Multidrug-Resistant Shigella sonnei Bacteremia among Persons Experiencing Homelessness, Vancouver, British Columbia, Canada.

Increased invasive bloodstream infections caused by multidrug resistant Shigella sonnei were noted in Vancouver, British Columbia, Canada, during 2021-2023. Whole-genome sequencing revealed clonal transmission of genotype 3.6.1.1.2 (CipR.MSM5) among persons experiencing homelessness. Improvements in identifying Shigella species, expanding treatment options for multidrug resistant infections, and developing public health partnerships are needed.

Shigella flexneri serotype 1 infections in men who have sex with men in Vancouver, Canada.

OBJECTIVES: Outbreaks of shigellosis have been documented in men who have sex with men (MSM), associated with interpersonal transmission and underlying HIV infection. We observed a rise in Shigella flexneri isolates identified in a downtown tertiary-care hospital laboratory located within the city centre community health area (CHA-1) of Vancouver, Canada. The objectives of this study were to evaluate clinical outcomes of shigellosis cases among MSM admitted to hospital and to evaluate trends in Shigella cases within Vancouver, Canada. METHODS: Adult rates of shigellosis were analysed by gender and health region, from 2005 to 2011, followed by retrospective chart review of all hospital laboratory-identified S. flexneri cases from 2008 to 2012. Serotyping and pulsed-field gel electrophoresis (PFGE) were performed on these isolates. RESULTS: Although shigellosis rates in men within CHA-1 did not change from 2005 to 2011 (range 33.4-68.5 per 100 000; P = 0.74), they were significantly higher than in other regions within the city of Vancouver (P ≤ 0.001) and the province of British Columbia (P ≤ 0.001). Shigella flexneri rates in men within CHA-1 increased significantly (range 2.3-51.4 per 100 000; P < 0.001), starting in 2008, and were higher than in other regions within Vancouver (P ≤ 0.01). Seventy-nine isolates of S. flexneri from 72 patients were identified by a single hospital laboratory. All patients were male and predominantly MSM (91.7%) and HIV-infected (86.1%), with most (92.6%) demonstrating CD4 counts ≥ 200 cells/µL. In total, 38.0% required hospitalization. Most (87.3%) had S. flexneri serotype 1 infection, with 72.9% of these representing a single PFGE pattern. CONCLUSIONS: We identified high levels of transmission of a primarily clonal strain of S. flexneri serotype 1 in our local MSM population, resulting in a substantial burden of illness and health care resource use secondary to hospital admissions.

Dual stimuli-responsive coating designed through layer-by-layer assembly of PAA-b-PNIPAM block copolymers for the control of protein adsorption.

In this paper, we describe the successful construction, characteristics and interaction with proteins of stimuli-responsive thin nanostructured films prepared by layer-by-layer (LbL) sequential assembly of PNIPAM-containing polyelectrolytes and PAH. PAA-b-PNIPAM block copolymers were synthesized in order to benefit from (i) the ionizable properties of PAA, to be involved in the LbL assembly, and (ii) the sensitivity of PNIPAM to temperature stimulus. The impact of parameters related to the structure and size of the macromolecules (their molecular weight and the relative degree of polymerization of PAA and PNIPAM), and the interaction with proteins under physico-chemical stimuli, such as pH and temperature, are carefully investigated. The incorporation of PAA-b-PNIPAM into multilayered films is shown to be successful whatever the block copolymer used, resulting in slightly thicker films than the corresponding (PAA/PAH)n film. Importantly, the protein adsorption studies demonstrate that it is possible to alter the adsorption behavior of proteins on (PAA-b-PNIPAM/PAH)n surfaces by varying the temperature and/or the pH of the medium, which seems to be intimately related to two key factors: (i) the ability of PNIPAM units to undergo conformational changes and (ii) the structural changes of the film made of weak polyelectrolytes. The simplicity of construction of these PNIPAM block copolymer-based LbL coatings on a large range of substrates, combined with their highly tunable features, make them ideal candidates to be employed for various biomedical applications requiring the control of protein adsorption.

