What, how, and why? - anti-EHEC phages and their application potential in medicine and food industry

Abstract

Enterohemorrhagic Escherichia coli (EHEC) are pathogens that, only in the United States, cause more than 250,000 foodborne infections a year. Since antibiotics or other antidiarrheal agents may increase the hemolytic-uremic syndrome (HUS) development risk, currently only supportive therapy, including hydration, is used. Therefore, many methods to fight EHEC bacteria focus on their use in food processing to prevent human infection. One of the proposed anti-EHEC agents is bacteriophages, known for their bactericidal effect, host specificity, and lack of cross-resistance with antibiotics. In this review article, we provide an overview of the characteristics like source of isolation, morphology, kinetics of life cycle, and treatment potential of over 130 bacteriophages able to infect EHEC strains. Based on the reviewed literature, we conclude that bacteriophages may play a highly significant role in regulating EHEC propagation. In addition, we also point out the phage features that should be taken into account not only when using bacteriophages but also when examining their properties. This may contribute to accelerating the pace of work on the preventive use of bacteriophages, which is extremely needed in the modern world of the food industry, but also stimulate interest in phages and accelerate regulatory work that would enable the use of bacteriophages also in medicine, to fight the drug-resistant strains.

Keywords: Bacteriophages; EHEC; Food; Phage therapy.

Fig. 1

Main sources used for isolation of phages infecting EHEC

Fig. 2

Diagram of the phage development cycles: lytic (A) and lysogenic (B). Numbers indicate different possible effects of prophage presence: 1—Production of virulence factors like toxins and biofilm inducers; 2—Superinfection resistance through receptor blocking, abortive infection and assembly disruption; 3—Resistance to antimicrobials due to the production of inactivating enzymes and efflux pumps promotion; 4 – Horizontal gene transfer

Fig. 3

Main risk factors of food contamination with EHEC in industry