Phage applications for biocontrol of enterohemorrhagic E. coli O157:H7 and other Shiga toxin-producing Escherichia coli

Foodborne outbreaks are becoming increasingly common and linked to zoonotic diseases caused by microbial spillover from wild or farm animals. Furthermore, agricultural animals could be considered reservoirs of multidrug-resistant (MDR) microorganisms. Escherichia coli O157:H7, a widespread foodborne pathogen, poses a substantial hazard due to its ubiquitous environmental distribution, MDR phenotypes, and life-threatening pathogenicity. This bacterium produces a potent toxin (Shiga toxin, Stx) encoded by prophages (Stx-phage). In addition to antibiotic resistance, E. coli O157:H7 has been shown to express more Stx upon treatment with antibiotics such as trimethoprim-sulfamethoxazole and metronidazole than controls. The combination of MDR and increased pathogenicity upon antibiotic treatment requires the development of alternatives for treating and preventing E. coli O157:H7 and related bacteria. Bacterial viruses (phages) are gaining popularity in clinical and veterinary settings due to their high antibacterial activities and lack of side effects in animals. Phage application in food production can help reduce the spread of E. coli O157:H7 and other Stx-producing E. coli (STEC), thus decreasing the burden of infection and economic loss due to these foodborne zoonoses. The present review will provide an update on phage utilization in the food industry to reduce the STEC load, with particular focus on O157:H7.