Sidst opdateret 24.11.2018
Klik på linket nedenfor, tryk derefter Ctrl + C eller højreklik for at kopiere det.
Nedenfor kan du finde abstracts fra de nyeste artikler indenfor udvalgte internationale tidsskrifter med infektionsmedicinsk relevans. Du kan under "Yderligere søgekriterier" vælge tidsskrifter, hvor langt tilbage i tiden og rækkefølge.
Vælg eventuelt et eller flere søgeord til at afgrænse søgningen. Match, hvis mindst 1 ord er fundet. Benyt semikolon mellem hvert ord.
Vælg et eller flere tidsskrifter fra listen.
Alle | Ingen
Vælg hvor mange dage tilbage i tiden, der skal vælges artikler fra.
Vælg, hvordan resultaterne skal sorteres.
Søgeord (%s) valgt. Opdateret for 23 dage siden.88 emner vises.
Konze, S. A., Abraham, W.-R., Goethe, E., Surges, E., Kuypers, M. M. M., Hoeltig, D., Meens, J., Vogel, C., Stiesch, M., Valentin-Weigand, P., Gerlach, G.-F., Buettner, F. F. R.
Actinobacillus pleuropneumoniae is a capnophilic pathogen of the porcine respiratory tract lacking enzymes of the oxidative branch of the tricarboxylic acid (TCA) cycle. We previously claimed that A. pleuropneumoniae instead uses the reductive branch in order to generate energy and metabolites. Here we show that bicarbonate and oxaloacetate supported anaerobic growth of A. pleuropneumoniae. Isotope mass spectrometry revealed heterotrophic fixation of carbon from stable isotope labeled bicarbonate by A. pleuropneumoniae which was confirmed by nano-scale secondary ion mass spectrometry at a single cell level. By gas chromatography-combustion-isotope ratio mass spectrometry we could further show that the labeled carbon atom is mainly incorporated into the amino acids aspartate and lysine, which are derived from the TCA metabolite oxaloacetate. We therefore suggest that carbon fixation occurs at the interface of glycolysis and the reductive branch of the TCA cycle. The heme precursor -aminolevulinic acid supported growth of A. pleuropneumoniae similar to bicarbonate implying that anaplerotic carbon fixation is needed for heme synthesis. However, deletion of potential carbon fixing enzymes including PEP-carboxylase (PEPC), PEP-carboxykinase (PEPCK), malic enzyme and oxaloacetate decarboxylase as well as various combinations thereof did not affect carbon fixation. Interestingly, generation of a deletion mutant lacking all four enzymes was not possible suggesting that carbon fixation in A. pleuropneumoniae is an essential metabolic pathway controlled by a redundant set of enzymes. A double deletion mutant lacking PEPC and PEPCK was not impaired in carbon fixation in vitro, but showed reduction of virulence in a pig infection model.
Daniel Grinnan, Laszlo Farkas
American Journal of Respiratory and Critical Care Medicine, Volume 199, Issue 12, Page 1460-1461, June 15, 2019.
Melanie S. Vacchio, Thomas Ciucci, Yayi Gao, Masashi Watanabe, Mariah Balmaceno-Criss, Mitchell T. McGinty, Allan Huang, Qi Xiao, Cameron McConkey, Yongmei Zhao, Jyoti Shetty, Bao Tran, Marion Pepper, Golnaz Vahedi, Marc K. Jenkins, Dorian B. McGavern, Rémy Bosselut
The transcription factor Thpok is essential for the development of CD4+ T cells. Vacchio et al. show that in mature T cells, Thpok drives the expression of the transcriptional regulators Bcl6 and Maf to promote the differentiation of CD4+ T cells into T follicular helper (Tfh) cells, thus linking the CD4+ lineage to Tfh cell differentiation.
Mendez, J. M., Kolora, L. D., Lemon, J. S., Dupree, S. L., Keestra-Gounder, A. M.
