Ingestion of amoxicillin-clavulanic acid at therapeutic concentration during blood meal impacts Aedes aegypti microbiota and dengue virus transmission

Abstract

Dengue virus (DENV), mainly transmitted by Aedes aegypti mosquitoes, is the most prevalent arbovirus worldwide, representing a public health problem in tropical and subtropical countries. In these areas, antibiotic consumption rises which may impact both mosquito microbiota and dengue transmission. Here, we assessed how the ingestion by Ae. aegypti of therapeutic concentrations of amoxicillin-clavulanic Acid association (Amox/Clav), a broad-spectrum antibiotic used to treat febrile symptoms worldwide, impacted its microbiota. We also evaluated whether simultaneous ingestion of antibiotic and DENV impacted Ae. aegypti ability to transmit this virus. We found that Amox/Clav ingestion impacted microbiota composition in Ae. aegypti and we confirmed such impact in field-collected mosquitoes. Furthermore, we observed that Amox/Clav ingestion enhanced DENV dissemination and transmission by this mosquito at 21 days post-DENV exposure. These findings increase our understanding of factors linked to human hosts that may influence dengue transmission dynamics in regions with mass-drug administration programs.

Figure 1

Experimental design for bacterial microbiota and vector competence analyses. One week-old Ae. aegypti females reared either in their breeding site water (field) or in dechlorinated tap water supplemented with rabbit food (laboratory) were blood fed either in presence or absence of Amoxicillin/ Clavulanic Acid combination (Amox/Clav). Midguts were dissected at 7 and 21 days post-exposure (dpe) before metagenomics analysis. In addition, females were infected with DENV-1 with or without the presence of the antibiotic Amox/Clav. Digestive tracts were dissected at 48 h, 7 and 21 dpe for metagenomics analysis. Individual mosquito bodies, heads and saliva were also collected at 7, 14 and 21 dpe to respectively estimate infection rate, dissemination rate, transmission rate and transmission efficiencies.

Figure 2

Impact of Amox/Clav ingestion during blood meal on Ae. aegypti bacterial microbiota. Bacterial microbiota was determined on females reared in their breeding site water (field condition) or in dechlorinated tap water supplemented with rabbit food (laboratory condition) either in presence (B + ATB) or in absence (B−ATB) of the antibiotic in the blood meal. Genera abundance (A), alpha diversity (Richness (B), Shannon (C), and Simpson (D) indices, and beta diversity (E) were estimated at 7 and 21 days after the blood meal. The number of amplicon simple variants (ASVs) is indicated above each barplot.

Figure 3

Impact of Amox/Clav ingestion during the infected blood meal on Ae. aegypti bacterial microbiota. The bacterial microbiota was determined for females reared in dechlorinated tap water supplemented with rabbit food (laboratory condition), either in the presence (D + ATB) or absence (D−ATB) of the antibiotic during the infection blood meal containing DENV. Genera abundance (A), alpha diversity (B) and beta diversity (C) were recorded at 48 h, 7 and 21 days after the blood meal. The number of single amplicon variants (ASVs) is shown above each barplot.

Figure 4

Impact of simultaneous ingestion of DENV-1 and Amox/Clavon Ae. aegypti vector competence at 7, 14 and 21 days after exposure. Dengue virus infection rate (A), dissemination rate (C), transmission rate (F), transmission efficiency (G) and DENV-1 viral loads (E). Comparison between real-time RT-PCR and viral titration estimations for infection (B), dissemination (D) in presence (D + ATB) or absence (D−ATB) of the Amox/Clav in the infectious blood meal. Infection was estimated from mosquito midguts, dissemination from heads and transmission from saliva. Error bars indicate 95% confidence intervals for each condition. Significant differences are indicated by asterisks (**P < 0.01).