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IntroductionThe exposome concept provides a framework to better incorporate the environment into the study of health and disease and has been defined by academics to encompass all lifetime exposures including toxicants, diet, and lifestyle choices. However, initial applications of the exposome concept have been less apt at measuring social determinants of health, focusing primarily on conventional environmental exposures and lifestyle choices that do not reflect the complex lived experience of many communities. To bring community voice into the exposome concept, the HERCULES Exposome Research Center and its Stakeholder Advisory Board co-developed the Exposome Roadshow. We present and discuss the resulting community-exposome definition to inform and improve exposome research.Materials and MethodsFour communities from distinct areas across metro-Atlanta participated in separate 2-day Exposome Roadshow workshops with concept mapping. Aligned with a popular education approach in which community knowledge is used to work collectively for change, concept mapping provided a systematic method to collect and visualize community members' knowledge and create a shared understanding to take action. Community members brainstormed, sorted, and rated their responses to the prompt: “What in your environment is affecting your and your community's health?” Responses were analyzed and visually depicted by concept maps consisting of separate but interrelated clusters of ideas. Community members discussed and validated the maps, selecting a final map illustrating their community's exposome.ResultsA total of 118 community members completed concept mapping. On average communities identified 7 clusters to define their exposome. The resulting concept maps offer a community definition of the exposome. Five major themes arose across all four communities: conventional environmental concerns, built environment, social relationships, crime and safety, and individual health and behaviors.DiscussionThe resulting community-exposome definition demonstrates the importance of expanding the scope of exposures beyond traditional environmental influences to include the lived experience of individuals and communities. While newer exposome definitions align more closely with this community definition, traditional exposome methods do not routinely include these factors. To truly capture the totality of lifetime exposures and improve human health, researchers should incorporate community perspectives into exposome research.

ABSTRACT Ordered transposon libraries are a valuable resource for many bacterial species, especially those with difficult methods for generating targeted genetic mutations. Here, we present the construction of an ordered transposon library for the bacterial urinary tract pathogen Proteus mirabilis strain HI4320. This library will facilitate future studies into P. mirabilis biology. For large experimental screens, it may be used to overcome bottleneck constraints and avoid biased outcomes resulting from gene length. For smaller studies, the library allows sidestepping the laborious construction of single targeted mutants. This library, containing 18,432 wells, was condensed into a smaller library containing 1,728 mutants. Each selected mutant had a single transposon insertion in an open reading frame, covering 45% of predicted genes encoded by P. mirabilis HI4320. This coverage was lower than expected and was due both to library wells with no mapped insertions and a surprisingly high proportion of mixed clones and multiple transposon insertion events. We offer recommendations for improving future library construction and suggestions for how to use this P. mirabilis library resource. IMPORTANCE Ordered libraries facilitate large genetic screens by guaranteeing high genomic coverage with a minimal number of mutants, and they can save time and effort by reducing the need to construct targeted mutations. This resource is now available for P. mirabilis, a common and complicating agent of catheter-associated urinary tract infection. We also present obstacles encountered during library construction with the goal to aid others who would like to construct ordered transposon libraries in other species.

Proteus mirabilis, a Gram-negative uropathogen, is a major causative agent in catheter-associated urinary tract infections (CAUTI). Mannose-resistant Proteus-like fimbriae (MR/P) are crucially important for P. mirabilis infectivity and are required for biofilm formation and auto-aggregation, as well as for bladder and kidney colonization. Here, the X-ray crystal structure of the MR/P tip adhesin, MrpH, is reported. The structure has a fold not previously described and contains a transition metal center with Zn2+ coordinated by three conserved histidine residues and a ligand. Using biofilm assays, chelation, metal complementation, and site-directed mutagenesis of the three histidines, we show that an intact metal binding site occupied by zinc is essential for MR/P fimbria-mediated biofilm formation, and furthermore, that P. mirabilis biofilm formation is reversible in a zinc-dependent manner. Zinc is also required for MR/P-dependent agglutination of erythrocytes, and mutation of the metal binding site renders P. mirabilis unfit in a mouse model of UTI. The studies presented here provide important clues as to the mechanism of MR/P-mediated biofilm formation and serve as a starting point for identifying the physiological MR/P fimbrial receptor.