Nucleotide-binding oligomerization domain 1 (NOD1) is an intracellular pattern-recognition receptor (PRR) responsible for sensing bacterial peptidoglycan fragments. Stimulation of NOD1 leads to a robust innate immune response via activation of the major transcription factor NF-B. In addition to peptidoglycan sensing, NOD1, and the closely related PRR NOD2, have been linked to inflammation by responding to the endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR). Here we show, that differential ER stress induction renders cells more susceptible to a Salmonella Typhimurium infection in a NOD1-dependent manner measured by increased NF-kB activation and cytokine expression. In HeLa57A cells, stably transfected with a NF-B::luciferase reporter, we show that cells undergoing ER stress induced by thapsigargin display a significant increase in NF-B activation in response to NOD1 stimulation by C12-iE-DAP and the S. Typhimurium effector protein SopE. Tunicamycin-induced ER stress had no effect on NOD1 stimulated NF-B activation. We further show that the mouse intestinal epithelial cell line MODE-K and RAW264.7 macrophages are more responsive to Salmonella infection when treated with thapsigargin but not with tunicamycin. These profound differences between thapsigargin and tunicamycin treated cells on inflammation suggest that different components downstream of the UPR contribute to NOD1 activation. We found that the NOD1-induced inflammatory response is dependent on protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) activation in conjunction with stimulation of the inositol triphosphate receptor (IP3R). Together, these results suggest that differential UPR activation makes cells more responsive to bacterial infections in a NOD1-dependent manner.
Richards, J. P., Cai, W., Zill, N. A., Zhang, W., Ojha, A. K.
Mycobacterium tuberculosis (Mtb) spontaneously grows at the air-medium interface forming pellicle biofilms, which harbor more drug tolerant persisters than planktonic cultures. The underlying basis for increased persisters in Mtb biofilms is unknown. Using a Tn-seq approach, we show here that multiple genes that are necessary for fitness of Mtb cells within biofilms, but not in planktonic cultures, are also implicated in tolerance of bacilli to a diverse set of stressors and antibiotics. Thus, development of Mtb biofilms appears to be associated with an enrichment of population, in which challenging growth conditions within biofilm architecture select for cells that maintain intrinsic tolerance to exogenous stresses including antibiotic exposure. We further observed that the intrinsic drug tolerance of constituent cells of a biofilm determines the frequency of persisters. These findings together allow us to propose that the selection of elite cells during biofilm development promotes the frequency of persisters. Furthermore, probing the possibility that the population enrichment is an outcome of unique environment within biofilms, we demonstrate biofilm-specific induction in the synthesis of isonitrile lipopeptides (INLP). Mutation analysis indicates that INLP is necessary for the architecture development of Mtb biofilms. In summary, the study offers an insight into persistence of Mtb biofilms under antibiotic exposure, while identifying INLP as a potential biomarker for further investigation of this phenomenon.
McCall, I. C., Shah, N., Govindan, A., Baquero, F., Levin, B. R.
Non-replicating bacteria are known to be (or at least commonly thought to be) refractory to antibiotics to which they are genetically susceptible. Here, we explore the sensitivity to killing by bactericidal antibiotics of three classes of non-replicating populations of planktonic bacteria; (1) stationary phase, when the concentration of resources and/or nutrients are too low to allow for population growth; (2) persisters, minority subpopulations of susceptible bacteria surviving exposure to bactericidal antibiotics; (3) antibiotic-static cells, bacteria exposed to antibiotics that prevent their replication but kill them slowly if at all, the so-called bacteriostatic drugs. Using experimental populations of Staphylococcus aureus Newman and Escherichia coli K12 (MG1655) and respectively 9 and 7 different bactericidal antibiotics, we estimate the rates at which these drugs kill these different types of non-replicating bacteria. Contrary to the common belief that bacteria that are non-replicating are refractory to antibiotic-mediated killing, all three types of non-replicating populations of these Gram-positive and Gram-negative bacteria are consistently killed by aminoglycosides and the peptide antibiotics, daptomycin and colistin, respectively. This result indicates that non-replicating cells, irrespectively of why they do not replicate, have an almost identical response to bactericidal antibiotics. We discuss the implications of these results to our understanding of the mechanisms of action of antibiotics and the possibility of adding a short-course of aminoglycosides or peptide antibiotics to conventional therapy of bacterial infections.
