Virulence behavior of uropathogenic Escherichia coli strains in the host model Caenorhabditis elegans

Urinary tract infections (UTIs) are among the most common bacterial infections in humans. Although a number of bacteria can cause UTIs, most cases are due to infection by uropathogenic Escherichia coli (UPEC). UPEC are a genetically heterogeneous group that exhibit several virulence factors associated with colonization and persistence of bacteria in the urinary tract. Caenorhabditis elegans is a tiny, free-living nematode found worldwide. Because many biological pathways are conserved in C. elegans and humans, the nematode has been increasingly used as a model organism to study virulence mechanisms of microbial infections and innate immunity. The virulence of UPEC strains, characterized for antimicrobial resistance, pathogenicity-related genes associated with virulence and phylogenetic group belonging was evaluated by measuring the survival of C. elegans exposed to pure cultures of these strains. Our results showed that urinary strains can kill the nematode and that the clinical isolate ECP110 was able to efficiently colonize the gut and to inhibit the host oxidative response to infection. Our data support that C. elegans, a free-living nematode found worldwide, could serve as an in vivo model to distinguish, among uropathogenic E. coli, different virulence behavior

Small Intestine Early Innate Immunity Response during Intestinal Colonization by Escherichia coli Depends on Its Extra-Intestinal Virulence Status

International audienceUropathogenic Escherichia coli (UPEC) strains live as commensals in the digestive tract of the host, but they can also initiate urinary tract infections. The aim of this work was to determine how a host detects the presence of a new UPEC strain in the digestive tract. Mice were orally challenged with UPEC strains 536 and CFT073, non-pathogenic strain K12 MG1655, and ΔPAI-536, an isogenic mutant of strain 536 lacking all 7 pathogenicity islands whose virulence is drastically attenuated. Intestinal colonization was measured, and cytokine expression was determined in various organs recovered from mice after oral challenge. UPEC strain 536 efficiently colonized the mouse digestive tract, and prior Enterobacteriaceae colonization was found to impact strain 536 colonization efficiency. An innate immune response, detected as the production of TNFα, IL-6 and IL-10 cytokines, was activated in the ileum 48 hours after oral challenge with strain 536, and returned to baseline within 8 days, without a drop in fecal pathogen load. Although inflammation was detected in the ileum, histology was normal at the time of cytokine peak. Comparison of cytokine secretion 48h after oral gavage with E. coli strain 536, CFT073, MG1655 or ΔPAI-536 showed that inflammation was more pronounced with UPECs than with non-pathogenic or attenuated strains. Pathogenicity islands also seemed to be involved in host detection, as IL-6 intestinal secretion was increased after administration of E. coli strain 536, but not after administration of ΔPAI-536. In conclusion, UPEC colonization of the mouse digestive tract activates acute phase inflammatory cytokine secretion but does not trigger any pathological changes, illustrating the opportunistic nature of UPECs. This digestive tract colonization model will be useful for studying the factors controlling the switch from commensalism to pathogenicity

Purification, crystallization and preliminary X-ray diffraction analysis of the Escherichia coli common pilus chaperone EcpB

This work was supported by a Wellcome Trust Investigator Award to SM (WT100280MA) and a project grant from the Leverhulme Trust (RPG-2012-559)

The StcE metalloprotease of enterohaemorrhagic Escherichia coli reduces the inner mucus layer and promotes adherence to human colonic epithelium ex vivo

Enterohaemorrhagic E. coli (EHEC) is a major foodborne pathogen and tightly adheres to human colonic epithelium by forming attaching/effacing lesions. To reach the epithelial surface, EHEC must penetrate the thick mucus layer protecting the colonic epithelium. In this study, we investigated how EHEC interacts with the intestinal mucus layer using mucin-producing LS174T colon carcinoma cells and human colonic mucosal biopsies. The level of EHEC binding and A/E lesion formation in LS174T cells was higher compared to mucin-deficient colon carcinoma cell lines, and initial adherence was independent of the presence of flagellin, E. coli common pilus or long polar fimbriae. While EHEC infection did not affect gene expression of secreted mucins, it resulted in reduced MUC2 glycoprotein levels. This effect was dependent on the catalytic activity of the secreted metalloprotease StcE which reduced the inner mucus layer and thereby promoted EHEC access and binding to the epithelium in vitro and ex vivo. Given the lack of efficient therapies against EHEC infection, StcE may represent a suitable target for future treatment and prevention strategies. This article is protected by copyright. All rights reserved

