Biology subjects

Coon, K. L.

Publications and source records attributed to Coon, K. L..

10 recordsLinked to original sources

bioRxiv2025

Vertical transmission of mosquito microbiota and its effects on offspring development

BackgroundThe mosquitos gut microbiota plays a crucial role in determining its capacity to transmit harmful viruses and parasites. Accordingly, manipulating mosquito gut microbiota is a promising avenue towards reducing mosquito-borne human pathogen transmission. A successful microbial control campaign will require a thorough understanding of how bacteria are transmitted through mosquito populations. Through two parallel but complementary studies using the yellow fever mosquito Aedes aegypti as a focal host species, we surveyed vertical transmission of bacteria from individual mothers to cohorts of offspring maintained in a closed system. ResultsLaboratory- and field-derived mothers deposited bacteria that support offspring development, and the relative abundance of commonly transmitted taxa correlated with offspring fitness. Maternally transmitted bacteria were detected in both larval and adult offspring, and the relative abundances of specific taxa differed between life stages. Microbiota composition in adult offspring closely resembled microbiota composition in mothers, despite dramatic shifts in the relative abundance of specific microbial community members during the larval stage. Variability in microbiota composition in offspring was also greater than variability across the population of egg-laying mothers. Eggs that underwent a period of desiccation before hatching produced larval communities dominated by endospore-forming bacteria that were rare in maternal samples. ConclusionsOverall, our results demonstrate the vertical transmission of mosquito-associated microbiota across generations, including bacterial taxa that could potentially be leveraged for mosquito and mosquito-borne disease control.

microbiology↗

bioRxiv2025

Comparative genomics reveals phylogenetic intermixing of Stomoxys fly, manure, and bovine mastitis-associated bacteria in dairy settings

Stomoxys flies are highly ubiquitous blood-feeding pests on dairy farms and are suspected carriers of pathogenic bacteria due to their close association with both manure reservoirs and cattle hosts. While prior studies using amplicon sequencing and culture dependent methodologies have been used to characterize the composition of the Stomoxys microbiota, little is known about strain level genomic and functional diversity of Stomoxys-associated bacteria. In this study, we address this key gap in knowledge by using whole genome sequencing to provide the first comparative genomic analysis of Stomoxys-derived Escherichia coli, Klebsiella pneumoniae, and Staphylococcaceae isolates. Our results show that fly and manure isolates collected from the same farm system are phylogenetically interspersed, with subsequent pairwise genome alignments revealing near identical strains and plasmids shared between the two sources. We further identified a phylogenetic clade of Mammaliicoccus sciuri, which contains known mastitis agents that were associated with both flies and manure. Functional analysis revealed that this clade was highly enriched in xylose metabolism genes that were rare across other M. sciuri lineages, suggesting potential niche differentiation within the genus. Collectively, our results provide strong evidence for the acquisition of fecal-associated bacterial isolates by adult Stomoxys flies, confirming the link between biting muscid flies and manure habitats. The intermixing of fly and manure isolates in clinically relevant taxonomic groups strongly suggests that flies serve as carriers of opportunistic mastitis-causing or other fecal-borne pathogens, and that flies may serve as important vehicles of pathogen dissemination across the dairy farm environment. Author summaryBlood-feeding Stomoxys flies are a major pest species in dairy operations and have been implicated as carriers of fecal-borne pathogens responsible for bovine mastitis and other important cattle diseases. In a previous study, we generated a large collection of bacterial isolates from manure and Stomoxys flies collected from dairy barns. Most bacterial isolates derived from flies were identified as taxa associated with bovine mastitis, including Escherichia coli, Klebsiella pneumoniae, and non-aureus Staphylococcus; however, it is unknown if these represent bacterial strains acquired by flies from manure. Here, we examined this possibility directly by performing whole genome sequencing of a subset of potential mastitis pathogens derived primarily from flies and manure and supplemented this analysis with publicly available genomes on NCBI (including mastitis and additional fly and manure strains). Our results reveal significant interrelations between fly, manure, and clinically derived mastitis strains, suggesting that Stomoxys flies participate in the carriage and dissemination of bovine mastitis pathogens acquired from manure. Additionally, this work highlights the functional diversity of bacterial pathogens within the barn environment and greatly expands the available genomic data for understudied mastitis pathogens such as Mammaliicoccus sciuri.