Pepper, Dominique J.; Sun, Junfeng; Cui, Xizhong; Welsh, Judith; Natanson, Charles; Eichacker, Peter Q.
To address three controversial components in the Centers for Medicare and Medicaid Service’s sepsis bundle for performance measure (SEP-1): antibiotics within 3 hours, a 30 mL/kg fluid infusion for all hypotensive patients, and repeat lactate measurements within 6 hours if initially elevated. We hypothesized that antibiotic- and fluid-focused bundles like SEP-1 would probably show benefit, but evidence supporting specific antibiotic timing, fluid dosing, or serial lactate requirements would not be concordant. Therefore, we performed a meta-analysis of studies of sepsis bundles like SEP-1.
PubMed, Embase, ClinicalTrials.gov through March 15, 2018.
Studies comparing survival in septic adults receiving versus not receiving antibiotic- and fluid-focused bundles.
Two investigators (D.J.P., P.Q.E.).
Seventeen observational studies (11,303 controls and 4,977 bundle subjects) met inclusion criteria. Bundles were associated with increased odds ratios of survival (odds ratio [95% CI]) in 15 studies with substantial heterogeneity (I2 = 61%; p < 0.01). Survival benefits were consistent in the five largest (1,697–12,486 patients per study) (1.20 [1.11–1.30]; I2 = 0%) and six medium-sized studies (167–1,029) (2.03 [1.52–2.71]; I2 = 8%) but not the six smallest (64–137) (1.25 [0.42–3.66]; I2 = 57%). Bundles were associated with similarly increased survival benefits whether requiring antibiotics within 1 hour (n = 7 studies) versus 3 hours (n = 8) versus no specified time (n = 2); or 30 mL/kg fluid (n = 7) versus another volume (≥ 2 L, n = 1; ≥ 20 mL/kg, n = 2; 1.5–2 L or 500 mL, n = 1 each; none specified, n = 4) (p = 0.19 for each comparison). In the only study employing serial lactate measurements, survival was not increased versus others. No study had a low risk of bias or assessed potential adverse bundle effects.
Available studies support the notion that antibiotic- and fluid-focused sepsis bundles like SEP-1 improve survival but do not demonstrate the superiority of any specific antibiotic time or fluid volume or of serial lactate measurements. Until strong reproducible evidence demonstrates the safety and benefit of any fixed requirement for these interventions, the present findings support the revision of SEP-1 to allow flexibility in treatment according to physician judgment.
The National Institutes of Health had no role in study design or data collection, analysis, or interpretation.
Drs. Pepper and Eichacker had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis, including and especially any adverse effects, and drafted the article. Dr. Pepper, Dr. Sun, Ms. Welsh, and Drs. Cui, Natanson, and Eichacker contributed substantially to the study design, data analysis, and interpretation, and approve the final version to be published. Dr. Sun, Ms. Welsh, and Drs. Cui and Natanson revised the article critically for important intellectual content.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website (http://journals.lww.com/ccmjournal).
Supported, in part, by National Institutes of Health intramural funding.
Drs. Pepper, Sun, Cui, Natanson, and Eichacker received support for article research from the National Institutes of Health. Drs. Pepper, Sun, and Cui, Ms. Welsh, and Dr. Eichacker disclosed government work.
Clinical Trial Registration numbers: International Prospective Register of Systematic Reviews (PROSPERO) 2017: CRD42017080258.
For information regarding this article, E-mail: email@example.com
Copyright © by 2019 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.
Bettina Winzeler, Nicole Cesana-Nigro, Julie Refardt, Deborah R Vogt, Cornelia Imber, Benedict Morin, Milica Popovic, Michelle Steinmetz, Clara O Sailer, Gabor Szinnai, Irina Chifu, Martin Fassnacht, Mirjam Christ-Crain
Arginine-stimulated copeptin measurements are an innovative test for diabetes insipidus with high diagnostic accuracy, and could be a simplified, novel, and safe diagnostic approach to diabetes insipidus in clinical practice.
