Efficacy of phage therapy in poultry: a systematic review and meta-analysis

The increasing prevalence of antimicro-bial resistant bacteria has sparked a renewed interest in alternative bacterial control methods, including bacterio-phage administration. In order to determine the overall efficacy of bacteriophage administration for the reduc-tion of bacterial concentrations in poultry, a systematic literature review and a meta-analysis were conducted. The systematic review included studies in which 1) live chickens were challenged with a known quantity of bac-teria; and 2) challenged chickens were administered a known quantity of bacteriophages; and 3) concentrations of the challenge bacteria were measured in tissue/fluid samples from both challenged and unchallenged chickens after phage administration; and 4) either standard devia-tion or standard error was reported. Results of a meta -analysis of the 12 studies included in this review (total inputs: n = 41; total observations: n = 711) indicated that concentrations of challenge bacteria were signifi-cantly lower (P < 0.001) in challenged, phage-treated chickens than in challenged, untreated chickens (effect size =-0.82 log10 cfu/g). Phage treatment effects were significantly greater (P < 0.01) in chickens administered phages via feed than in chickens administered phages via drinking water or aerosol spray. No significant differen-ces were observed between subgroups when data were disaggregated by various other experimental characteris-tics, though some significant differences were observed across subgroups after further disaggregation by sam-pling time and animal age. As a whole, findings from the systematic review and meta-analysis indicate that phage administration can significantly lower concentrations of targeted bacteria in chickens and that, in some instances, the effect may be greater in the short-term vs. the long-term and in older vs. younger chickens.

Automated summary

The systematic review and meta-analysis showed that bacteriophage administration can significantly reduce bacterial concentrations in chickens. Short-term effects may be more pronounced than long-term effects, and older chickens may benefit more than younger chickens.