Journal Club: An Innovative Teaching Practice to Foster Peer Connection and Enhance Information Literacy Skills

This project aimed to better understand the impact and student experience of an innovative teaching strategy focused on information literacy (IL) for first-year undergraduate nursing students. Information literacy (IL) involves the development of a set of abilities essential for higher education learners, such as the ability to identify, critically evaluate, understand, and apply scholarly literature (ACRL 2013), yet studies often demonstrate that these IL skills are lacking and need further development (Bury 2016; Saunders 2012). Traditional methods of addressing this need center around stand-alone librarian-led IL sessions, which cannot provide the time or space needed to develop critical reading and reflection practices. Within our context of nursing, this is a common challenge; one study found that 40% of second-year nursing students have difficulty reading journal articles (Chaudoir et al. 2016), despite IL being an essential skill for nursing practice (Mitchell and Pereira-Edwards 2022). In an attempt to address learner needs, a course instructor and librarian teamed up. Journal clubs, used in practice settings to maintain currency and promote EBP behavior (Wilson et al. 2015), have been used successfully in other health education contexts (Steenbeek et al. 2009; Szucs et al. 2017; Thompson 2006). This application is referred to as evidence-based practice (EBP) and is an essential component of nursing practice. Having activities for undergraduate nursing students that instill EBP aims to ensure that it will be incorporated into practice after graduation (Mitchell and Pereira-Edwards 2022). Instead of the traditional librarian-led IL sessions, a first-year nursing course was redesigned to utilize a guided journal club approach to enhance the ability to seek, read, and interpret journal literature. Journal club activities took place over eight weeks, alternating guided activities with brief IL lessons, and culminated in a group journal club assignment. Students were placed in small groups based on an area of practice they wanted to learn more about. Activities were scaffolded starting with introducing a research database and basic literature searching strategies. As students progressed through the term’s journal club activities, they were asked to find articles related aligned with course topics and their area of practice, critique and present their articles to their group members, and then apply their interpretations. A survey was used to measure the impact of journal club on student IL self-efficacy, as measured through the validated Information Literacy Self-Efficacy Scale (ILSES) developed by Kurbanoglu et al. (2006). Initial findings support journal club as an effective modality to enhance students’ self-efficacy in specific areas of IL. Additionally, other valuable outcomes of this strategy were discovered. For example, students reported becoming more comfortable collaborating with peers and anecdotal reports showed students developed friendships with peers. This scaffolded journal club approach to discipline-specific IL learning would translate well to other contexts, particularly those that require a significant grounding in reading and understanding disciplinary research. The journal club activities are available at: https://tinyurl.com/JournalClubPosterISSOTL2022, or by contacting the authors. Click here to read the corresponding ISSOTL blog post

Escherichia coli: Great Diversity around a Common Core

The 2011 Escherichia coli outbreak in Germany, which resulted in more than 4,000 cases, including 908 cases of hemolytic-uremic syndrome (HUS) and at least 50 deaths, highlighted the genome plasticity of E. coli and the potential for new virulent strains to emerge. The analysis of 170 E. coli genome sequences for the presence of nine previously identified protective extraintestinal pathogenic E. coli antigens suggested the feasibility of a combination vaccine as a universal intervention against all pathogenic E. coli strains

Scaffolding Information Literacy Learning for Undergraduate Nursing Students: A Mixed-Method Exploration of Student IL Self-Efficacy

