Impacts of Antibiotic and Bacteriophage Treatments on the Gut-Symbiont-Associated Blissus insularis (Hemiptera: Blissidae)

Abstract

The Southern chinch bug, Blissus insularis, possesses specialized midgut crypts that harbor dense populations of the exocellular symbiont Burkholderia. Oral administration of antibiotics suppressed the gut symbionts in B. insularis and negatively impacted insect host fitness, as reflected by retarded development, smaller body size, and higher susceptibility to an insecticide, bifenthrin. Considering that the antibiotics probably had non-lethal but toxic effects on host fitness, attempts were conducted to reduce gut symbionts using bacteriophage treatment. Soil-lytic phages active against the cultures of specific Burkholderia ribotypes were successfully isolated using a soil enrichment protocol. Characterization of the BiBurk16MC_R phage determined its specificity to the Bi16MC_R_vitro ribotype and placed it within the family Podoviridae. Oral administration of phages to fifth-instar B. insularis, inoculated with Bi16MC_R_vitro as neonates had no deleterious effects on host fitness. However, the ingested phages failed to impact the crypt-associated Burkholderia. The observed inactivity of the phage was likely due to the blockage of the connection between the anterior and posterior midgut regions. These findings suggest that the initial colonization by Burkholderia programs the ontogeny of the midgut, providing a sheltered residence protected from microbial antagonists.

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

“…However, Xu et al . () reported that the oral administration of Burkholderia ‐specific phages was unable to eliminate the crypt‐associated Burkholderia in the southern chinch bug ( Blissus insularis ). The observed inactivity of these phages in the southern chinch bug was attributed to the anatomical limitation such as blockage of the connection between the anterior and posterior mid‐gut regions, which is uncommon in green turtles.…”

“…In addition, the effective elimination of the targeted pathogenic bacteria from the gastrointestinal tract has also been demonstrated in several phage therapy experiments in both humans and animals (Sulakvelidze and Barrow, 2005). However, Xu et al (2016) reported that the oral administration of Burkholderia-specific phages was unable to eliminate the crypt-associated Burkholderia in the southern chinch bug (Blissus insularis). The observed inactivity of these phages in the southern chinch bug was attributed to the anatomical limitation such as blockage of the connection between the anterior and posterior mid-gut regions, which is uncommon in green turtles.…”

The influence of antibiotics on gut bacteria diversity associated with laboratory-reared Bactrocera dorsalis

“…This method is advantageous in that it makes the in vivo uncovering of gut bacteria possible, especially for some uncultivable bacteria (Li et al ., 2017; Myint Khaing et al ., 2017). However, the non-lethal and toxic levels of antibiotics can influence the result (Xu et al ., 2016). Teasing out the influence of antibiotics themselves on host insects becomes a key question.…”

We and herbivores eat endophytes

“…When an herbivore has recently ingested an endophyte, gut strains would be identical or very similar to the plant isolates, as can be observed in phylogenies from Weissella from panda faeces, in L. plantarum and clostridia phylogenies (Fig. 2) or in burkholderias from the stinkbugs (Itoh et al, 2014;Tago et al, 2015;Xu et al, 2016b). On the other hand, when the endophytes coevolved with their animal hosts which maintain them by vertical transfer, then these bacteria would be divergent from plant bacteria, as observed in some insect symbionts such as Commensalibacter and Dactylopiibacterium (Serv ın-Garcidueñas et al, 2014; Vera-Ponce de Le on et al, 2017).…”