Quartz crystal microbalance study of ionic strength and pH-dependent polymer conformation and protein adsorption/desorption on PAA, PEO, and mixed PEO/PAA brushes.

The conformation of polymer chains grafted on a substrate influences protein adsorption. In a previous study, adsorption/desorption of albumin was demonstrated on mixed poly(ethylene oxide) (PEO)/poly(acrylic acid) (PAA) brushes, triggered by solutions of adequate pH and ionic strength (I). In the present work, homolayers of PEO or PAA are submitted to saline solutions with pH from 3 to 9 and I from 10(-5) to 10(-1) M, and their conformation is evaluated in real time using quartz crystal microbalance with dissipation monitoring (QCM-D). Shrinkage/swelling of PAA chains and hydration and salt condensation in the brush are evidenced. The adsorption of human serum albumin (HSA) onto such brushes is also monitored in these different saline solutions, leading to a deep understanding of the influence of polymer chain conformation, modulated by pH and I, on protein adsorption. A detailed model of the conformation of PEO/PAA mixed brushes depending on pH and I is then proposed, providing a rationale for the identification of conditions for the successive adsorption and desorption of proteins on such mixed brushes. The adsorption/desorption of albumin on PEO/PAA is demonstrated using QCM-D.

Reduction in community-onset methicillin-resistant Staphylococcus aureus rates in an urban Canadian hospital setting.

Community-onset methicillin resistant Staphylococcus aureus (CO-MRSA) became a prominent cause of infection in North America in 2003, with a peak in the epidemic noted by multiple groups in the USA between 2005 and 2007. We reviewed rates of MRSA in two hospitals in Vancouver, Canada, to observe changes in epidemiology from 2003 to 2011. Episodes of emergency department (ED) MRSA bacteraemia and wounds were extracted from the laboratory database, with rates calculated per 10,000 ED visits. All cases were assumed to be community onset, as they were diagnosed in the ED. A peak in ED MRSA bacteraemias occurred in 2005, at 7·8/10,000 ED visits. By 2011, rates of ED bacteraemia declined significantly to 3·3/10,000 ED visits (P

Design of mixed PEO/PAA brushes with switchable properties toward protein adsorption.

Adsorption of proteins at interfaces is an ubiquitous phenomenon of prime importance. Layers of poly(ethylene oxide) (PEO) are widely used to repel proteins. Conversely, proteins were shown to adsorb deeply into brushes of poly(acrylic acid) (PAA), and their subsequent partial release could be triggered by a change of pH and/or ionic strength (I). Mixed brushes of these polymers are thus promising candidates to tune protein adsorption onto new smart surfaces. In this work, the synthesis of such mixed brushes was performed based on a "grafting to" approach, the two polymers being either grafted sequentially or simultaneously. Detailed characterization of the obtained brushes using static water contact angle measurements, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and polarization-modulation reflection-absorption infrared spectroscopy is presented. While sequential grafting of the two polymers for different reactions times did not give rise to a broad range of composition of mixed brushes, simultaneous grafting of the polymers from solutions with different compositions allows for the synthesis of a range of mixed brushes (mass fraction of PEO in the mixed brushes from 0.35 to 0.65). A key example is then chosen to illustrate the switchable behavior of a selected mixed PEO/PAA brush toward albumin adsorption. The adsorption behavior was monitored with a quartz crystal microbalance. The mixed brush could adsorb high amounts of albumin, but 86% of the adsorbed protein could then be desorbed upon pH and I change. The obtained properties are thus a combination of the ones of PEO and PAA, and a highly switchable behavior is observed toward protein adsorption.

Screening for methicillin-resistant Staphylococcus aureus (MRSA) in community-recruited injection drug users: are throat swabs necessary?

We examined and described colonization of MRSA in the anterior nares and throat from 184 community-recruited injection drug users. Thirty-seven (20%) were positive for MRSA: most (34, 92%) were carriers in the nares; while only three (8%) were carriers detected by throat swabs alone. The majority (29, 78%) of MRSA isolates were PVL positive.

Growth mechanism of confined polyelectrolyte multilayers in nanoporous templates.

