Evaluation of test-kits for the detection of Escherichia coli O157 in raw meats and cattle faeces.

Hilda Nyati,Ans Zwartkruis,Caroliene Van Heerwaarden,Annet Heuvelink

doi:10.7455/ijfs/1.2.2012.a3

Hilda Nyati, Ans Zwartkruis + Show 2 more

Open Access

https://doi.org/10.7455/ijfs/1.2.2012.a3

Copy DOI

Abstract

Escherichia coli O157 detection limits in artificially contaminated beef and cattle faeces samples were determined using Dynabeads anti E. coli O157 immunomagnetic beads, VIDAS-UP, VIDAS-ICE, and real-time PCR (GeneDisc and LightCycler) systems. Dynabeads anti-E. coli O157 immunomagnetic separation (IMS) and the GeneDisc cycler were the most sensitive methods, and could detect an initial 1 CFU in 25g beef samples after 6h of incubation in modified tryptone soya broth with novobiocin (mTSB+n) or buffered peptone water (BPW). The VIDAS-UP method could detect an initial 10 CFU, while VIDAS-ICE and the LightCycler methods could only detect an initial 100 CFU. Higher detection rates were achieved with 18 hour incubations, where an initial 1 CFU in a 25g sample could be detected with all five methods. For cattle faeces enrichments, Dynabeads anti-E. coli O157 IMS could detect an initial 1 CFU after a 6 h incubation in mTSB+n, while the VIDAS-UP and VIDAS-ICE methods could detect an initial 10 CFU and both PCR methods could only detect an initial 100 CFU. Detection rates were lower in BPW, compared to mTSB+n, with thresholds of 100 CFU for VIDAS-ICE, VIDAS-UP and GeneDisc methods, and >100 CFU for the LightCycler method.

Highlights

Escherichia coli was for many years considered to be a non-pathogenic inhabitant of human and animal intestinal tracts, and was only recognized as a cause of infantile gastroenteritis in the late 1940s (Smith & Fratamico, 2005; Fratamico, 2006)
Pathogenic strains of Escherichia coli have since emerged as a major cause of documented outbreaks and sporadic cases of diarrhoea world-wide, and are reported by the Centers for Disease Control and Prevention to be one of the three most common food-borne infections (CDC, 2005, 2008)
The objectives of this study were to determine the relative sensitivity and specificity of newly introduced E. coli O157 detection methods, and to assess the applicability of each detection method for routine laboratory use based on labour intensiveness, ease of use and interpretation, cost-effectiveness, and length of time required for results

Summary

Introduction

Escherichia coli was for many years considered to be a non-pathogenic inhabitant of human and animal intestinal tracts, and was only recognized as a cause of infantile gastroenteritis in the late 1940s (Smith & Fratamico, 2005; Fratamico, 2006). Pathogenic strains of Escherichia coli have since emerged as a major cause of documented outbreaks and sporadic cases of diarrhoea world-wide, and are reported by the Cen-. Ters for Disease Control and Prevention to be one of the three most common food-borne infections (CDC, 2005, 2008). Strains of E. coli inducing mild to serious gastrointestinal diseases in humans have been classified into six major categories; enterohaemorrhagic (EHEC), enterotoxigenic (ETEC), enteroinvasive (EIEC), enteroaggregative (EAEC), enteropathogenic (EPEC), and diffusely adherent (DAEC) E. coli. Enterohaemorrhagic E. coli are the most significant group of

Objectives

Methods

Results

Conclusion