Feces from wild Triatoma dimidiata induces local inflammation and specific immune response in a murine model

In endemic regions for Triatoma dimidiata the vector for Chagas disease, subjects can be in contact with insect`s feces several times through a lifetime. The triatomine’s digestive tract is colonized by diverse but few dominant genera of microorganisms. The immune responses to microbiota feces are poorly known in mammal hosts. The goal of this paper is to describe the local inflammation at the port of inoculation and the humoral immune response in a murine model mimicking natural contamination of feces from wild Triatoma dimidiata and its identification of bacterial community. Feces from twenty T. dimidiata insects captured in peridomestic and domestic ecotopes were used for bacteria isolation and phenotypic identification. Five microliters of whole feces or bacteria isolated colonies were used for intradermal inoculation of mice for detection of humoral immune response and local inflammation at the inoculation site. The bacterial community identified corresponded to Kytococcus, Brevibacillus, Kocuria, Chryseobacterium, Pantoe, Proteus, Burkholderia, Acinetobacter and Stapylococcus. The local inflammation at the inoculation site was dominated by neutrophils infiltration, and specific seric IgG immune response was recognized against whole feces as well as Burkholderia, Acinetobacter and Staphylococcus isolates. In conclusion, feces from T. dimidiata were colonized by few culturable microorganism genera that are able to induce local inflammation and IgG immune response in a murine model.