Abstract Purpose: Information literacy (IL) competency is an essential component of evidence-informed nursing practice. It is integral to introduce and develop core information literacy competencies for evidence-informed practice within undergraduate education programs. Research has shown undergraduate students may experience challenges with information literacy skills. More research to inform teaching methodologies that effectively enhance students’ skills and abilities, as well as their self-efficacy with these skills, is needed. This article describes an innovative teaching strategy, called journal club, which uses scaffolded learning activities in small groups over one semester. Methods: This mixed-methods research study used a non-experimental pre-post survey and was aimed at understanding the impact of the journal club strategy on students’ information literacy self-efficacy. The survey included the Information Literacy Self-Efficacy Scale (Kurbanoglu et al., 2006) and two open-ended questions in the post-survey. Results: A total of 37 participants, out of 42 potential participants, consented and responded to the pre-survey and 28 to the post-survey. Cohort-based descriptive statistics demonstrated a significant increase in overall scoring on the Information Literacy Self-Efficacy Scale from the pre-survey to the post-survey. Additionally, all relevant item measures from the tool showed statistically significant improvement. The open-ended questions were analyzed thematically, which resulted in the themes of recognition of personal growth, IL skill development, the opportunity to practise, time, the impact in the future, and relational engagement and benefits of the group. Conclusion: Overall, the findings of this study provide ample evidence that the journal club teaching strategy has positively enhanced students’ IL self-efficacy and will continue to be utilized in future offerings of the course. This strategy could be replicated in other contexts and content areas. Résumé Objectif : La maîtrise de l’information est une composante essentielle de la pratique infirmière fondée sur des données probantes. Il est essentiel d’apprivoiser et de développer des compétences informationnelles de base pour une pratique fondée sur des données probantes au sein des programmes de formation de premier cycle. Des études ont montré que les étudiantes et étudiants de premier cycle peuvent vivre des difficultés en lien avec les compétences de maîtrise de l’information. Des recherches supplémentaires sont nécessaires pour éclairer les stratégies d’enseignement qui améliorent efficacement le développement des capacités des étudiantes et étudiants, ainsi que leur connaissance de leurs propres efficacités en lien avec ces capacités. Cet article décrit une stratégie novatrice d’apprentissage, le club de lecture, qui utilise des activités d’apprentissage graduelles en petits groupes au cours d’un semestre. Méthodes : Cette étude de recherche non-expérimentale à méthodes mixtes utilisait un sondage pré et post intervention et visait à comprendre l’impact de la stratégie du club de lecture sur l’auto-efficacité des étudiantes et étudiants à maîtriser l’information. Le sondage comprenait l’échelle d’auto-efficacité à maîtriser l’information (Kurbanoglu et al., 2006) et deux questions ouvertes dans le sondage post-club de lecture. Résultats : Au total, 37 participants, sur 42 participants potentiels, ont consenti à l’étude et répondu au sondage pré et 28 au sondage post. Les statistiques descriptives basées sur les cohortes ont démontré une augmentation significative de la note globale sur l’échelle d’auto-efficacité en matière de maîtrise de l’information entre les sondages pré et post. De plus, tous les éléments pertinents mesurés par l’outil ont montré une amélioration statistiquement significative. Les questions ouvertes ont fait l’objet d’une analyse thématique, qui a abouti aux thèmes de la reconnaissance de la croissance personnelle, du développement de la compétence de maîtrise de l’information, de la possibilité de pratiquer, du temps, des répercussions à l’avenir, ainsi que de l’engagement relationnel et des avantages du groupe. Conclusion : Dans l’ensemble, les résultats de cette étude fournissent de nombreuses preuves que la stratégie d’enseignement du club de lecture a amélioré positivement l’auto-efficacité des étudiantes et étudiants en matière de maîtrise de l’information et continuera d’être utilisée dans les cours offerts dans le futur. Cette stratégie pourrait être reproduite dans d’autres contextes et domaines d’études

Combined dielectrophoretic and impedance system for on-chip controlled bacteria concentration: Application to Escherichia coli

The present paper reports a bacteria autonomous controlled concentrator prototype with a user-friendly interface for bench-top applications. It is based on a micro-fluidic lab-on-a-chip and its associated custom instrumentation, which consists in a dielectrophoretic actuator, to pre-concentrate the sample, and an impedance analyser, to measure concentrated bacteria levels. The system is composed by a single micro-fluidic chamber with interdigitated electrodes and a instrumentation with custom electronics. The prototype is supported by a real-time platform connected to a remote computer, which automatically controls the system and displays impedance data used to monitor the status of bacteria accumulation on-chip. The system automates the whole concentrating operation. Performance has been studied for controlled volumes of Escherichia coli (E. coli) samples injected into the micro-fluidic chip at constant flow rate of 10 μL/min. A media conductivity correcting protocol has been developed, as the preliminary results showed distortion of the impedance analyser measurement produced by bacterial media conductivity variations through time. With the correcting protocol, the measured impedance values were related to the quantity of bacteria concentrated with a correlation of 0.988 and a coefficient of variation of 3.1%. Feasibility of E. coli on-chip automated concentration, using the miniaturized system, has been demonstrated. Furthermore, the impedance monitoring protocol had been adjusted and optimized, to handle changes in the electrical properties of the bacteria media over time