Association between recipient’s preexisting antibodies and allograft vasculopathy and mortality in heart transplant patients

Objectives: To evaluate the role of preexisting Angiotensin II receptor type I antibodies (AT1RAb) and anti-HLA antibodies in predicting mortality and cardiac allograft vasculopathy (CAV) among heart transplant patients. Methods: In this retrospective cohort study, we included 114 adults who received heart transplant from January 1st, 2007 to December 31, 2014 and were followed up at Nebraska Medicine. 48 hours pre-transplant sera sample were used to detect antibodies. A cutoff of 10UL/ml was used for AT1RAb positive and mean fluorescence intensity of 3,000 and 1,500 were used for anti HLA class I and class II, respectively. Patients were positive for composite antibodies if they were positive for anti-HLA, or AT1R antibodies. Survival analysis was conducted to compare the risk for mortality or CAV between antibody positive and negative groups. Result: Participants who had positive composite antibodies had higher probability of having CAV (p=0.05). Participants who were negative for AT1RAb trended toward a lower risk of mortality or developing CAV compared to AT1RAb positive counterparts. Conclusion: Positive status for any of anti-HLA or AT1RAb increased the risk of CAV. AT1RAb positivity is possibly linked with higher risk of death or developing CAV. Future study can focus on verifying these trends and the potential interaction effect between anti-HLA and AT1R antibodies

Whole-genome analysis of a daptomycin-susceptible Enterococcus faecium strain and its daptomycin-resistant variant arising during therapy

Development of daptomycin (DAP) resistance in Enterococcus faecalis has recently been associated with mutations in genes encoding proteins with two main functions: (i) control of the cell envelope stress response to antibiotics and antimicrobial peptides (LiaFSR system) and (ii) cell membrane phospholipid metabolism (glycerophosphoryl diester phosphodiesterase and cardiolipin synthase [cls]). However, the genetic bases for DAP resistance in Enterococcus faecium are unclear. We performed whole-genome comparative analysis of a clinical strain pair, DAP-susceptible E. faecium S447 and its DAP-resistant derivative R446, which was recovered from a single patient during DAP therapy. By comparative whole-genome sequencing, DAP resistance in R446 was associated with changes in 8 genes. Two of these genes encoded proteins involved in phospholipid metabolism: (i) an R218Q substitution in Cls and (ii) an A292G reversion in a putative cyclopropane fatty acid synthase enzyme. The DAP-resistant derivative R446 also exhibited an S333L substitution in the putative histidine kinase YycG, a member of the YycFG system, which, similar to LiaFSR, has been involved in cell envelope homeostasis and DAP resistance in other Gram-positive cocci. Additional changes identified in E. faecium R446 (DAP resistant) included two putative proteins involved in transport (one for carbohydrate and one for sulfate) and three enzymes predicted to play a role in general metabolism. Exchange of the “susceptible” cls allele from S447 for the “resistant” one belonging to R446 did not affect DAP susceptibility. Our results suggest that, apart from the LiaFSR system, the essential YycFG system is likely to be an important mediator of DAP resistance in some E. faecium strains

Características clínicas, microbiología y resultados de una cohorte de pacientes tratados con ceftolozane/tazobactam en centros de hospitalización de cuidados agudos, Houston, Texas, EE.UU

