarboxylase activity in Enterobacteriaceae. Appl Microbiol. 1973 Oct;26(4):622–623. doi: 10.1128/am.26.4.622-623.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- EDWARDS P. R., FIFE M. A. Lysine-iron agar in the detection of Arizona cultures. Appl Microbiol. 1961 Nov;9:478–480. doi: 10.1128/am.9.6.478-480.1961. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ederer G. M., Clark M. Motility-indole-ornithine medium. Appl Microbiol. 1970 Nov;20(5):849–850. doi: 10.1128/am.20.5.849-850.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ewing W. H., Ball M. M., Bartes S. F., McWhorter A. C. The biochemical reactions of certain species and bioserotypes of Salmonella. J Infect Dis. 1970 Mar;121(3):288–294. doi: 10.1093/infdis/121.3.288. [DOI] [PubMed] [Google Scholar]
- Ewing W. H., Wilfert J. N., Kunz L. J., Dumoff M., Isenberg H. D. How far to go with Enterobacteriaceae? J Infect Dis. 1969 Feb;119(2):197–213. doi: 10.1093/infdis/119.2.197. [DOI] [PubMed] [Google Scholar]
- FALKOW S. Activity of lysine decarboxlase as an aid in the identification of Salmonellae and Shigellae. Am J Clin Pathol. 1958 Jun;29(6):598–600. doi: 10.1093/ajcp/29.6_ts.598. [DOI] [PubMed] [Google Scholar]
- GILLIES R. R. An evaluation of two composite media for preliminary identification of Shigella and Salmonella. J Clin Pathol. 1956 Nov;9(4):368–371. doi: 10.1136/jcp.9.4.368. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johnson J. G., Kunz L. J., Barron W., Ewing W. H. Biochemical differentiation of the Enterobacteriaceae with the aid of lysine-iron-agar. Appl Microbiol. 1966 Mar;14(2):212–217. doi: 10.1128/am.14.2.212-217.1966. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jordan G. W., Hadley W. K. Human infection with Edwardsiella tarda. Ann Intern Med. 1969 Feb;70(2):283–288. doi: 10.7326/0003-4819-70-2-283. [DOI] [PubMed] [Google Scholar]
- King S., Metzger W. I. A new plating medium for the isolation of enteric pathogens. I. hektoen enteric agar. Appl Microbiol. 1968 Apr;16(4):577–578. doi: 10.1128/am.16.4.577-578.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- King S., Metzger W. I. A new plating medium for the isolation of enteric pathogens. II. Comparison of hektoen enteric agar with SS and EMB agar. Appl Microbiol. 1968 Apr;16(4):579–581. doi: 10.1128/am.16.4.579-581.1968. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee Y. H., Daly A. K., Thurston P. Three-tube method for screening stool cultures for Salmonella and Shigella. Appl Microbiol. 1972 Sep;24(3):409–411. doi: 10.1128/am.24.3.409-411.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MARCUS S., GREAVES C. Danger of false results using screw-capped tubes in diagnostic bacteriology. J Lab Clin Med. 1950 Jul;36(1):134–136. [PubMed] [Google Scholar]