Physiological adaptation in flagellar architecture improves Vibrio alginolyticus chemotaxis in complex environments.

Bacteria navigate natural habitats with a wide range of mechanical properties, from the ocean to the digestive tract and soil, by rotating helical flagella like propellers. Species differ in the number, position, and shape of their flagella, but the adaptive value of these flagellar architectures is unclear. Many species traverse multiple types of environments, such as pathogens inside and outside a host. We investigate the hypothesis that flagellar architectures mediate environment-specific benefits in the marine pathogen Vibrio alginolyticus which exhibits physiological adaptation to the mechanical environment. In addition to its single polar flagellum, the bacterium produces lateral flagella in environments that differ mechanically from water. These are known to facilitate surface motility and attachment. We use high-throughput 3D bacterial tracking to quantify chemotactic performance of both flagellar architectures in three archetypes of mechanical environments relevant to the bacterium's native habitats: water, polymer solutions, and hydrogels. We reveal that lateral flagella impede chemotaxis in water by lowering the swimming speed but improve chemotaxis in both types of complex environments. Statistical trajectory analysis reveals two distinct underlying behavioral mechanisms: In viscous solutions of the polymer PVP K90, lateral flagella increase the swimming speed. In agar hydrogels, lateral flagella improve overall chemotactic performance, despite lowering the swimming speed, by preventing trapping in pores. Our findings show that lateral flagella are multipurpose tools with a wide range of applications beyond surfaces. They implicate flagellar architecture as a mediator of environment-specific benefits and point to a rich space of bacterial navigation behaviors in complex environments.

Trends in Hospital Mortality for Uninsured Rural and Urban Populations, 2012-2016.

PURPOSE: Rural-urban health disparities have received increasing scrutiny as rural individuals continue to have worse health outcomes. However, little is known about how insurance status contributes to urban-rural disparities. This study characterizes how rural uninsured patients compare to the urban uninsured, determines whether rurality among the uninsured is associated with worse clinical outcomes, and examines how clinical outcomes based on rurality have changed over time. METHODS: We conducted a retrospective cohort study of the 2012-2016 National Inpatient Sample hospital discharge data including 1,478,613 uninsured patients, of which 233,816 were rural. Admissions were broken into 6 rurality categories. Logistic regression models were used to determine the independent association between rurality and hospital mortality. FINDINGS: Demographic and clinical characteristics differed significantly between rural and urban uninsured patients: rural patients were more often white, lived in places with lower median household income, and were more often admitted electively and transferred. Rurality was associated with significantly higher in-hospital mortality rates (1.44% vs 1.89%, OR 1.32, P < .001). This association strengthened after adjusting for medical comorbidities and hospital characteristics. Further, disparities between urban and rural mortality were found to be growing, with the gap almost doubling between 2012 and 2016. CONCLUSIONS: Rural and urban uninsured patients differed significantly, specifically in terms of race and median income. Among the uninsured, rurality was associated with higher in-hospital mortality, and the gap between urban and rural in-hospital mortality was widening. Our findings suggest the rural uninsured are a vulnerable population in need of informed, tailored policies to reduce these disparities.

Nutrition Education Services Described on National Cancer Institute (NCI)-Designated Cancer Center Websites.

For women diagnosed with breast cancer, healthy weight and enhanced nutrition may improve outcomes. The goal of this study is to examine the nutrition education services available on National Cancer Institute (NCI)-Designated Cancer Centers' websites. In 2017, websites of all 61 NCI-Designated Cancer Centers that provide adult clinical care were reviewed at least twice. Websites were analyzed for the existence and type of expert-directed nutrition education services for breast cancer survivors. Of the 61 websites analyzed, 49 (80%) provided information about nutrition education. Twenty (33%) included only nutrition counseling, three (5%) only nutrition classes, and 26 (42%) both counseling and classes. Forty-six websites included information about nutrition counseling; of these, 39 had an easily identifiable description. Thirty-seven class options were offered, 22% were specific to breast cancer, 16% to subgroups such as young women, 41% were nutrition-only classes, and 24% included skills education. Nutrition services are an important part of breast cancer treatment. This study demonstrated that most NCI-designated cancer centers offered counseling. However, the type of information that was offered varied and services were not always specific to patients with breast cancer. Further research is needed to confirm the presence of services, assess patient access, and demonstrate their efficacy in promoting optimal survivor outcomes.