Antecedentes Ceftolozane/tazobactam es una combinación de β-lactámico/β-inhibidor de lactamasa con actividad contra una variedad de bacterias Gram-negativas, incluyendo Pseudomonas aeruginosa MDR. Este agente está aprobado para la neumonía bacteriana adquirida en el hospital y asociada a la ventilación mecánica. Sin embargo, la mayoría de los datos de resultados en el mundo real proceden de pequeñas cohortes observacionales. Por lo tanto, se trató de evaluar la utilización de ceftolozane/tazobactam en múltiples hospitales terciarios en Houston, TX, EE.UU.. Métodos Realizamos un estudio retrospectivo multicéntrico de pacientes que recibieron al menos 48 h de terapia con ceftolozano/tazobactam desde enero de 2016 hasta septiembre de 2019 en dos sistemas hospitalarios en Houston. Se recopilaron datos demográficos, clínicos y microbiológicos, incluido el aislado bacteriano infectante, cuando estaba disponible. El resultado primario fue el éxito clínico compuesto al alta hospitalaria. Los resultados secundarios incluyeron la mortalidad intrahospitalaria y la disposición clínica a los 14 y 30 días después del inicio de ceftolozane/tazobactam. Se utilizó un análisis de regresión logística multivariable para identificar los factores predictivos del resultado primario y la mortalidad. Los aislados recuperados se sometieron a pruebas de sensibilidad a ceftolozano/tazobactam y a WGS. Resultados Se incluyó a un total de 263 pacientes, y se alcanzó el éxito clínico compuesto en 185 pacientes (70,3%). La gravedad de la enfermedad fue el factor predictivo más consistente del éxito clínico. El tratamiento combinado con ceftolozane/tazobactam y otro agente Gram negativo activo se asoció a una reducción de las probabilidades de éxito clínico (OR 0,32; IC del 95%: 0,16-0,63). Se observó resistencia a ceftolozano/tazobactam en el 15,4% de los aislados disponibles para WGS; las mutaciones en ampC y ftsI fueron frecuentes pero no se agruparon con una ST concreta. Conclusiones La tasa de éxito clínico entre esta cohorte de pacientes tratados con ceftolozane/tazobactam fue similar en comparación con experiencias anteriores. Ceftolozane/tazobactam sigue siendo un agente alternativo para el tratamiento de aislados susceptibles de P. aeruginosaBackground Ceftolozane/tazobactam is a β-lactam/β-lactamase inhibitor combination with activity against a variety of Gram-negative bacteria, including MDR Pseudomonas aeruginosa. This agent is approved for hospital-acquired and ventilator-associated bacterial pneumonia. However, most real-world outcome data come from small observational cohorts. Thus, we sought to evaluate the utilization of ceftolozane/tazobactam at multiple tertiary hospitals in Houston, TX, USA. Methods We conducted a multicentre retrospective study of patients receiving at least 48 h of ceftolozane/tazobactam therapy from January 2016 through to September 2019 at two hospital systems in Houston. Demographic, clinical and microbiological data were collected, including the infecting bacterial isolate, when available. The primary outcome was composite clinical success at hospital discharge. Secondary outcomes included in-hospital mortality and clinical disposition at 14 and 30 days post ceftolozane/tazobactam initiation. Multivariable logistic regression analysis was used to identify predictors of the primary outcome and mortality. Recovered isolates were tested for susceptibility to ceftolozane/tazobactam and underwent WGS. Results A total of 263 patients were enrolled, and composite clinical success was achieved in 185 patients (70.3%). Severity of illness was the most consistent predictor of clinical success. Combination therapy with ceftolozane/tazobactam and another Gram-negative-active agent was associated with reduced odds of clinical success (OR 0.32, 95% CI 0.16–0.63). Resistance to ceftolozane/tazobactam was noted in 15.4% of isolates available for WGS; mutations in ampC and ftsI were common but did not cluster with a particular ST. Conclusions Clinical success rate among this patient cohort treated with ceftolozane/tazobactam was similar compared with previous experiences. Ceftolozane/tazobactam remains an alternative agent for treatment of susceptible isolates of P. aeruginosa

Antimicrobial sensing coupled with cell membrane remodeling mediates antibiotic resistance and virulence in Enterococcus faecalis.

Bacteria have developed several evolutionary strategies to protect their cell membranes (CMs) from the attack of antibiotics and antimicrobial peptides (AMPs) produced by the innate immune system, including remodeling of phospholipid content and localization. Multidrug-resistant Enterococcus faecalis, an opportunistic human pathogen, evolves resistance to the lipopeptide daptomycin and AMPs by diverting the antibiotic away from critical septal targets using CM anionic phospholipid redistribution. The LiaFSR stress response system regulates this CM remodeling via the LiaR response regulator by a previously unknown mechanism. Here, we characterize a LiaR-regulated protein, LiaX, that senses daptomycin or AMPs and triggers protective CM remodeling. LiaX is surface exposed, and in daptomycin-resistant clinical strains, both LiaX and the N-terminal domain alone are released into the extracellular milieu. The N-terminal domain of LiaX binds daptomycin and AMPs (such as human LL-37) and functions as an extracellular sentinel that activates the cell envelope stress response. The C-terminal domain of LiaX plays a role in inhibiting the LiaFSR system, and when this domain is absent, it leads to activation of anionic phospholipid redistribution. Strains that exhibit LiaX-mediated CM remodeling and AMP resistance show enhanced virulence in the Caenorhabditis elegans model, an effect that is abolished in animals lacking an innate immune pathway crucial for producing AMPs. In conclusion, we report a mechanism of antibiotic and AMP resistance that couples bacterial stress sensing to major changes in CM architecture, ultimately also affecting host-pathogen interactions

