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Proceedings Paper

Application of horse-radish peroxidase linked chemiluminescence to determine the production mechanism of Shiga-like toxins by E. coli O157:H7
Author(s): Shu-I Tu; Joseph Uknalis; Andrew Gehring; Yiping He
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Paper Abstract

A sandwiched immunoassay consisting of toxin capture by immunomagnetic beads (IMB) and toxin detection by horseradish peroxidase (HRP) linked chemiluminescence was used to follow the production of Shiga-like toxins (SLT) by E. coli O157:H7. The intensity of luminescence generated by the oxidation of luminol-liked compounds was used to represent the concentration of toxins produced. The time-course of SLT production by E. coli O157:H7 under different conditions was investigated. In pure culture, optimal generation of SLT showed a significant delay than the steady state of cell growth. In mixed cultures of SLT producing E. coli O157:H7 and non-SLT producing E. coli K-12 strain, the production of toxins was substantially decreased. However, the growth of E. coli O157:H7 was not affected by the presence of K-12 strain. This decrease in SLT production was also observed in radiation-sterile ground beef. In regular ground beef that might contain numerous other bacteria, the growth of E. coli O157:H7 in EC media was not significantly affected but the lowered production of SLT was observed. The results showed that mechanism of inducing SLT production was complex with both the growth time and growth environment could influence SLT production. The addition of homo-serine lactone to the growth media enhanced the production of SLT. Thus, possibly cell-cell communication may have a role in SLT production by E. coli O157:H7.

Paper Details

Date Published: 12 October 2007
PDF: 9 pages
Proc. SPIE 6761, Optics for Natural Resources, Agriculture, and Foods II, 67610C (12 October 2007); doi: 10.1117/12.747453
Show Author Affiliations
Shu-I Tu, USDA Agricultural Research Service (United States)
Joseph Uknalis, USDA Agricultural Research Service (United States)
Andrew Gehring, USDA Agricultural Research Service (United States)
Yiping He, USDA Agricultural Research Service (United States)


Published in SPIE Proceedings Vol. 6761:
Optics for Natural Resources, Agriculture, and Foods II
Yud-Ren Chen; George E. Meyer; Shu-I Tu, Editor(s)

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