Bacteriophage versus antibiotic therapy on gut bacterial communities of juvenile green turtle, Chelonia mydas

Abstract

Summary Green turtles are endangered marine herbivorous hindgut fermenters that contribute to a variety of marine ecosystems. Debilitated turtles are often rehabilitated in turtle hospitals. Since accurate diagnosis of disease is difficult, broad‐spectrum antibiotics are routinely used as a general treatment, potentially causing collateral damage to the gut microbiome of the patient. Here, we evaluated the concept of the application of bacteriophage (phages) to eliminate targeted intestinal bacteria as an alternative to a broad‐spectrum antibiotic (enrofloxacin) in clinically healthy, captive green turtles. Additionally, the impact of a broad‐spectrum antibiotic (enrofloxacin) and phage therapy on the gut bacterial communities of green turtles was evaluated. Gut bacterial communities in faecal samples were analysed by sequencing the V1‐V3 regions of the bacterial 16S rRNA. Bacteria‐specific phage cocktails significantly (P < 0.05) reduced targeted Acinetobacter in phage‐treated turtles during the therapy. Compared to control, no significant difference was observed in the bacterial diversity and compositions in phage‐treated turtles. In contrast, bacterial diversity was significantly (P < 0.05) reduced in antibiotic‐treated turtles at day 15 and throughout the trial. The alteration in the bacterial microbiota of antibiotic‐treated turtles was largely due to an increase in abundance of Gram‐positive Firmicutes and a concurrent decrease in Gram‐negative Bacteroidetes, Proteobacteria and Verrucomicrobia. Additionally, we observed the relative abundance of several bacteria at lower taxonomic level was much less affected by phages than by antibiotics. These data offer the proof of concept of phage therapy to manipulate transient as well as indigenous bacterial flora in gut‐related dysbiosis of turtles.

Exploring the effect of plant substrates on bacterial community structure in termite fungus-combs

“…This is consistent with Schauer et al [84] who described that a high-fiber diet caused shifts in the diversity of dominant gut bacteria in cockroach. Furthermore, the discriminatory genus in Peptostreptococcaceae, Peptoclostridium, has the ability to breakdown and utilize plant fibers [85,86]. In bottom combs, the families of Proteobacteria also presented different preferences to different diets.…”

Microbiome diversity and composition varies across body areas in a freshwater turtle

“…Few studies have examined turtle microbiomes, and, as often is the case in turtle research, the literature is taxonomically biased, with most studies focusing on sea turtles [27–34] and their eggs [35–39], followed by tortoises [40–45]. These groups are certainly important and more studies should be conducted on them (particularly expanding the number of species covered), but these taxonomic groups are highly ecologically divergent from most turtle species, and they only represent three turtle families and 20 % of extant species [9].…”

The Use of Bacteriophages and Immunological Monitoring for the Treatment of a Case of Chronic Septicemic Cutaneous Ulcerative Disease in a Loggerhead Sea Turtle Caretta caretta

“…Phages have been used successfully in humans (Kutter 2008;Pirnay et al 2011) and other animal species, including a report of phages being used to treat gut-related dysbiosis in green sea turtles Chelonia mydas (Ahasan et al 2020). In the sea turtle study, phage therapy and TABLE 2.…”

“… 2011 ) and other animal species, including a report of phages being used to treat gut‐related dysbiosis in green sea turtles Chelonia mydas (Ahasan et al. 2020 ). In the sea turtle study, phage therapy and antimicrobial treatment with enrofloxacin were compared, resulting in a reduction of the target bacteria population in both treatment groups.…”

“…There was no change in gut bacterial communities in the phage‐treated turtles compared to controls, but there was a significant decrease in the other bacterial communities in turtles treated with enrofloxacin (Ahasan et al. 2020 ). To our knowledge, the present study is the first report of using phages to treat SCUD in a sea turtle, which healed faster and more completely from this treatment than with previous treatments.…”