Bacteriophage biocontrol in animals and meat products

Abstract

SummarySince their discovery almost a century ago, bacterial viruses (bacteriophages or ‘phages’) have been used to prevent and treat a multitude of bacterial infections (phage therapy: PT). In addition, they have been the basis for many advances in genetics and biochemistry. Phage therapy was performed on human subjects in the United States, Europe and Asia in the few decades following their discovery. However, Western countries largely abandoned PT in favour of antibiotics in the 1940s. The relatively recent renaissance of PT in the West can be attributed partly to the increasing prevalence of antibiotic resistance in human and animal pathogens. However, the stringent controls on human trials now required in the United States and Europe have led to a greater number of domestic animal and agricultural applications as an alternative to PT in man. This trend is set to continue, at least in the short term, with recent approval from the Food and Drug Administration allowing commercial phage treatments to be used in human food in the USA. Nevertheless, despite these significant milestones and the growing number of successful PT trials, significant obstacles remain to their widespread use in animals, food and ultimately medicine in many parts of the world. This review will provide a brief overview of the history of PT in the West and will summarize some of the key findings of phage biocontrol studies in animals and meat products.

Bacteriophage biocontrol of foodborne pathogens

“…Similar results were found in a human study with E. coli T4 phages that were added to drinking water (Bruttin and Brussow 2005). Individuals with HIV and other immunodeficiency diseases and healthy volunteers have also been intravenously injected with purified phages (e.g., FX174) without any apparent side effects (Atterbury 2009). Indeed, early phage therapy pioneers demonstrated safety by ingesting preparations themselves.…”

Phage Therapy Is Effective in a Mouse Model of Bacterial Equine Keratitis

“…First, because many phages have diverse host ranges, a cocktail of phages could be effective in diverse strains of bacteria. Second, there could be synergism between cocktailed phages (23). Third, the use of mixed phages could prevent the emergence of phage-resistant bacteria (24).…”

“…Indeed, researchers have reported the efficacy of phage therapy for experimental bacterial disease (18)(19)(20)(21)(22). Examples include applications for use of the phages ListShield (Intralytix, Inc., Baltimore, MD) for Listeria monocytogenes and EcoShield (Intralytix) for Escherichia coli O157:H7 to protect against foodborne disease (23,24). In addition, not only phage but also phage endolysin, which is used at the end of the phage lytic cycle, is being assessed for therapeutic use (25).…”

Phages as Therapeutic Tools to Control Major Foodborne Pathogens: Campylobacter and Salmonella

“…Although very different results have been obtained it seems that the proof of principle has been established: phage therapy has potential in the control of foodborne pathogens (Johnson et al, 2008). The large scale, high throughput and mechanization of poultry production and industry, made poultry and products the most commonly used models for phage biocontrol (Atterbury, 2009). This is reflected in the studies that will be addressed below.…”

“…These contradictory results may be a consequence of differences in phage/host combinations, in the matrix used, in the presence of non-host decoys or even in the models applied. Therefore, the efficacy of phage-based biocontrol should be determined on a caseby-case basis (Atterbury, 2009). …”