A single dose of ChAdOx1 Chik vaccine induces neutralising antibodies against four chikungunya virus lineages in a phase 1 clinical trial

Chikungunya virus (CHIKV) is a reemerging mosquito-borne virus that causes swift outbreaks. Major concerns are the persistent and disabling polyarthralgia in infected individuals. Here we present the results from a first-in-human trial of the candidate simian adenovirus vectored vaccine ChAdOx1 Chik, expressing the CHIKV full-length structural polyprotein (Capsid, E3, E2, 6k and E1). 24 adult healthy volunteers aged 18–50 years, were recruited in a dose escalation, open-label, nonrandomized and uncontrolled phase 1 trial (registry NCT03590392). Participants received a single intramuscular injection of ChAdOx1 Chik at one of the three preestablished dosages and were followed-up for 6 months. The primary objective was to assess safety and tolerability of ChAdOx1 Chik. The secondary objective was to assess the humoral and cellular immunogenicity. ChAdOx1 Chik was safe at all doses tested with no serious adverse reactions reported. The vast majority of solicited adverse events were mild or moderate, and self-limiting in nature. A single dose induced IgG and Tcell responses against the CHIKV structural antigens. Broadly neutralizing antibodies against the four CHIKV lineages were found in all participants and as early as 2 weeks after vaccination. In summary, ChAdOx1 Chik showed excellent safety, tolerability and 100% PRNT50 seroconversion after a single dose

Use of electrospinning to develop antimicrobial biodegradable multilayer systems: encapsulation of cinnamaldehyde and their physicochemical characterization

In this work, three active bio-based multilayer structures, using a polyhydroxybutyrate-co-valerate film with a valerate content of 8 % (PHBV8) as support, were developed. To this end, a zein interlayer with or without cinnamaldehyde (CNMA) was directly electrospun onto one side of the PHBV8 film and the following systems were developed: (1) without an outer layer; (2) using a PHBV8 film as outer layer; and (3) using an alginate-based film as outer layer. These multilayer structures were characterized in terms of water vapour and oxygen permeabilities, transparency, intermolecular arrangement and thermal properties. The antimicrobial activity of the active bio-based multilayer systems and the release of CNMA in a food simulant were also evaluated. Results showed that the presence of different outer layers reduced the transport properties and transparency of the multilayer films. The active bio-based multilayer systems showed antibacterial activity against Listeria monocytogenes being the multilayer structure prepared with CNMA and PHBV outer layers (PHBV + zein/CNMA + PHBV) the one that showed the greater antibacterial activity. The release of CNMA depended on the multilayer structures, where both Fick's and Case II transport-polymer relaxation explained the release of CNMA from the multilayer systems.Acknowledgments: Miguel A. Cerqueira (SFRH/BPD/72753/2010) andAnaI.Bourbon(SFRH/BD/73178/2010)arerecipientofafellowship from the Fundação para a Ciência e Tecnologia (FCT, POPH-QREN and FSE Portugal). J.L. Castro-Mayorga is supported by the Administrative Department of Science, Technology and Innovation (Colciencias) of Colombian Government. M. J. Fabra is a recipient of a Ramon y Cajal contract (RyC-2014-158) from the Spanish Ministry of Economy and Competitiveness. This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and of the Project RECI/BBB-EBI/ 0179/2012 (FCOMP-01-0124-FEDER-027462). The support of EU Cost Action MP1206 is gratefully acknowledged

The Osteopontin Level in Liver, Adipose Tissue and Serum Is Correlated with Fibrosis in Patients with Alcoholic Liver Disease

