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

<span style="font-family: Times New Roman; font-size: small;"> </span><p class="MsoNormal" style="margin: 0in 0in 10pt; text-align: justify; line-height: 150%;"><span style="font-size: small;"><span style="font-family: Calibri;"><span style="mso-bidi-font-style: normal;"><span style="mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><em>Escherichia coli</em> O157 detection limits in artificially contaminated beef and cattle faeces samples were determined using Dynabeads anti <em>E. coli</em> O157 immunomagnetic beads, VIDAS-UP, VIDAS-ICE, and real-time PCR (GeneDisc and LightCycler) systems. Dynabeads anti-<em>E. coli</em> 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-<em>E. coli </em>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 &gt;100 CFU for the LightCycler method.</span></span><span style="mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;"><!--?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /--></span></span></span></p><span style="font-family: Times New Roman; font-size: small;">