Potential to Use Ultraviolet-Treated Bacteriophages to Control Foodborne Pathogens

Abstract

The use of replication-deficient UV-treated bacteriophages, or phages, presents an alternative to viable phages for food biocontrol applications. Nontransducing UV-treated phages, if used correctly, are unlikely to produce viable progeny phages, which might otherwise mediate undesirable horizontal gene transfer events. Phage T4 and Escherichia coli were used as a model system to examine this possibility. UV-treated phages were able to cause a reduction in the optical density of outer membrane-free cell suspensions and they also killed host cells under conditions not permitting their multiplication, that is, 24 degrees C for 2 h and 37 degrees C for 15 min. Host cell reductions were also demonstrated in broth and on meat at 5 degrees C when high concentrations of phages of 2.3 x 10(9) PFU mL(-1) and 1.8 x 10(8) PFU cm(-2), respectively, were used. At 24 degrees C and 37 degrees C, "lysis from without" was likely to be the mechanism responsible for the reduction in host cell concentrations, but at 5 degrees C this may not have been the case.

Phage Therapy Pharmacology

“…For phages, these values are less useful than for standard antibiotics owing to a combination of the bactericidal nature of phages, their single-hit bacterial killing kinetics, and the phage propensity to replicate upon infection of their bacterial targets, though the latter can be eliminated through genetic or physical phage modification (Goodridge, 2010;Hudson et al, 2010). For phages, these values are less useful than for standard antibiotics owing to a combination of the bactericidal nature of phages, their single-hit bacterial killing kinetics, and the phage propensity to replicate upon infection of their bacterial targets, though the latter can be eliminated through genetic or physical phage modification (Goodridge, 2010;Hudson et al, 2010).…”

Phage Therapy: Eco-Physiological Pharmacology

“…One means is through the genetic engineering of phages so that they are bactericidal but not productive [139]. Alternatively, it is possible to treat phages, such as with ultraviolet radiation, so that again they are bactericidal but not, at least to a degree, capable of producing phage progeny [165]. In addition, phage-like but not replicative bacteriocins may be employed, such as R-type pyocins which are active against Pseudomonas [166, 167] but which also may be engineered to recognize, for example, E. coli O157:H7 [168, 169].…”

“…In addition, phage-like but not replicative bacteriocins may be employed, such as R-type pyocins which are active against Pseudomonas [166, 167] but which also may be engineered to recognize, for example, E. coli O157:H7 [168, 169]. Replication incompetent phages in principle should not be capable of transducing bacterial genes between target bacteria, such as genes encoding bacterial virulence factors [165, 167]. If combined with blocks on phage-induced bacterial lysis, then these efforts also can have the effect of targeting and then killing bacteria but without releasing toxic lysis products.…”

Prevention of bacterial foodborne disease using nanobiotechnology

“…Other ways of harnessing phages to control pathogens include using inactivated particles, immobilizing particles on packaging, or immobilizing phage-encoded lytic proteins (endolysins). Hudson et al100 produced inactive (nonreplicating) phage particles that retained the ability to kill E. coli on meat. The use of inactive phage particles may have advantages for perceived safety or regulatory classification purposes.…”