Detection ofEschericia coliO157:H7 by Fluorescence Polarization Assay and Polymerase Chain Reaction

Abstract

It is recognized that cattle and other domestic animals can be a reservoir of pathogenic Escherichia coli, including serotype O157:H7. To contain this potential health hazard, the first step is the identification of the carrier animals. For these purposes, a rapid serological screening test, a fluorescence polarization assay (FPA) was developed and results obtained from a randomly selected cattle population as well as cattle immunized with E. coli O157:H7 were compared to those obtained with an indirect enzyme immunoassay (IELISA). To identify pathogenic strains in carrier animals, polymerase chain reactions (PCR) for Shiga-like toxins I and II were implemented using agarose electrophoresis. The sensitivity of the fecal extracted E. coli for Shiga-like toxin I and II was approximately 200 CFU per reaction using multiplex hot-start nested PCR. The sensitivity of the fecal extracted E. coli varied from approximately 5x10(2) to 2.5x10(3) CFU per reaction depending on the commercial kits used. The combination of the serological screening FPA and hot-start nested PCR confirmatory assays provided rapid identification of the pathogen.

Bacteriophages Carrying Shiga Toxin Genes: Genomic Variations, Detection and Potential Treatment of Pathogenic Bacteria

“…Improved immunological assays for detection of EHEC, Shiga toxin-converting phages or Shiga toxins are still being developed, especially in combination with other methods, like PCR, the use of electric biochips or cell free translation test [84][85][86][87][88][89][90][91][92][93][94]. Furthermore, improvement of classical methods, based on bacterial cultures, is also considered by some authors as an important advantage in proper identification of EHEC, particularly when used together with molecular tests [95,96].…”

“…Inhibition Inhibition [87] Elevated temperature (over 37 o C) None reported Inhibition [87] Hydrogen peroxide Stimulation None reported [87,88] Starvation Inhibition Inhibition (including impairment of DNA replication) future science group Apart from induction provoked by factors causing the SOS response, induction of Shiga toxinconverting prophages can occur spontaneously. One may assume that it is due to differences in bacterial physiology, rather than differences in the levels of expression of the cI repressor.…”