microbiology↗

bioRxiv2024

Prevalence of antimicrobial resistance phenotypes and genes in stable fly- and manure-derived bacterial isolates from clinically relevant taxa in dairy settings

AimsThis study aimed to characterize and compare the antimicrobial resistance (AMR) profiles of clinically relevant bacterial taxa isolated from biting stable flies (Stomoxys spp.) and bovine manure samples collected at a dairy research facility over the course of an entire fly breeding season. The presence of extended-spectrum beta-lactamase (ESBL) and other antimicrobial resistance genes (ARGs) was also examined. Methods and resultsA total of 606 fly- and 180 manure-derived strains were tested via disk diffusion for susceptibility to commonly administered antibiotics used in veterinary and human medicine. A small percentage of Enterobacterales exhibited resistance to the tested antimicrobials, including ceftiofur and other beta-lactam antibiotics. Extended spectrum beta-lactamase genes (TEM, CTX, OXA, CMY) were detected by PCR amplification in ceftiofur-resistant Escherichia coli, Klebsiella and Enterobacter spp. isolates. We additionally identified pirlimycin-resistant Staphylococcus and Mammaliicoccus spp. isolates encoding lnuA, a lincosamide resistance gene found primarily on small mobilizable plasmids. ConclusionsThese findings highlight the significance of stable flies in the carriage of antimicrobial-resistant bacterial strains and plasmid-associated ARGs on dairy farms.

microbiology↗

bioRxiv2024

Opportunistic pathogens are prevalent across the culturable exogenous and endogenous microbiota of stable flies captured at a dairy facility

Stable flies in the genus Stomoxys are highly abundant, blood-feeding pests on dairy farms; however, their role in the carriage and potential transmission of pathogens is largely understudied. Here, we report on the frequency and distribution of culturable bacteria collected from Stomoxys flies captured in free stall barns and nearby calf hutches over a three-month period on a focal research farm in Wisconsin, USA. Mastitis-associated bacterial taxa, including Staphylococcus, Escherichia, Enterobacter, and Klebsiella spp., were frequently isolated from pooled samples of the internal or external portions of the flies. Conversely, selective enrichment protocols from these samples yielded only a single isolate of Salmonella and no enterohemorrhagic Escherichia coli O157. Neither trap location nor time of capture had a significant impact on the observed frequency of most bacterial genera isolated from the flies. Our results confirm that Stomoxys flies harbor both mastitis-associated bacterial taxa and bacterial taxa associated with opportunistic infections in humans. Further research into the transmission of fly-associated microbes could be important in the control of mastitis or other bacterial diseases on dairy farms.

microbiology↗

bioRxiv2024

Stable flies harbor a low complexity microbiota dominated by mastitis-associated bacteria

Hematophagous Stomoxys (stable) fly populations in dairy barns are sustained by a constant availability of cattle hosts and manure, which serve as major reservoirs of both zoonotic and opportunistic bacterial pathogens. However, the overall composition and diversity of bacterial communities associated with Stomoxys flies and the ability of biting flies to acquire and transmit potentially pathogenic bacteria present in their surrounding environment remain to be investigated. Here, we present the first culture-independent examination of Stomoxys-associated bacterial communities through longitudinal sampling of fly and manure samples collected from two connected dairy facilities in South Central Wisconsin. High throughput 16S rRNA gene amplicon sequencing was used to characterize and compare bacterial communities present on or within flies and in manure collected from the same facility. Bacterial alpha diversity was overall higher in manure samples as compared to fly samples, with manure-associated bacterial communities being dominated by members of the Bacteroidales, Eubacteriales, and Oscillospirales. In contrast, flies harbored relatively low-complexity communities dominated by members of the Enterobacterales, Staphylococcales, and Lactobacillales. Clinically relevant bacterial strains, including Escherichia spp. and other taxa associated with mastitic cows housed in the same facilities, were detected in paired fly and manure samples but exhibited dramatically elevated abundances in fly samples as compared to manure samples. Viable colonies of Escherichia, Klebsiella, and Staphylococcus spp. were also readily isolated from fly samples, confirming that flies harbor culturable mastitis associated bacteria. This study provides definitive support for a potential role for biting flies in mediating bacterial pathogen transmission in dairy barns and other agricultural settings. IMPORTANCEDisease prevention on dairy farms has significant implications for cattle health, food security, and zoonosis. Of particular importance is the control of bovine mastitis, which can be caused by a diverse array of environmental bacterial pathogens, including Klebsiella, E. coli, Streptococcus, and Staphylococcus spp. Despite being one of the most significant and costly cattle diseases worldwide, the epidemiology of bovine mastitis is not well understood. This study provides the first culture-dependent and culture-independent evidence to support the potential for biting flies to transmit opportunistic bovine and human pathogens in agricultural settings. It also links carriage of specific bacterial taxa in flies to clinical mastitis cases in cows housed in the same facility at the time of sampling. Altogether, these results indicate that biting flies represent an important, yet understudied biosecurity threat to animal husbandry facilities.

