Exploration of the Cuticular and Intestinal Microbiota of Pyrethroid-Resistant Anopheles gambiae at Tokpa-Zougo in the Commune of Abomey-Calavi in Southern Benin

Background: Mosquito microbiota have recently been identified as one of the multiple mechanisms underlying insecticide resistance. The aim of this study was therefore to assess the cuticular and intestinal microbial diversity of Anopheles mosquitoes exposed or not to pyrethroids (deltamethrin and permethrin) at Tokpa-Zoungo in the commune of Abomey-Calavi in southern Benin. Methodology: The Anopheles larvae collected in Tokpa-zoungo were transported to the Entomological Research Center of Cotonou where insecticide susceptibility tests and molecular identification on the adult mosquitoes aged 2 to 5 days were carried out. The microbiological analyses were carried out in three steps: the preparation of the mother suspensions of the mosquito microbiota, the culture and isolation on the EMB, MSA and PDA agars and the identification and conservation of the isolated microbial strains. Results: The species Anopheles coluzzii was predominant (62%), with high resistance to pyrethroids. Microbiological analysis revealed that species of the Enterobacteriales family (71.11%) were the most represented. Differences were also noted between the microbial species identified in terms of microbiota and resistance phenotype. Yeasts appeared only on the cuticle surface of Kisumu, and wild strains were not exposed to insecticides. Susceptible mosquitoes had lower intestinal microbial diversity than deltamethrin- and permethrin-resistant mosquitoes and wild strains not exposed to insecticides. Conclusion: The study showed a variation in microbial communities carried by Anopheles coluzzii according to microbiota type and resistance phenotype. But these differences do not allow us to define a microbial identity specific to a given resistance phenotype. Further research is needed to better understand insecticide-microbiota interactions.