Evaluating Recombinant Bacteriophages for Rapid Detection of Escherichia coli O157:H7 in Foods

Author(s): Nathanyelle Soraya Martins de Aquino, Susana de Oliveira Elias, Carolina Fraga Alves, Camila Camargo, Jhuli Aparecida Murineli Baia Fabiola Ayres Cacciatore, Eduardo Cesar Tondo

Escherichia coli O157:H7 is an important foodborne pathogen that is increasingly being isolated around the world. Since this microorganism is the causative agent of haemorrhagic colitis (HC) and fatal haemolyticuremic Syndrome by hemorrhagic colitis (HC) and fatal hemolyticuremic Syndrome (HUS), rapid and accurate detection methods must be available to contribute to food safety. This study evaluates the performance of a recombinant bacteriophage-based assay (PhageDx) forthe detection of E. coli O157:H7 in vitro and across various food matrices. The assay was tested using E. coli O157:H7 strains isolated in Brazil from lettuce irrigation water, bovine carcasses, and hides. The accuracy, sensitivity, and reproducibility of PhageDx were assessed using three inoculum levels (1, 10, and 100 CFU) in ground beef, lettuce, pasteurized milk, and mineral water. PhageDx successfully detected 1 CFU/25 g or mL of E. coli O157:H7 within 7.5 hours, after a 5-hour enrichment step, and detected 100 CFU in just 2.5 hours without enrichment. In analysis of 100 bovine carcasses, PhageDx results were consistent with real-time PCR, with no false positives or negatives. These findings suggest that PhageDx is an effective tool for rapid detection of E. coli O157:H7, supporting its potential application in food safety monitoring.