microbiology↗

bioRxiv2023

Establishment and comparative genomics of a high-quality collection of mosquito-associated bacterial isolates -- MosAIC (Mosquito-Associated Isolate Collection)

Mosquitoes transmit medically important human pathogens, including viruses like dengue virus and parasites such as Plasmodium spp., the causative agent of malaria. Mosquito microbiomes are critically important for the ability of mosquitoes to transmit disease-causing agents. However, while large collections of bacterial isolates and genomic data exist for vertebrate microbiomes, the vast majority of work in mosquitoes to date is based on 16S rRNA gene amplicon data that provides limited taxonomic resolution and no functional information. To address this gap and facilitate future studies using experimental microbiome manipulations, we generated a bacterial Mosquito-Associated Isolate Collection (MosAIC) consisting of 392 bacterial isolates with extensive metadata and high-quality draft genome assemblies that are publicly available for use by the scientific community. MosAIC encompasses 142 species spanning 29 bacterial families, with members of the Enterobacteriaceae comprising 40% of the collection. Phylogenomic analysis of three genera, Enterobacter, Serratia, and Elizabethkingia, reveal lineages of mosquito-associated bacteria isolated from different mosquito species in multiple laboratories. Investigation into species pangenomes further reveals clusters of genes specific to these lineages, which are of interest for future work to identify functions underlying mosquito host association. Altogether, we describe the generation of a physical collection of mosquito-associated bacterial isolates, their genomic data, and analyses of selected groups in context of genome data from closely related isolates, providing a unique, highly valuable resource to investigate factors for bacterial colonisation and adaptation within mosquito hosts. Future efforts will expand the collection to include broader geographic and host species representation, especially from individuals collected from field populations, as well as other mosquito-associated microbes, including fungi, archaea, and protozoa.

microbiology↗

bioRxiv2023

Aedes aegypti gut transcriptomes respond differently to microbiome transplants from field-caught or laboratory-reared mosquitoes.

The mosquito microbiome is critical for host development and plays a major role in many aspects of mosquito biology. While the microbiome is commonly dominated by a small number of genera, there is considerable variation in composition among mosquito species, life stages, and geography. How the host controls and is affected by this variation is unclear. Using microbiome transplant experiments, we asked whether there were differences in transcriptional responses when mosquitoes of different species were used as microbiome donors. We used microbiomes from four different donor species spanning the phylogenetic breadth of the Culicidae, collected either from the laboratory or field. We found that when recipients received a microbiome from a donor reared in the laboratory, the response was remarkably similar regardless of donor species. However, when the donor had been collected from the field, far more genes were differentially expressed. We also found that while the transplant procedure did have some effect on the host transcriptome, this is likely to have had a limited effect on mosquito fitness. Overall, our results highlight the possibility that variation in mosquito microbiome communities are associated with variability in host-microbiome interactions and further demonstrate the utility of the microbiome transplantation technique.