We investigate the mechanism of polyelectrolyte multilayer (PEM) assembly in nanoporous templates with a view to synthesizing nanotubes or nanowires under optimal conditions. For this purpose, we focus on the effect of parameters related to the geometrical constraints (pore diameter), the size of the macromolecules (their molar mass and the ionic strength), and the interaction between the pore walls and the adsorbed chains (modulated by the ionic strength). Our results reveal the existence of two regimes in the mechanism of PEM growth: (i) the first regime is comparable to that observed on flat substrates, including the influence of ionic strength and (ii) the second regime, which is slower in terms of kinetics, results from the interconnection established between polyelectrolyte chains across the pores and leads to the formation of a dense gel. As a consequence, the diffusion of polyelectrolytes in nanopores becomes the controlling factor of PEM growth in this second regime. The dense gel, owing to its peculiar structure, enhances the formation of nanowires or of partially occluded nanotubes in some cases, depending on initial pore dimensions.

[IRM et myocardite infectieuse]. / IRM et myocardite infectieuse.

Over the past ten years, cardiac MRI has become an indispensable tool for acute myocarditis diagnosis. Under appropriate conditions, cardiac MRI may allow postponement of initial coronary angiography in many instances. The 2020 ESC guidelines give a class I recommendation to its use in the setting of MINOCA for differential diagnosis between acute myocardial infarction, myocarditis, Tako-Tsubo and other cardiac pathologies, in order to improve therapeutic management and follow-up. This article describes the technical characteristics of MRI in myocarditis (Lake Louise diagnostic criteria and criteria based on myocardial tissue mapping), the main differential diagnoses, the prognostic value and addresses the issue of myocarditis in the setting of COVID-19.

Enzyme-assisted mineralization of calcium phosphate: exploring confinement for the design of highly crystalline nano-objects.

In hard tissues of vertebrates, calcium phosphate (CaP) biomineralization is a fascinating process that combines specific physicochemical and biochemical reactions, resulting in the formation of extracellular matrices with elegant nanoarchitectures. Although several "biomimetic" strategies have been developed for the design of mineralized nanostructured biointerfaces, the control of the crystallization process remains complex. Herein, we report an innovative approach to overcome this challenge by generating, in situ, CaP precursors in a confined medium. For this purpose, we explore a combination of (i) the layer-by-layer assembly, (ii) the template-based method and (iii) the heterogeneous enzymatic catalysis. We show the possibility of embedding active alkaline phosphatase in a nanostructured multilayered film and inducing the nucleation and growth of CaP compounds under different conditions. Importantly, we demonstrate that the modulation of the crystal phase from spheroid-shaped amorphous CaP to crystalline platelet-shaped hydroxyapatite depends on the degree of confinement of active enzymes. This leads to the synthesis of highly anisotropic mineralized nanostructures that are mechanically stable and with controlled dimensions, composition and crystal phase. The present study provides a straightforward, yet powerful, way to design anisotropic nanostructured materials, including a self-supported framework, which may be used in broad biomedical applications.

[TAVI in women, very encouraging results]. / TAVI chez les femmes, des résultats très encourageants.

The population of elderly patients comprises a high percentage of women. This population is more vulnerable due to the presence of numerous comorbidities and is, therefore, particularly exposed to the risk of aortic valve degeneration, resulting in aortic valve stenosis whose symptoms are predictors of poor short-term outcomes. In the presence of symptomatic aortic stenosis, the recommended therapeutic option in this vulnerable population is the implementation of transcatheter aortic valve implantation, preferably via the femoral route. The outcomes of this procedure are better in women than in men despite a more frequent occurrence of vascular, bleeding and cerebral complications. Several hypotheses have been reported in the literature regarding the reasons for such differences. Among other reasons, it is likely that in female patients, the myocardium adjusts better to the occurrence of aortic stenosis and that recovery after valve treatment is also more optimal. Another explanation is the higher frequency of coronary artery disease in this older population. This has a considerable impact on the outcome even when coronary lesions are treated prior to valve implantation. There is still room for improvement and progress can be achieved by further reducing the size of the equipment used in order to decrease the diameter of the vascular access, and by continuing to simplify TAVI procedures. Less invasive techniques should result in decreased complication rates. In addition, dedicated studies should allow us to further improve our practice in this growing population of vulnerable patients.

