Microbiota diversity of Anopheles gambiae in Bankeng, southern Cameroon, and its association with Plasmodium falciparum infection

Malaria control requires the coordination of different strategies due to the lack of an effective vaccine and the emerging resistance of parasites to drugs and of vectors to insecticides. Therefore, efficient and environmentally safe alternative control strategies are still needed. In this study, we explored the composition of microbiota of the Anopheles gambiae and its variability in the presence of natural Plasmodium infection during the wet and dry seasons, in order to determine their potential as a novel vector control-based approach to fight malaria. An entomological survey of a collection of An. gambiae was conducted in Bankeng. Using 16S ribosomal RNA amplicon-based sequencing, we investigated the bacterial microbiota of mosquitoes naturally infected or uninfected with Plasmodium falciparum. A total of 120 mosquitoes were selected randomly corresponding to 60 mosquitoes per infection status. Overall, 99 bacterial taxa were detected across all the samples, with 97 of these shared between uninfected and infected. A total of two were unique to uninfected (Acetobacteraceae, Enterococcus), while no bacteria were unique to infected mosquitoes. However, there were significant differences in bacterial composition between both groups. Additionally, differential abundance revealed notable variations in microbiota composition, with 14 bacterial genera more abundant in uninfected mosquitoes and only two bacterial genera more abundant in the infected mosquitoes. Observed amplicon sequence variants and Shannon indices revealed a significant difference in bacterial diversity between infected (positive) and uninfected (negative) An. gambiae with higher diversity observed in negative samples during the wet season and in positive samples during the dry season. These findings highlight potential associations between certain bacterial taxa and infection status, suggesting they may be linked to susceptibility or resistance, although causality cannot be determined from this study. Ultimately, this baseline information provides a foundation for studies on the functions and interactions of the microbiota in natural populations of Anopheles gambiae and their susceptibility to natural Plasmodium infection.IMPORTANCEMalaria control faces challenges due to the absence of an effective vaccine and growing resistance to drugs and insecticides, highlighting the need for alternative strategies. This study investigates the microbiota composition of Anopheles gambiae mosquitoes in Bankeng, Cameroon, and its association with natural Plasmodium falciparum infection. Using 16S rRNA amplicon sequencing, the bacterial communities of 120 mosquitoes-60 infected and 60 uninfected-were analyzed. A total of 99 bacterial taxa were identified, with 97 shared between both groups. Only two taxa (Acetobacteraceae and Enterococcus) were exclusive to uninfected mosquitoes, and none were unique to the infected group. Significant differences in microbiota composition were observed: 14 bacterial genera were more abundant in uninfected mosquitoes, while only two were enriched in infected ones. These findings suggest that specific bacteria may influence susceptibility to Plasmodium infection. This study provides foundational knowledge for exploring microbiota-based or paratransgenic strategies in malaria vector control.