microbiology↗

bioRxiv2022

Cryopreservation of mosquito microbiota for use in microcosm experiments

Mosquitoes develop in a wide range of aquatic habitats containing highly diverse and variable bacterial communities that shape both larval and adult traits, including the capacity of adult females of some mosquito species to vector disease-causing organisms to humans. However, while most mosquito studies control for host genotype and environmental conditions, the impact of microbiota variation on phenotypic outcomes of mosquitoes is often unaccounted for. The inability to conduct reproducible intra- and inter-laboratory studies of mosquito-microbiota interactions has also greatly limited our ability to identify microbial targets for mosquito-borne disease control. Here, we developed an approach to isolate and cryopreserve microbial communities derived from mosquito larval rearing environments in the lab and field. We then validated the use of our approach to generate experimental microcosms colonized by standardized lab- and field-derived microbial communities. Our results overall reveal minimal effects of cryopreservation on the recovery of bacteria when directly compared with isolation from non-cryopreserved fresh material. Our results also reveal improved reproducibility of microbial communities in replicate microcosms generated using cryopreserved stocks over fresh material. Altogether, these results provide a critical next step toward the standardization of mosquito studies to include larval rearing environments colonized by defined microbial communities. They also lay the foundation for long-term studies of mosquito-microbe interactions and the identification and manipulation of taxa with potential to reduce mosquito vectorial capacity.

microbiology↗

bioRxiv2021

Inter-species microbiota transplantation recapitulates microbial acquisition and persistence in mosquitoes

BackgroundMosquitoes harbor microbial communities that play important roles in their growth, survival, reproduction, and ability to transmit human pathogens. Microbiome transplantation approaches are often used to study host-microbe interactions and identify microbial taxa and assemblages associated with health or disease. However, no such approaches have been developed to manipulate the microbiota of mosquitoes. ResultsHere, we developed an approach to transfer entire microbial communities between mosquito cohorts. We undertook transfers between (Culex quinquefasciatus to Aedes aegypti) and within (Ae. aegypti to Ae. aegypti) species to validate the approach and determine the number of mosquitoes required to prepare donor microbiota. After the transfer, we monitored mosquito development and microbiota dynamics throughout the life cycle. Typical holometabolous lifestyle-related microbiota structures were observed, with higher dynamics of microbial structures in larval stages, including the larval water, and less diversity in adults. Microbiota diversity in recipient adults was also more similar to the microbiota diversity in donor adults. ConclusionsThis study provides the first evidence for successful microbiome transplantation in mosquitoes. Our results highlight the value of such methods for studying mosquito-microbe interactions and lay the foundation for future studies to elucidate the factors underlying microbiota acquisition, assembly, and function in mosquitoes under controlled conditions.

microbiology↗

bioRxiv2020

Host-environment interplay shapes fungal diversity in mosquitoes

Mosquito larvae encounter diverse assemblages of bacteria (i.e. microbiota) and fungi (i.e. mycobiota) in the aquatic environments they develop in. However, while a number of studies have addressed the diversity and function of microbiota in mosquito life history, relatively little is known about mosquito-mycobiota interactions outside of several key fungal entomopathogens. In this study, we used high-throughput sequencing of ITS2 gene amplicons to provide the first simultaneous characterization of the mycobiota in field-collected Aedes albopictus larvae and their associated aquatic environments. Our results reveal unprecedented variation in mycobiota among adjacent but discrete larval breeding habitats. Our results also reveal distinct mycobiota assembly in the mosquito gut versus other tissues, with gut-associated fungal communities being most similar to those present in the environment where larvae feed. Altogether, our results identify the environment as the dominant factor shaping mosquito mycobiota with no evidence of environmental filtering of the gut mycobiota. These results also identify mosquito feeding behavior and fungal mode of nutrition as potential drivers of tissue-specific mycobiota assembly after environmental acquisition. IMPORTANCEThe Asian tiger mosquito, Aedes albopictus, is the dominant mosquito species in the USA and an important vector of arboviruses of major public health concern. One aspect of mosquito control to curb mosquito-borne diseases has been the use of biological control agents such as fungal entomopathogens. Recent studies also demonstrate the impact of mosquito-associated microbial communities on various mosquito traits, including vector competence. However, while much research attention has been dedicated to understanding the diversity and function of mosquito-associated bacterial communities, relatively little is known about mosquito-associated fungal communities. A better understanding of the factors that drive mycobiota diversity and assembly in mosquitoes will be essential for future efforts to target mosquito micro- and mycobiomes for mosquito and mosquito-borne disease control.

microbiology↗