Cultivable Bacterial Diversity in the Gut of the Chagas Disease Vector Triatoma dimidiata: Identification of Possible Bacterial Candidates for a Paratransgenesis Approach

Abstract

Since bacterial symbionts play a vital role in the metabolism of hematophagous insect vectors the method known as paratrangenesis, which consists of the use of cultivable insect symbionts to interfere with the transmission of vector-transmitted pathogens has been shown to be effective in certain vector control oriented studies. In Chagas disease research a recent study introduced transgenes through a parastransgenic approach and prevented the development of a vector species for this disease. However this approach requires a previous characterization of the bacterial symbionts present in the species vector of interest, since a selection of the cultivable bacterial symbiont used is mandatory. In this study, we describe the gut bacterial diversity of Triatoma dimidiata specimens from Southern Mexico. Bacteria from both wild and laboratory-reared specimens were cultured, and resulting colonies were grown individually, harvested, and subsequently identified by 16S ribosomal loci sequencing. A total of five and three genera and a total of nine and six bacterial species were identified from field captured and laboratory reared Triatoma dimidiata specimens respectively. A majority of Gram positive bacteria were identified, which included the genera Staphylococcus, Bacillus, Brevibacterium, Micrococcus, and Delftia. Given previous studies we propose the use of Staphylococcus saprophyticus, Micrococcus luteus, and Bacillus megaterium as potential candidates for future paratransgenic efforts done with Triatoma dimidiata, which is one of the most important vectors of Chagas disease, in Central and South America. Given the vital association bacterial symbionts play in the metabolism of routes of hematophagous insect vectors Paratransgenesis consists of the use of cultivable insect symbionts to interfere with the transmission of vector-transmitted pathogens.

Ontogeny, species identity, and environment dominate microbiome dynamics in wild populations of kissing bugs (Triatominae)

“…Previous studies on triatomine microbiomes have suggested various factors, including ontogeny [48,51], species identity [41,47,50,51,108], sex [44,50], blood meal source [44], and T. cruzi infection [24,43,45,49,50], as determinants of microbiome composition, while another study claimed triatomine microbiomes have no determining factor [40]. Since many were based on limited sample size (e.g., N = 4 in [40], N = 14 in [44], N = 20 in [42], N = 9 in [41], N = 29 in [51]) and largely fragmented by host taxonomy, ontogeny, geographic origin, T. cruzi infection status, or were restricted to colony-reared bugs, it is difficult to draw comparative conclusions. We thus paid particular attention to our sampling design and molecular approach, ensuring that our study enabled multiple comparisons at different scales (i.e., different species from the same locality, different species from the same microhabitat, and different localities for the same species) across all ontogenetic stages.…”

“…In triatomines, thirteen high throughput sequencing studies published since 2015 have indicated a wide range of factors that potentially influence their microbiomes. However, it remains difficult to derive any consistent cross-species patterns since the studies utilised a wide variety of DNA templates, including pooled or individual bodies, entire abdomens, the distal part of the abdomen, whole guts, midguts, faeces, and cultured bacterial colonies [40][41][42][43][44][45][46][47][48][49][50][51][52], and were often further complicated by other variables (e.g., sex, locality, instar, T. cruzi infection status). Apart from these methodological differences, the disparity among studies could also reflect true biological characteristics of Triatominae.…”

Ontogeny, species identity and environment dominate microbiome dynamics in wild populations of kissing bugs (Triatominae)

“…Since many were based on limited sample size (e.g. N=4 in [33]; N=14 in [34]; N=20 in [37]; N=9 in [36]; N=29 in [42]) and largely fragmented by host taxonomy, ontogeny, geographic origin, T. cruzi infection status, restricted to colony-reared bugs, and employed different molecular methods, it is difficult to draw comparative conclusions. We thus paid particular attention to our sampling design and molecular approach, ensuring that our study enabled multiple comparisons at different scales (i.e.…”

“…Since 2015, twelve studies have investigated triatomine microbiomes using next-generation sequencing (NGS) tools. Unfortunately, the data lacks methodological consistency, having been retrieved from a wide variety of DNA templates, including pooled or individual bodies, entire abdomens, the distal part of the abdomen, whole guts, midguts, faeces, and cultured bacterial colonies [33][34][35][36][37][38][39][40][41][42][43][44], and often further complicated by other variables (e.g. sex, locality, instar, T. cruzi infection status).…”

Changes in Bacterial Diversity, Composition and Interactions During the Development of the Seabird Tick Ornithodoros maritimus (Argasidae)

“…Although previously reported in ticks [3 9, 93-95], the genus Brevibacterium is poorly known. Brevibacterium species occurring in haematophagous arthropods (kissing bugs, sand flies and horn flies) have been simply described as non-pathogenic bacteria with low abundance [96][97][98]. However, the recurrent presence of Brevibacterium in diverse unrelated haematophagous arthropods suggests that these bacteria may play a role in blood digestion by their arthropod hosts, and thus possibly in ticks.…”