RP-Department of Biochemistry and Biotechnology

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Browsing RP-Department of Biochemistry and Biotechnology by Subject "16S rRNA gene amplicon sequencing"

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    Western Kenyan Anopheles Gambiae Showing Intense Permethrin Resistance Harbour Distinct Microbiota
    (BioMed Central, 2021) Omoke, Diana; Kipsum, Mathew; Otieno, Samson; Esalimba, Edward; Sheth, Mili; Lenhart, Audrey; Njeru, Ezekiel Mugendi; Ochomo, Eric; Dada, Nsa
    Background: Insecticide resistance poses a growing challenge to malaria vector control in Kenya and around the world. Following evidence of associations between the mosquito microbiota and insecticide resistance, the microbiota of Anopheles gambiae sensu stricto (s.s.) from Tulukuyi village, Bungoma, Kenya, with difering permethrin resistance profles were comparatively characterized. Methods: Using the CDC bottle bioassay, 133 2–3day-old, virgin, non-blood fed female F1 progeny of feld-caught An. gambiae s.s. were exposed to fve times (107.5µg/ml) the discriminating dose of permethrin. Post bioassay, 50 resistant and 50 susceptible mosquitoes were subsequently screened for kdr East and West mutations, and individually processed for microbial analysis using high throughput sequencing targeting the universal bacterial and archaeal 16S rRNA gene. Results: 47% of the samples tested (n=133) were resistant, and of the 100 selected for further processing, 99% were positive for kdr East and 1% for kdr West. Overall, 84 bacterial taxa were detected across all mosquito samples, with 36 of these shared between resistant and susceptible mosquitoes. A total of 20 bacterial taxa were unique to the resistant mosquitoes and 28 were unique to the susceptible mosquitoes. There were signifcant diferences in bacterial composition between resistant and susceptible individuals (PERMANOVA, pseudo-F=2.33, P=0.001), with presence of Sphingobacterium, Lysinibacillus and Streptococcus (all known pyrethroid-degrading taxa), and the radiotolerant Rubrobacter, being signifcantly associated with resistant mosquitoes. On the other hand, the presence of Myxococcus, was signifcantly associated with susceptible mosquitoes. Conclusions: This is the frst report of distinct microbiota in An. gambiae s.s. associated with intense pyrethroid resistance. The fndings highlight diferentially abundant bacterial taxa between resistant and susceptible mosquitoes, and further suggest a microbe-mediated mechanism of insecticide resistance in mosquitoes. These results also indicate fxation of the kdr East mutation in this mosquito population, precluding further analysis of its associations with the mosquito microbiota, but presenting the hypothesis that any microbe-mediated mechanism of insecticide resistance would be likely of a metabolic nature. Overall, this study lays initial groundwork for understanding microbe-mediated mechanisms of insecticide resistance in African mosquito vectors of malaria, and potentially identifying novel microbial markers of insecticide resistance that could supplement existing vector surveillance tools.