<div><h3>Background</h3><p>Osteopontin (OPN) plays an important role in the progression of chronic liver diseases. We aimed to quantify the liver, adipose tissue and serum levels of OPN in heavy alcohol drinkers and to compare them with the histological severity of hepatic inflammation and fibrosis.</p> <h3>Methodology/Principal Findings</h3><p>OPN was evaluated in the serum of a retrospective and prospective group of 109 and 95 heavy alcohol drinkers, respectively, in the liver of 34 patients from the retrospective group, and in the liver and adipose tissue from an additional group of 38 heavy alcohol drinkers. Serum levels of OPN increased slightly with hepatic inflammation and progressively with the severity of hepatic fibrosis. Hepatic OPN expression correlated with hepatic inflammation, fibrosis, TGFβ expression, neutrophils accumulation and with the serum OPN level. Interestingly, adipose tissue OPN expression also correlated with hepatic fibrosis even after 7 days of alcohol abstinence. The elevated serum OPN level was an independent risk factor in estimating significant (F≥2) fibrosis in a model combining alkaline phosphatase, albumin, hemoglobin, OPN and FibroMeter® levels. OPN had an area under the receiving operator curve that estimated significant fibrosis of 0.89 and 0.88 in the retrospective and prospective groups, respectively. OPN, Hyaluronate (AUROC: 0.88), total Cytokeratin 18 (AUROC: 0.83) and FibroMeter® (AUROC: 0.90) estimated significance to the same extent in the retrospective group. Finally, the serum OPN levels also correlated with hepatic fibrosis and estimated significant (F≥2) fibrosis in 86 patients with chronic hepatitis C, which suggested that its elevated level could be a general response to chronic liver injury.</p> <h3>Conclusion/Significance</h3><p>OPN increased in the liver, adipose tissue and serum with liver fibrosis in alcoholic patients. Further, OPN is a new relevant biomarker for significant liver fibrosis. OPN could thus be an important actor in the pathogenesis of this chronic liver disease.</p> </div

Contemporary Clinical and Molecular Epidemiology of Vancomycin-Resistant Enterococcal Bacteremia: A Prospective Multicenter Cohort Study (VENOUS I)

Background Vancomycin-resistant enterococci (VRE) are major therapeutic challenges. Prospective contemporary data characterizing the clinical and molecular epidemiology of VRE bloodstream infections (BSIs) are lacking. Methods The Vancomycin-Resistant Enterococcal BSI Outcomes Study (VENOUS I) is a prospective observational cohort of adult patients with enterococcal BSI in 11 US hospitals. We included patients with Enterococcus faecalis or Enterococcus faecium BSI with >= 1 follow-up blood culture(s) within 7 days and availability of isolate(s) for further characterization. The primary study outcome was in-hospital mortality. Secondary outcomes were mortality at days 4, 7, 10, 12, and 15 after index blood culture. A desirability of outcome ranking was constructed to assess the association of vancomycin resistance with outcomes. All index isolates were subjected to whole genome sequencing. Results Forty-two of 232 (18%) patients died in hospital and 39 (17%) exhibited microbiological failure (lack of clearance in the first 4 days). Neutropenia (hazard ratio [HR], 3.13), microbiological failure (HR, 2.4), VRE BSI (HR, 2.13), use of urinary catheter (HR, 1.85), and Pitt BSI score >= 2 (HR, 1.83) were significant predictors of in-hospital mortality. Microbiological failure was the strongest predictor of in-hospital mortality in patients with E faecium bacteremia (HR, 5.03). The impact of vancomycin resistance on mortality in our cohort changed throughout the course of hospitalization. Enterococcus faecalis sequence type 6 was a predominant multidrug-resistant lineage, whereas a heterogeneous genomic population of E faecium was identified. Conclusions Failure of early eradication of VRE from the bloodstream is a major factor associated with poor outcomes. Failure to eradicate enterococci from the bloodstream in the first 4 days after the index blood culture was the most consistent factor associated with increased risk of mortality. The association of vancomycin resistance with mortality changed throughout the course of the hospitalization

Connecting Variability in Global Transcription Rate to Mitochondrial Variability

The authors demonstrate a connection between variability in the rate of transcription and differences in cellular mitochondrial content

2018 Research & Innovation Day Program

A one day showcase of applied research, social innovation, scholarship projects and activities.https://first.fanshawec.ca/cri_cripublications/1005/thumbnail.jp