Methicillin resistant Staphylococcus aureus (MRSA) is an antibiotic resistant pathogen that causes severe illness and thousands of deaths each year in the US. It spreads within the community through improper hand hygiene and is often found in hospitals and on public transport surfaces. This poses a danger to the public, specifically to vulnerable populations such as the elderly and immunocompromised. This study in Seattle, Washington compares the prevalence of the antibiotic-resistant MRSA bacterium on public transport surfaces both proximate and distant to Harborview Hospital. Swabs from bus stops and pedestrian call buttons were collected outside of Harborview Hospital and urban areas of Capitol Hill, a Seattle neighborhood approximately one mile away from any major hospitals. The swabs were streaked onto Tryptic Soy Agar plates, gram stained, and streaked on Mannitol Salt agar plates;catalase and coagulase tests were run to help further confirm the presence of Staphylococcus aureus. The resulting colonies were then screened for antibiotic resistance using the Kirby Bauer Disk Diffusion method. One instance of potential MRSA was isolated from a crosswalk button in Capitol Hill. A higher MRSA prevalence on surfaces close to hospitals could establish a link between the spread of pathogenic bacteria from hospitals to Seattle's city surfaces but was not found in this study. These results suggest that the spread of MRSA in Seattle may have more to do with foot traffic and public transportation usage. However, the presence of MRSA on urban surfaces puts sensitive populations at risk regardless of its source. Practicing good hand hygiene can help curb the spread of MRSA in the community.

Snow is an essential resource, especially in the Pacific Northwest, where it provides clean drinking water, irrigation water, and helps prevent wildfires. Despite the importance of the snowpacks in the Pacific Northwest, the composition of snow is not well documented. The ion concentrations in snow can indicate where the snow came from. I have created a dataset of the concentrations of anions found in snow throughout Washington State. Snow samples were collected primarily throughout the Cascade Mountain Range by volunteers using sterilized plastic containers. Samples were melted and then analyzed using ion chromatography to quantify the anions in each sample. Samples were found to contain concentrations of fluoride, chloride, nitrate, bromide, phosphate, nitrite, and sulfate. These anions have previously been found to be present in glaciers, clouds, and freshly fallen snow. Cataloging these anions provides an important baseline from which to observe how human and natural impacts, including climate change, are affecting the snow in the Pacific Northwest.

Many transgender and gender diverse (TGD) people desire gender-affirming hormone treatment (GAHT) to alleviate discomfort due to the misalignment of one’s gender identity with their secondary sex characteristics, though little is known about its effects on the body. One area of interest that may be affected by GAHT is the gut microbiota (GM). GM and the sex hormones (estrogen, testosterone, and progesterone) have been shown to interact bidirectionally, referred to as the “gut microsexome.” At puberty, the commensal microbiota of males and females diverge due to circulating sex hormones. This difference is hypothesized to contribute to sexual dimorphism of disease prevalence between cisgender males and females, although little research on the effect of GAHT in the TGD population exists. Alteration of the gut microbiota, or dysbiosis, also has many adverse effects that overlap those of testosterone GAHT (THT) such as acne, weight gain, and hypercholesterolemia. Dysbiosis has also been shown to lead to intestinal and systemic inflammation by disrupting immune function. More information on the effects of THT on the gut microbiota is necessary to counsel transmasculine clients effectively. In this study, we injected mice born of the female sex biweekly with testosterone enanthate dissolved in sesame oil versus sesame oil alone. We profiled GM of mice throughout treatment using 16S rRNA sequencing and measured markers of inflammation in serum to assess the effect of THT on both the population of GM and intestinal and systemic inflammation. We expect that the mice receiving THT will have differentially abundant gut microbiota and increased concentration of inflammatory markers compared to controls. The findings of this study will serve as a basis for further studies exploring additional analysis of the gut microbiota and inflammation in both transmasculine and transfeminine people receiving GAHT.

