Comparative Analysis of Bacterial Communities in Lutzomyia ayacuchensis Populations with Different Vector Competence to Leishmania Parasites in Ecuador and Peru

Abstract

Differences in the gut microbial content of Lutzomyia (Lu.) ayacuchensis, a primary vector of Andean-type cutaneous leishmaniasis in Ecuador and Peru, may influence the susceptibility of these sand flies to infection by Leishmania. As a first step toward addressing this hypothesis, a comparative analysis of bacterial and fungal compositions from Lu. ayacuchensis populations with differential susceptibilities to Leishmania was performed. Bacterial 16S rRNA gene amplification and Illumina MiSeq sequencing approaches were used to characterize the bacterial composition in wild-caught populations from the Andean areas of Ecuador and southern Peru at which the sand fly species transmit Leishmania (Leishmania) mexicana and Leishmania (Viannia) peruviana, respectively, and a population from the northern Peruvian Andes at which the transmission of Leishmania by Lu. ayacuchensis has not been reported. In the present study, 59 genera were identified, 21 of which were widely identified and comprised more than 95% of all bacteria. Of the 21 dominant bacterial genera identified in the sand flies collected, 10 genera had never been detected in field sand flies. The Ecuador and southern Peru populations each comprised individuals of particular genera, while overlap was clearly observed between microbes isolated from different sites, such as the number of soil organisms. Similarly, Corynebacterium and Micrococcus were slightly more dominant bacterial genera in the southern Peru population, while Ochrobactrum was the most frequently isolated from other populations. On the other hand, fungi were only found in the southern Peru population and dominated by the Papiliotrema genus. These results suggest that variation in the insect gut microbiota may be elucidated by the ecological diversity of sand flies in Peru and Ecuador, which may influence susceptibility to Leishmania infection. The present study provides key insights for understanding the role of the microbiota during the course of L. (L.) mexicana and L. (V.) peruviana infections in this important vector.

Overview of paratransgenesis as a strategy to control pathogen transmission by insect vectors

“…There have been many studies on the commensal bacteria in Lutzomyia (e.g. [ 310 – 317 ]), and Phlebotamus (e.g. [ 97 , 318 – 328 ]).…”

Gut Microbiota Dynamics in Natural Populations of Pintomyia evansi under Experimental Infection with Leishmania infantum

“…This hypothesis may be associated with the high parasite infection load in the group of guts treated with the antibiotic cocktail. The microbiota also has a fundamental role in the induction, maturation, and function of the host immune system, modulating host protection from pathogens and infectious diseases [3,24]. Bacteria may also directly inhibit pathogen development, either by hindering the necessary interactions between the pathogen and vector epithelium or through the production of antiparasitic molecules [25], such as antimicrobial peptides (e.g., defensins) [26] and pigment (prodigiosin), mainly through Gram-negative bacteria [27].…”

Current Status of Metatranscriptomic and Related Studies in Hematophagous Disease-Transmitting Vectors

“…Notably, since the development of high throughput platforms, fewer studies have used an NGS approach to analyze the sandfly microbiome compared to other hematophagous arthropods such as mosquitoes and ticks. A few studies have used DNA metabarcoding to describe the bacterial community (e.g., Kelly et al 2017;Papadopoulos et al 2020;Pires et al 2017;Vivero et al 2021Vivero et al , 2019, and the bacterial and fungal communities (Tabbabi et al 2021), and one RNA metabarcoding study analyzed 16S rRNA transcripts (Monteiro et al 2016).…”