The gut feeling – phage vs antibiotic therapy

Endangered green turtles, C. mydas, are routinely rehabilitated from bacterial disease using antibiotics, however this can cause long-term gut-related dysbiosis in these herbivores. Ahasan et al. (2019) investigated the ability for phage treatment to eliminate targeted bacteria in captive green turtles. Using 16SrRNA sequencing of bacterial communities in faecal samples, gut microbiome community changes were assessed in turtles either given an oral dose of antibiotic, Acinetobacter venetianus-specific phage cocktail, or a control. Antibiotic and phage treatments significantly lowered the abundance of target Acinetobacter, phage treatment did not permanently alter gut bacterial community composition, unlike the antibiotic.

Ahasan conveys the difficulty in diagnosing disease in C. mydas, it would therefore prove difficult to apply these results to develop phage therapy when the target bacteria are unknown. Additionally, Acinetobacter are not C. mydas pathogens, healthy turtles were used and remained unexposed to a pathogen, so the effect of phage therapy in treating a pathogenic disease in vivo remains unspecified. Despite its flaws, this study demonstrates the ability for phages to eliminate selective bacteria in green turtles, without deleterious effects. Working antibiotics are becoming limited, these results emphasise the potential for phage therapy to replace larger scale antibiotic use such as in aquaculture.

Ahasan, M. S., Kinobe, R., Elliott, L., Owens, L., Scott, J., Picard, J., Huerlimann, R. & Ariel, E. (2019). Bacteriophage versus antibiotic therapy on gut bacterial communities of juvenile green turtle, Chelonia mydas. Environmental microbiology.