Functionalization of magnetic nanowires by charged biopolymers.

We report on a facile method for the preparation of biocompatible and bioactive magnetic nanowires. The method consists of the direct deposition of polysaccharides by layer-by-layer (LbL) assembly onto a brush of metallic nanowires obtained by electrodeposition of the metal within the nanopores of an alumina template supported on a silicon wafer. Carboxymethylpullulan (CMP) and chitosan (CHI) multilayers were grown on brushes of Ni nanowires; subsequent grafting of an enzyme was performed by conjugating free amine side groups of chitosan with carboxylic groups of the enzyme. The nanowires are finally released by a gentle ultrasonic treatment. Transmission electron microscopy, electron energy-dispersive loss spectroscopy, and x-ray photoelectron spectroscopy indicate the formation of an homogeneous coating onto the nickel nanowires when one, two, or three CMP/CHI bilayers are deposited. This easy and efficient route to the biochemical functionalization of magnetic nanowires could find widespread use for the preparation of a broad range of nanowires with tailored surface properties.

[Transfemoral TAVI procedure in women: Minimally-invasive technique]. / Procédure de TAVI par voie fémorale chez la femme : technique minimaliste.

Demographic data point to a substantial proportion of women in the population of elderly patients with an increasing prevalence of aortic stenosis. Implantation of an aortic bioprosthesis via an endovascular approach known as Transcatheter aortic valve implantation (TAVI) in patients presenting with a symptomatic tight aortic stenosis (severe aortic stenosis) (AS) is an alternative therapeutic option to surgical aortic valve replacement in patients at high surgical risk or ineligible for surgery. The literature has shown that this technique seems to be particularly beneficial in female patients. In the Partner A trial, the 1-year mortality rate was significantly lower in women compared to their male counterparts. Other data revealed that although women have a higher risk of experiencing periprocedural complications (vascular events, bleeding and stroke), their outcome is good and often better than that of men. These results are continuously improving thanks to the enhancement of techniques and devices. In view of the published reports reflecting the increasing experience of the teams, it clearly appears that the simplification of TAVI procedures has resulted in improved outcomes. We report here the case of a patient treated by means of a "minimalist" approach to TAVI allowing a reduction of the risks inherent in the procedure. This simplified strategy relies on an optimal use of CT scan findings prior to TAVI. The procedure is carried out under local anesthesia and the main access site is sutured percutaneously (Proglides). The radial artery is used as a secondary access site. Contrast medium is diluted and stimulation is administered via the intraventricular guidewire. Direct stenting is performed when deemed feasible on the basis of CT scan results. Simplified procedures such as these contribute to the improvement of TAVI outcomes. However, further studies focusing on female patients are warranted in order to corroborate these findings.

Influence on intraocular pressure of anti-inflammatory treatments after selective laser trabeculoplasty.

INTRODUCTION: Selective laser trabeculoplasty (SLT) is an effective and safe procedure to lower intraocular pressure (IOP) in the management of open-angle glaucoma. The post-laser inflammatory reaction could be positively implicated in SLT efficacy and the relevance of postoperative use of topical anti-inflammatory remains controversial. The goal of this study is to determine the effect of various anti-inflammatory treatments on intraocular pressure and on side effects following SLT. MATERIAL AND METHODS: A prospective, randomized, double-blind study with a control group was conducted. Ninety-six eyes of 67 patients with primary open-angle glaucoma who underwent SLT were enrolled in this study between March 2009 and March 2012. Eyes recruited in the study were randomized to receive either prednisolone acetate 1%, diclofenac 0.1% or a placebo. The 3 treatments were administered 4 times a day for 5 days following SLT. The intraocular pressures were measured at regular intervals during the 6-months follow-up period. Side effects were also evaluated with a questionnaire as well as with the ocular exam. RESULTS: The analysis of the relative IOP decrease over the 6-months period revealed a significant difference between the time points of follow-up (P<0.0001), but no group effect (P=0.2980). No significant difference regarding anterior chamber inflammation and discomfort was observed between the 3 groups. CONCLUSION: There was no difference in intraocular pressure reduction, intraocular inflammation or ocular discomfort post-SLT when comparing the 3 treatment modalities.