Atherosclerosis is characterized by the accumulation of lipids, inflammatory cells, and fibrous tissue in arterial walls, forming plaques. Plaque accumulation can lead to stenosis and potentially severe outcomes such as myocardial infarction or stroke. The gut microbiome, including Collinsella aerofaciens, is believed to play a role in the prevention or development of atherosclerosis. Gut bacteria can directly influence systemic inflammation, a factor correlated with the pathogenesis of atherosclerosis, and produce metabolites that alter the disease course. This study explores the potential link between C. aerofaciens and atherosclerosis by investigating the abundance of C. aerofaciens in the gut microbiome of individuals with and without atherosclerosis. We collected 179 stool samples from participants at the Kisumu District Hospital HIV Clinic in Kenya and conducted a comprehensive analysis of their gut microbiomes. 100 participants had carotid ultrasonography, categorized as showing atherosclerosis with visible plaque or intima medial thickness ≥ 0.7 mm. We employed bacterial 16S ribosomal RNA gene sequencing to characterize the stool microbial composition and noted that the relative abundance of C. aerofaciens was 2.6-fold less in participants with atherosclerosis (p=0.006). To validate these findings, I employed a Quantitative Polymerase Chain Reaction with a cloned plasmid control for targeted quantification of C. aerofaciens. We found 6.9-fold more C. aerofaciens copies per total 16S in Kenyan adults without atherosclerosis versus with (p=0.020). This suggests a potential protective or mitigating role for this bacterium in cardiovascular health. Future work could include assessing changes in C. aerofaciens abundance over time and its association with cardiovascular disease progression. Additionally, in vitro or preclinical studies could reveal the specific mechanisms by which C. aerofaciens influences atherosclerosis development and progression. This research contributes to our understanding of the intricate interplay between the gut microbiome and atherosclerosis, offering insights that may inform future therapeutic strategies and personalized interventions for cardiovascular diseases.

Exclusionary zoning laws — which limit population densities and land uses in specific neighborhoods — are a typical feature of American municipal land use regulation. An extensive body of evidence links traffic-related air pollutant (TRAP) exposure to adverse health effects. Using zoning data and a model of TRAP levels in cities across the Seattle metropolitan area, I hypothesize that TRAP exposure will be greater on average in zones where higher-density housing is an allowed use, and lower on average in zones reserved for lower-density housing. I used the software package QGIS to spatially join zoning and air pollution data and used the software package R to perform correlation analyses between zone types (classified by maximum population density) and three common TRAPs (NO₂, black carbon, and ultra-fine particles.) This research highlights the public health implications of normative policy regimes like exclusionary zoning. These results can assist elected officials and planners in pursuing a more geographically distributive approach to increasing housing supply in the Seattle area, in order to minimize the TRAP exposure burden – and associated adverse health effects – faced by residents.

Eutrophication fuels toxic algal blooms that can harm biodiversity and human health. Phosphate is often the limiting nutrient in freshwater ecosystems and, when in excess, causes eutrophication. Our study compares urban lakes prone to algal blooms to rural lakes with fewer anthropogenic sources of pollution to better correlate nutrient dynamics of pacific northwest lakes to population density. We collected sediment and water samples from two lakes in the Seattle area and two lakes in a more remote setting, then measured phosphate uptake and release over time using ion chromatography. To determine the potential for the sediments to uptake phosphate, we placed air-dried sediment samples into a phosphate solution and measured the concentration over time. We also put the sediment in distilled water and measured the phosphate released from the sediment over a 24 hour time period. These two data sets allow us to quantify the capacity of sediment to store and release phosphate into the surrounding environment. Our research shows sediments from urban lakes release more phosphate and have a reduced ability to uptake nutrients from the water. This suggests that the lake will continue to eutrophy whereas the lakes more removed from human activity have a better ability to mitigate excess phosphates. This model for assessing the ability of sediment to store phosphate allows prediction of future eutrophication events.

Down syndrome (DS), a chromosomal condition that affects 1 in 700 babies in the United States, is associated with intellectual disability and delays in motor development. Early intervention can support motor and social development and participation in children with DS. While both Partial Body Weight Support (PBWS) systems and enriched play environments have been shown to enhance development and participation in children with DS, few studies have looked at these interventions in combination. The purpose of this study was to explore the benefits of a PBWS harness system within an enriched play environment on the mobility and social exploration of infants with DS. Our team hypothesized that PWBS would lead to a greater percentage of time engaged in both mobility and social behaviors during play. We conducted a multi-site clinical trial with 15 pre-walking infants with DS. The infants and their caregivers participated in 30-minute play sessions within an enriched 9’x9’ indoor play area with standardized toys 3 times a week for 6 weeks. Children used a PBWS harness for 3 of the 6 weeks, with harness/no harness order randomized for each participant. All play sessions were recorded and a subset of 6 participants’ data were analyzed using an adapted version of the CASPER-III coding scheme. Results showed that on average, infants showed a 5.28% increase in motor activity when using the PBWS harness compared to a 4.11% increase in motor activity when not using the harness. Additionally, when using the harness, infants on average showed an 8.99% increase in social activity whereas they showed a 0.07% decrease in social activity without the harness. These results show promise in facilitating greater access to mobility and exploration opportunities for children with DS using low-tech interventions such as PWBS in enriched play environments.