Aphids are widespread agricultural pests that are capable of disseminating plant viral diseases; however, despite coming into frequent contact with epiphytic bacteria, aphids are considered to have no role in bacterial transmission. Here, we demonstrate the ability of pea aphids to vector the phytopathogen Pseudomonas syringae pv. syringae B728a (PsyB728a). While feeding on plants colonized by epiphytic bacteria, aphids acquire the bacteria, which colonize the digestive tract, multiply, and are excreted in the aphid honeydew, resulting in inoculation of the phyllosphere with up to 10 7 phytopathogenic bacteria per cm 2 . Within days of ingesting bacteria, aphids succumb to bacterial sepsis, indicating that aphids serve as an alternative, nonplant host for PsyB728a. The related strain Pseudomonas syringae pv. tomato DC3000 is >1,000-fold less virulent than PsyB728a in the pea aphid, suggesting that PsyB728a possesses strain-specific pathogenicity factors that allow it to exploit aphids as hosts. To identify these factors, we performed a mutagenesis screen and recovered PsyB728a mutants that were hypovirulent, including one defective in a gene required for flagellum formation and motility. These interactions illustrate that aphids can also vector bacterial pathogens and that even seemingly host-restricted pathogens can have alternative host specificities and lifestyles.Aphids are prolific insect pests that impact numerous agricultural crop plants (8). Although direct parasitization of their hosts can reduce plant biomass, crop quality, and crop yield, aphids are of particular importance for their role in the dissemination of plant disease (24, 30). Phytopathogenic viruses can be acquired by aphids as they probe infected plant hosts with their stylet (29,30), with the subsequent movement of infected aphids to healthy plants contributing significantly to the dissemination of plant disease (29). Surprisingly, however, aphids are considered strictly vectors of phytopathogenic viruses, despite their frequent physical contact with a variety of bacterial epiphytes (10).Upon landing on a potential host, the aphid begins to explore the plant, probing the plant tissues with its stylet and puncturing through the epidermal layers to locate and access the phloem sieve tube elements to feed (3,18,24). As it traverses the plant surface, the aphid continually evaluates the suitability of the host, with some aphid species sampling plant fluids with droplets of saliva that are expelled and reingested (3). This saliva can contact the plant surface where many bacterial epiphytes reside, such as the ubiquitous phytopathogens Pantoea agglomerans and Pseudomonas syringae (4,5,10,21,22,32).The pea aphid, Acyrthosiphon pisum, feeds on a variety of agriculturally relevant crop plants in the Fabaceae, including soybean (Glycine max), fava/broad bean (Vicia faba), pea (Pisum sativum), and snap bean (Phaseolus vulgaris) (15,28,(34)(35)(36), and has been shown to vector bean yellow mosaic virus between these hosts (15,(34)(35)(36). Several of ...

This cohort study uses data clustering methods and clinical stakeholder assessment to identify clinical profiles in a population of medically complex patients.

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Background: Adverse social conditions are a key contributor to health disparities. Improved understanding of how social risk factors interact with each other and with neighborhood characteristics may inform efforts to reduce health disparities.Data: A questionnaire of 29,281 patients was collected through the enrollment of Medicaid beneficiaries in a large Northern California integrated health care delivery system between May 2016 and February 2020.Exposures: Living in the least resourced quartile of neighborhoods as measured by a census-tract level Neighborhood Deprivation Index score.Main Outcomes: Five self-reported social risk factors: financial need, food insecurity, housing barriers, transportation barriers, and functional limitations.Results: Nearly half (42.0%) of patients reported at least 1 social risk factor; 22.4% reported 2 or more. Mean correlation coefficient between social risk factors was ρ = 0.30. Multivariable logistic models controlling for age, race/ethnicity, sex, count of chronic conditions, and insurance source estimated that living in the least resourced neighborhoods was associated with greater odds of food insecurity (adjusted odds ratio = 1.07, 95% confidence interval: 1.00-1.13) and transportation barriers (adjusted odds ratio = 1.20, 95% confidence interval: 1.11-1.30), but not financial stress, housing barriers, or functional limitations.Conclusions and Relevance: We found that among 5 commonly associated social risk factors, Medicaid patients in a large Northern California health system typically reported only a single factor and that these factors did not correlate strongly with each other. We found only modestly greater social risk reported by patients in the least resourced neighborhoods. These results suggest that individuallevel interventions should be targeted to specific needs whereas community-level interventions may be similarly important across diverse neighborhoods.