Elastic modulus of polypyrrole nanotubes

The first measurements of the tensile elastic modulus of polypyrrole nanotubes are presented. The nanotubes were mechanically tested in three points bending using atomic force microscopy. The elastic tensile modulus was deduced from force-curve measurements on different nanotubes with outer diameter ranging between 35 and 160 nm. It is shown that the elastic modulus strongly increases when the thickness or outer diameter of polypyrrole nanotubes decreases.

Electrochemical synthesis of conjugated polymer wires and nanotubules

Two electrochemical methods designed for the synthesis of polypyrrole (PPy) wires and nanotubules are the topic of this paper. The concept that allows the morphology of PPy to be controlled is discussed for each method, and the performances of the two complementary techniques are compared in terms of dimension, shape and conductivity of PPy.

Quantitation of homocysteine in human plasma by capillary electrophoresis and laser-induced fluorescence detection.

Homocysteine (Hcy) represents a branching point between the transsulfuration and transmethylation pathway of methionine. A large increase of plasma concentration of Hcy is observed in patients with inherited hyperhomocysteinemia. A moderated increase (above 10 microM) is also observed in various pathological conditions, such as arterial occlusion, hypertension, hyperlipidemia and chronic renal failure. While amino acids were largely studied using capillary electrophoresis with UV or laser-induced fluorescence detection (LIF), thiol-amino acids were not. In this work we present a new approach for testing homocysteine in human plasma using CE-LIF and fluorescein isothiocyanate. The low fluorescence yield of the fluorescein thiocarbamyl (FTC) thiol-amino acids limits, probably, the sensitivity of the detection to 8 x 10(-10) M (instead of 10(-12) M for FTC-arginine).

Gene therapy in heart disease.

Application of gene therapy to the field of cardiovascular disorders has been the subject of intensive work over the recent period. Gene therapy for cardiovascular disorders is now fast developing with most therapies being devoted to the consequences (ischemia) rather than the causes of atherosclerotic diseases. Recent human clinical trials have shown that injection of naked DNA encoding vascular endothelial growth factor promotes collateral vessel development in patients with critical limb ischemia or chronic myocardial ischemia. Promising studies in animals have also fueled enthusiasm for treatment of human restenosis by gene therapy, but clinical applications are warranted. Application of gene transfer to other cardiovascular diseases will require the coordinated development of a variety of new technologies, as well as a better definition of cellular and gene targets.

Situational factors in cigarette smoking.

Situational factors related to smoking behavior in the natural environment were studied. Six subjects smoked all cigarettes over 10 days with a portable, electronic recording device which measured a number of frequency and time-based features of smoking. Subjects also coded activities and internal states associated with each cigarette smoked. Across subjects, there were considerable differences in the distribution of cigarettes smoked across the activity and internal states categories. Within subjects, all subjects showed variation in measures of smoking topography (number of puffs/cigarette, mean puff duration, total puff time/cigarette) as a function of situational variables. It did not appear that pharmacological factors could fully account for the substantial situational differences found. The results suggest that different factors may be involved in the control of different aspects of smoking topography.

Objective evaluation of aided thresholds using auditory steady-state responses.

Auditory steady-state responses to amplitude-modulated tones with modulation frequencies between 80 and 105 Hz can be recorded when multiple stimuli are presented simultaneously through a soundfield speaker and amplified using a hearing aid. Responses were recorded at carrier frequencies of 500, 1000, 2000, and 4000 Hz in a group of 35 hearing-impaired children using hearing aids. The physiologic responses were recorded at intensities close to the behavioral thresholds for sounds in the aided condition, with average differences between the physiologic and behavioral thresholds of 17, 13, 13, and 16 dB for carrier frequencies 500, 1000, 2000, and 4000 Hz. The technique shows great promise as a way to assess aided thresholds objectively in subjects who cannot reliably respond on behavioral testing.