Bacterial Microbiome in Wild-Caught Anopheles Mosquitoes in Western Thailand

Abstract

Among the complex microbial community living in the mosquito midgut, some bacteria (e.g., Enterobacter spp.) can deliver effector molecules with anti-Plasmodium effects suppressing the development of malaria parasites (Plasmodium falciparum) before the öokinete can penetrate the mosquito midgut epithelium. Despite knowledge of this phenomenon, only a few studies have defined the diversity of microbiota in wild-caught adult Anopheles species. The objective of this study was to analyze and compare the bacterial microbiota in different Anopheles species, including representatives of the primary malaria vectors in western Thailand. Wild female Anopheles species were sampled from malaria-endemic areas in Tak and Mae Hong Son provinces near the Thai-Myanmar border. Midgut/abdominal bacterial diversity was assessed by examining the 16S rRNA gene, V3 hypervariable region, using PCR-Temporal Temperature Gel Electrophoresis (PCR-TTGE) profiling and sequence analysis. A total of 24 bacterial genera were identified from eight Anopheles species. Five bacterial genera were newly reported in Anopheles mosquitoes (Ferrimonas, Megasphaera, Pectobacterium, Shimwellia, and Trabulsiella). Five genera, including Megasphaera, were detected exclusively in a single-malaria (Plasmodium vivax) infected Anopheles minimus and not observed in other non-infected mosquitoes. The use of PCR-TTGE provides the first characterization of the midgut bacterial microbiome present in wild adult Anopheles in Thailand. Evidence that microbiota might impact pathogen development (suppression) in Anopheles and thereby reduce the risk of pathogen transmission deserves more studies to describe the presence and better understand the biological role of bacteria in natural mosquito populations.

Integration of whole genome sequencing and transcriptomics reveals a complex picture of insecticide resistance in the major malaria vector Anopheles coluzzii

“…Rhizobium , a nitrogen fixing bacteria traditionally associated with plants has not previously been shown to be present in the mosquito microbiome but given the differential abundance within on extraction round, it is unlikely to be a reagent contaminant. Herbaspirillum and Ochrobactrum have previously been reported in the microbiome 46 , but the former has not before been linked to resistance, as seen here. Strikingly, Serratia abundance is dramatically reduced in Banfora-R compared to Banfora-S and is in agreement with a recent discovery in Côte D’Ivoire showing that this bacteria is strongly associated with pyrethroid susceptibility in An.…”

Integration of whole genome sequencing and transcriptomics reveals a complex picture of the reestablishment of insecticide resistance in the major malaria vector Anopheles coluzzii

“…Rhizobium, a nitrogen fixing bacteria traditionally associated with plants has not previously been shown to be present in the mosquito microbiome but given the differential abundance within on extraction round, it is unlikely to be a reagent contaminant. Herbaspirillum and Ochrobactrum have previously been reported in the microbiome [53], but the former has not before been linked to resistance, as seen here. Strikingly, Serratia abundance is dramatically reduced in Banfora-R compared to Banfora-S and is in agreement with a recent discovery in Co ˆte D'Ivoire showing that this bacteria is strongly associated with pyrethroid susceptibility in An.…”

Diversity of midgut microbiota in laboratory-colonized and field-collected Aedes albopictus (Diptera: Culicidae): A preliminary study

“…The diversity of midgut microbiota has been studied and identified from various species of mosquitoes, primarily Anopheles mosquitoes ( Tainchum et al., 2020 ; Zoure et al., 2020 ). In contrast, studies of Aedes and Culex mosquitoes are limited ( Tiawsirisup et al., 2018 ; Muturi et al., 2020 ; Seabourn et al., 2020 ).…”