Nakamura, I., Ohsumi, K., Takeda, S., Katsumata, K., Matsumoto, S., Akamatsu, S., Mitori, H., Nakai, T.
Current therapies against invasive pulmonary aspergillosis (IPA) have a limited cure rate. Given that a delay in treatment initiation may be fatal, a new drug with rapid -onset and potent antifungicidal activity is needed. The novel cyclic hexapeptide ASP2397 (currently known as VL-2397) exhibited antifungal activity against Aspergillus fumigatus (including azole-sensitive and azole-resistant isolates), A. terreus, and A. flavus at a MIC range of 1 to 4 μg/ml in human serum. Time-kill curve experiments showed that ASP2397 reduced germinated conidia of A. fumigatu by more than 1-log10 CFUs within 6 hours. In addition, ASP2397 inhibited hyphal elongation from germinated conidia of A. fumigatus, A. terreus, and A. flavus more rapidly than voriconazole. When treatment initiation was delayed in an IPA mouse model, ASP2397 had superior efficacy over posaconazole, with 100% survival and over 1-log10 CFU/g reduction in lung fungal burden. Histopathological investigation of lungs also showed that ASP2397 markedly suppressed disease progression. To clarify its mechanism of action, we generated a UV-induced mutant of A. fumigatus with low susceptibility to ASP2397. The mutant had a point mutation in the siderophore transporter gene sit1, which is absent in mammalian cells. These findings suggest that ASP2397 may improve clinical treatment options for IPA.
Ascher, Simon B.; Scherzer, Rebecca; Nishtala, Arvind; Jotwani, Vasantha; Grunfeld, Carl; Parikh, Chirag R.; Ng, Derek; Wang, Ruibin; Palella, Frank J.; Shlipak, Michael G.; Estrella, Michelle M.
Chronic kidney disease (CKD) occurs commonly among HIV-infected persons. Statins may delay CKD onset and progression via their cholesterol-lowering and pleiotropic effects.
Among 850 HIV-infected men from the Multicenter AIDS Cohort Study with stored urine samples (2009-2011), we evaluated cross-sectional associations of statin use with urine biomarkers of kidney damage (albumin-to-creatinine ratio [ACR], alpha-1-microglobulin, interleukin-18, kidney injury molecule-1, and procollagen type III N-terminal propeptide) using multivariable linear regression. We evaluated the longitudinal associations of statin use with annual change in estimated glomerular filtration rate by creatinine (eGFR) using linear mixed models, and with incident proteinuria and incident CKD (eGFR
Ersoy, S. C., Abdelhady, W., Li, L., Chambers, H. F., Xiong, Y. Q., Bayer, A. S.
Endovascular infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a major healthcare concern, especially infective endocarditis (IE). Standard antimicrobial susceptibility testing (AST) defines most MRSA strains as ‘resistant' to β-lactams, often leading to use of costly and/or toxic treatment regimens. In this investigation, five prototype MRSA strains, representing the range of genotypes in current clinical circulation, were studied. We identified two distinct MRSA phenotypes upon AST using standard media, with or without sodium bicarbonate (NaHCO3) supplementation: one highly susceptible to the anti-staphylococcal β-lactams, oxacillin and cefazolin (‘NaHCO3-responsive’) and one resistant to such agents (‘NaHCO3-nonresponsive’). These phenotypes accurately predicted clearance profiles of MRSA from target tissues in experimental MRSA IE treated with each β-lactam. Mechanistically, NaHCO3 reduced expression of two key genes involved in the MRSA phenotype, mecA and sarA, leading to decreased production of penicillin-binding protein (PBP) 2a (that mediates methicillin resistance), in NaHCO3-responsive (but not in NaHCO3-nonresponsive) strains. Moreover, both cefazolin and oxacillin synergistically killed NaHCO3-responsive strains in the presence of the host defense antimicrobial peptide (LL-37) in NaHCO3-supplemented media. These findings suggest that AST of MRSA strains in NaHCO3-containing media may potentially identify infections caused by NaHCO3-responsive strains that are appropriate for β-lactam therapy.
