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Insights into complex nanopillar-bacteria interactions: Roles of nanotopography and bacterial surface proteins

Ishak MI, Jenkins J, Kulkarni S, Keller TF, Briscoe WH, Nobbs AH, et al.

J Colloid Interface Sci, 2021 Dec 15;604:91-103.
PMID: 34265695 DOI: 10.1016/j.jcis.2021.06.173

Nanopillared surfaces have emerged as a promising strategy to combat bacterial infections on medical devices. However, the mechanisms that underpin nanopillar-induced rupture of the bacterial cell membrane remain speculative. In this study, we have tested three medically relevant poly(ethylene terephthalate) (PET) nanopillared-surfaces with well-defined nanotopographies against both Gram-negative and Gram-positive bacteria. Focused ion beam scanning electron microscopy (FIB-SEM) and contact mechanics analysis were utilised to understand the nanobiophysical response of the bacterial cell envelope to a single nanopillar. Given their importance to bacterial adhesion, the contribution of bacterial surface proteins to nanotopography-mediated cell envelope damage was also investigated. We found that, whilst cell envelope deformation was affected by the nanopillar tip diameter, the nanopillar density affected bacterial metabolic activities. Moreover, three different types of bacterial cell envelope deformation were observed upon contact of bacteria with the nanopillared surfaces. These were attributed to bacterial responses to cell wall stresses resulting from the high intrinsic pressure caused by the engagement of nanopillars by bacterial surface proteins. Such influences of bacterial surface proteins on the antibacterial action of nanopillars have not been previously reported. Our findings will be valuable to the improved design and fabrication of effective antibacterial surfaces.
Resolving physical interactions between bacteria and nanotopographies with focused ion beam scanning electron microscopy

Jenkins J, Ishak MI, Eales M, Gholinia A, Kulkarni S, Keller TF, et al.

iScience, 2021 Jul 23;24(7):102818.
PMID: 34355148 DOI: 10.1016/j.isci.2021.102818

To robustly assess the antibacterial mechanisms of nanotopographies, it is critical to analyze the bacteria-nanotopography adhesion interface. Here, we utilize focused ion beam milling combined with scanning electron microscopy to generate three-dimensional reconstructions of Staphylococcus aureus or Escherichia coli interacting with nanotopographies. For the first time, 3D morphometric analysis has been exploited to quantify the intrinsic contact area between each nanostructure and the bacterial envelope, providing an objective framework from which to derive the possible antibacterial mechanisms of synthetic nanotopographies. Surfaces with nanostructure densities between 36 and 58 per μm2 and tip diameters between 27 and 50 nm mediated envelope deformation and penetration, while surfaces with higher nanostructure densities (137 per μm2) induced envelope penetration and mechanical rupture, leading to marked reductions in cell volume due to cytosolic leakage. On nanotopographies with densities of 8 per μm2 and tip diameters greater than 100 nm, bacteria predominantly adhered between nanostructures, resulting in cell impedance.
Fulltext Cross-continental comparison of safety and protection measures amongst urologists during COVID-19

de la Rosette J, Laguna P, Álvarez-Maestro M, Eto M, Mochtar CA, Albayrak S, et al.

Int J Urol, 2020 11;27(11):981-989.
PMID: 32772434 DOI: 10.1111/iju.14340

OBJECTIVES: To determine the well-being of urologists worldwide during the coronavirus disease 2019 pandemic, and whether they have adequate personal protective equipment knowledge and supplies appropriate to their clinical setting.
METHODS: Urologists worldwide completed a Société Internationale d'Urologie online survey from 16 April 2020 until 1 May 2020. Analysis was carried out to evaluate their knowledge about protecting themselves and others in the workplace, including their confidence in their ability to remain safe at work, and any regional differences.
RESULTS: There were 3488 respondents from 109 countries. Urologists who stated they were moderately comfortable that their work environment offers good protection against coronavirus disease 2019 showed a total mean satisfaction level of 5.99 (on a "0 = not at all" to "10 = very" scale). A large majority (86.33%) were confident about protecting themselves from coronavirus disease 2019 at work. However, only about one-third reported their institution provided the required personal protective equipment (35.78%), and nearly half indicated their hospital has or had limited personal protective equipment availability (48.08%). Worldwide, a large majority of respondents answered affirmatively for testing the healthcare team (83.09%). Approximately half of the respondents (52.85%) across all regions indicated that all surgical team members face an equal risk of contracting coronavirus disease 2019 (52.85%). Nearly one-third of respondents reported that they had experienced social avoidance (28.97%).
CONCLUSIONS: Our results show that urologists lack up-to-date knowledge of preferred protocols for personal protective equipment selection and use, social distancing, and coronavirus disease 2019 testing. These data can provide insights into functional domains from which other specialties could also benefit.
Fulltext A Public Health Research Agenda for Managing Infodemics: Methods and Results of the First WHO Infodemiology Conference

Calleja N, AbdAllah A, Abad N, Ahmed N, Albarracin D, Altieri E, et al.

JMIR Infodemiology, 2021 09 15;1(1):e30979.
PMID: 34604708 DOI: 10.2196/30979

Background: An infodemic is an overflow of information of varying quality that surges across digital and physical environments during an acute public health event. It leads to confusion, risk-taking, and behaviors that can harm health and lead to erosion of trust in health authorities and public health responses. Owing to the global scale and high stakes of the health emergency, responding to the infodemic related to the pandemic is particularly urgent. Building on diverse research disciplines and expanding the discipline of infodemiology, more evidence-based interventions are needed to design infodemic management interventions and tools and implement them by health emergency responders.
Objective: The World Health Organization organized the first global infodemiology conference, entirely online, during June and July 2020, with a follow-up process from August to October 2020, to review current multidisciplinary evidence, interventions, and practices that can be applied to the COVID-19 infodemic response. This resulted in the creation of a public health research agenda for managing infodemics.
Methods: As part of the conference, a structured expert judgment synthesis method was used to formulate a public health research agenda. A total of 110 participants represented diverse scientific disciplines from over 35 countries and global public health implementing partners. The conference used a laddered discussion sprint methodology by rotating participant teams, and a managed follow-up process was used to assemble a research agenda based on the discussion and structured expert feedback. This resulted in a five-workstream frame of the research agenda for infodemic management and 166 suggested research questions. The participants then ranked the questions for feasibility and expected public health impact. The expert consensus was summarized in a public health research agenda that included a list of priority research questions.
Results: The public health research agenda for infodemic management has five workstreams: (1) measuring and continuously monitoring the impact of infodemics during health emergencies; (2) detecting signals and understanding the spread and risk of infodemics; (3) responding and deploying interventions that mitigate and protect against infodemics and their harmful effects; (4) evaluating infodemic interventions and strengthening the resilience of individuals and communities to infodemics; and (5) promoting the development, adaptation, and application of interventions and toolkits for infodemic management. Each workstream identifies research questions and highlights 49 high priority research questions.
Conclusions: Public health authorities need to develop, validate, implement, and adapt tools and interventions for managing infodemics in acute public health events in ways that are appropriate for their countries and contexts. Infodemiology provides a scientific foundation to make this possible. This research agenda proposes a structured framework for targeted investment for the scientific community, policy makers, implementing organizations, and other stakeholders to consider.