Comparative Evaluation of a Phage Protein Ligand Assay with VIDAS and BAX Methodology for Detection of Escherichia coli O157:H7 Using a Standard Nonproprietary Enrichment Broth

Escherichia coli O157:H7 is a major foodborne pathogen of concern worldwide. This study was conducted to compare the sensitivity and minimum enrichment time for detection of E. coli O157:H7 by the VIDAS ultraperformance E. coli test (VIDAS ECPT UP) with that of two other commercial detection kits, the ELISA-based VIDAS ECO system and the PCR-based BAX system. Only VIDAS ECPT UP detected all 18 positive results of bacterial suspensions at the level of 10(4) CFU/mL E. coli O157:H7 and 10(6) CFU/mL E. coli as background flora, whereas the BAX system PCR assay detected six positive results and VIDAS ECO detected no positive results. A 6 h enrichment at 42 degrees C is enough for detection of all 18 strains in artificial contaminated raw beef meat, raw milk, and raw chicken, and for detection of most of them in soybean sprout and fresh papaya juice with VIDAS ECPT UP, whereas enrichment of more than 8 h was required for detection of the strains with the VIDAS ECO and PCR-BAX systems. These results indicate that the VIDAS ECPT UP is superior to the other two alternative methods when a standard enrichment broth is used that is different from the broths recommended by the manufacturers.