Search

ABSTRACT Mosquitoes are important vectors for many arboviruses. It is becoming increasingly clear that various symbiotic microorganisms (including bacteria and insect-specific viruses; ISVs) in mosquitoes have the potential to modulate the ability of mosquitoes to transmit arboviruses. In this study, we compared the bacteriome and virome (both eukaryotic viruses and bacteriophages) of female adult Aedes aegypti and Culex quinquefasciatus mosquitoes fed with sucrose/water, blood, or blood spiked with Zika virus (ZIKV) or West Nile virus (WNV), respectively. Furthermore, we investigated associations between the microbiota and vector competence. We show that the influence of arboviruses on the mosquito microbiome—and vice versa—is distinct for each combination of arbovirus/mosquito species. The presence of ZIKV resulted in a temporarily increased Aedes ISV diversity. However, this effect was distinct for different ISVs: some ISVs decreased following the blood meal (Aedes aegypti totivirus), whereas other ISVs increased only when the blood contained ZIKV (Guadeloupe mosquito virus). Also, the diversity of the Aedes bacteriome depended on the diet and the presence of ZIKV, with a lower diversity observed for mosquitoes receiving blood without ZIKV. In Cx. quinquefasciatus, some ISVs increased in WNV-infected mosquitoes (Guadeloupe Culex tymo-like virus). Particularly, the presence of Wenzhou sobemo-like virus 3 (WSLV3) was associated with the absence of infectious WNV in mosquito heads, suggesting that WSLV3 might affect vector competence for WNV. Distinct profiles of bacteriophages were identified in Culex mosquitoes depending on diet, despite the lack of clear changes in the bacteriome. Overall, our data demonstrate a complex three-way interaction among arboviruses, resident microbiota, and the host, which is distinct for different arbovirus–mosquito combinations. A better understanding of these interactions may lead to the identification of microbiota able to suppress the ability of arbovirus transmission to humans, and hence improved arbovirus control measures. IMPORTANCE In this study, we first utilized the single mosquito microbiome analysis, demonstrating a complex three-way interaction among arboviruses, resident microbiota, and the host, which is distinct for different arbovirus–mosquito combinations. Some of the previously described “core virus” increased in the mosquitos receiving viral blood meal, like Guadeloupe mosquito virus and Guadeloupe Culex tymo-like virus, suggesting their potential roles in ZIKV and WNV infection. Notably, Wenzhou sobemo-like virus 3 was associated with the absence of infectious WNV in heads of Culex mosquitoes, which might affect vector competence for WNV. A better understanding of these interactions will lead to the identification of microbiota able to suppress the ability of arbovirus transmission to humans, and hence improved arbovirus control measures.

ABSTRACT Disturbances in the primary colonization of the infant gut can result in lifelong consequences and have been associated with a range of host conditions. Although early-life factors have been shown to affect infant gut microbiota development, our current understanding of human gut colonization in early life remains limited. To gain more insights into the unique dynamics of this rapidly evolving ecosystem, we investigated the microbiota over the first year of life in eight densely sampled infants (n = 303 total samples). To evaluate the gut microbiota maturation transition toward an adult configuration, we compared the microbiome composition of the infants to that of the Flemish Gut Flora Project (FGFP) population (n = 1,106). We observed the infant gut microbiota to mature through three distinct, conserved stages of ecosystem development. Across these successional gut microbiota maturation stages, the genus predominance was observed to shift from Escherichia over Bifidobacterium to Bacteroides. Both disease and antibiotic treatment were observed to be associated occasionally with gut microbiota maturation stage regression, a transient setback in microbiota maturation dynamics. Although the studied microbiota trajectories evolved to more adult-like constellations, microbiome community typing against the background of the FGFP cohort clustered all infant samples within the (in adults) potentially dysbiotic Bacteroides 2 (Bact2) enterotype. We confirmed the similarities between infant gut microbial colonization and adult dysbiosis. Profound knowledge about the primary gut colonization process in infants might provide crucial insights into how the secondary colonization of a dysbiotic adult gut can be redirected. IMPORTANCE After birth, microbial colonization of the infant intestinal tract is important for health later in life. However, this initial process is highly dynamic and influenced by many factors. Studying this process in detail requires a dense longitudinal sampling effort. In the current study, the bacterial microbiota of >300 stool samples was analyzed from 8 healthy infants, suggesting that the infant gut microbial population matures along a path involving distinct microbial constellations and that the timing of these transitions is infant specific and can temporarily retrace upon external events. We also showed that the infant microbial populations show similarities to suboptimal bacterial populations in the guts of adults. These insights are crucial for a better understanding of the dynamics and characteristics of a “healthy gut microbial population” in both infants and adults and might allow the identification of intervention targets in cases of microbial disturbances or disease.

ABSTRACT Disturbances in the primary colonization of the infant gut can result in lifelong consequences and have been associated with a range of host conditions. Although early-life factors have been shown to affect infant gut microbiota development, our current understanding of human gut colonization in early life remains limited. To gain more insights into the unique dynamics of this rapidly evolving ecosystem, we investigated the microbiota over the first year of life in eight densely sampled infants (n = 303 total samples). To evaluate the gut microbiota maturation transition toward an adult configuration, we compared the microbiome composition of the infants to that of the Flemish Gut Flora Project (FGFP) population (n = 1,106). We observed the infant gut microbiota to mature through three distinct, conserved stages of ecosystem development. Across these successional gut microbiota maturation stages, the genus predominance was observed to shift from Escherichia over Bifidobacterium to Bacteroides. Both disease and antibiotic treatment were observed to be associated occasionally with gut microbiota maturation stage regression, a transient setback in microbiota maturation dynamics. Although the studied microbiota trajectories evolved to more adult-like constellations, microbiome community typing against the background of the FGFP cohort clustered all infant samples within the (in adults) potentially dysbiotic Bacteroides 2 (Bact2) enterotype. We confirmed the similarities between infant gut microbial colonization and adult dysbiosis. Profound knowledge about the primary gut colonization process in infants might provide crucial insights into how the secondary colonization of a dysbiotic adult gut can be redirected. IMPORTANCE After birth, microbial colonization of the infant intestinal tract is important for health later in life. However, this initial process is highly dynamic and influenced by many factors. Studying this process in detail requires a dense longitudinal sampling effort. In the current study, the bacterial microbiota of >300 stool samples was analyzed from 8 healthy infants, suggesting that the infant gut microbial population matures along a path involving distinct microbial constellations and that the timing of these transitions is infant specific and can temporarily retrace upon external events. We also showed that the infant microbial populations show similarities to suboptimal bacterial populations in the guts of adults. These insights are crucial for a better understanding of the dynamics and characteristics of a “healthy gut microbial population” in both infants and adults and might allow the identification of intervention targets in cases of microbial disturbances or disease.