Joris Koetsveld, Alexander E. Platonov, Konstantin Kuleshov, Alex Wagemakers, Dieuwertje Hoornstra, Wim Ang, Sandor Szekeres, Gilian L.A. van Duijvendijk, Erol Fikrig, Monica E. Embers, Hein Sprong, Joppe W. Hovius
Borrelia miyamotoi is a relapsing fever Borrelia, transmitted by hard (Ixodes) ticks, which are also the main vector for Borrelia burgdorferi. A widely used test for serodiagnosis of Lyme borreliosis is an EIA based on the C6 peptide of the B. burgdorferi sl VlsE protein. We set out to study C6 reactivity upon infection with B. miyamotoi in a large well-characterized set of Borrelia miyamotoi disease (BMD) patient sera and in experimental murine infection.
Rebecca J Gordon, Michael A Levine
X-linked hypophosphataemia is the most common form of genetic rickets, and is characterised by low circulating concentrations of phosphorus that impair skeletal mineralisation and result in rickets in growing children and osteomalacia in adults.1 X-linked hypophosphataemia is caused by mutations in PHEX (phosphate-regulating endopeptidase homolog, X-linked), which encodes a transmembrane endopeptidase.2 Although the mechanism is uncertain, loss of PHEX leads to raised plasma concentrations of fibroblast growth factor 23 (FGF23), the best-characterised member of a family of phosphate-regulating hormones termed phosphatonins.
Swidergall M, Khalaji M, Solis N, et al.
AbstractBackgroundCandidalysin is a cytolytic peptide toxin secreted by Candida albicans hyphae and has significantly advanced our understanding of fungal pathogenesis. Candidalysin is critical for mucosal C albicans infections and is known to activate epithelial cells to induce downstream innate immune responses that are associated with protection or immunopathology during oral or vaginal infections. Furthermore, candidalysin activates the NLRP3 inflammasome and causes cytolysis in mononuclear phagocytes. However, the role of candidalysin in driving systemic infections is unknown.MethodsIn this study, using candidalysin-producing and candidalysin-deficient C albicans strains, we show that candidalysin activates mitogen-activated protein kinase (MAPK) signaling and chemokine secretion in endothelial cells in vitro.ResultsCandidalysin induces immune activation and neutrophil recruitment in vivo, and it promotes mortality in zebrafish and murine models of systemic fungal infection.ConclusionsThe data demonstrate a key role for candidalysin in neutrophil recruitment and fungal virulence during disseminated systemic C albicans infections.
This Medical Letter review summarizes the cardiovascular benefits and adverse effects of sodium-glucose co-transporter 2 (SGLT2) inhibitors (empagliflozin, canagliflozin) and glucagon-like peptide 1 (GLP-1) receptor agonists (liraglutide, semaglutide) in patients with type 2 diabetes at risk for cardiovascular disease.
Gupta, S., Thakur, J., Pal, S., Gupta, R., Mishra, D., Kumar, S., Yadav, K., Saini, A., Yavvari, P. S., Vedantham, M., Singh, A., Srivastava, A., Prasad, R., Bajaj, A.
Interkingdom polymicrobial biofilms formed by gram-positive Staphylococcus aureus and Candida albicans pose serious threats of chronic systemic infections due to absence of any common therapeutic target for their elimination. Herein, we present the structure-activity relationship (SAR) of membrane-targeting Cholic Acid Peptide conjugates (CAPs) against gram-positive bacterial and fungal strains. Structure-activity investigations validated by mechanistic studies witnessed that valine-glycine dipeptide-derived CAP 3 is most effective broad-spectrum antimicrobial against S. aureus and C. albicans. CAP 3 was able to degrade the pre-formed single species and polymicrobial biofilms formed by S. aureus and C. albicans, and CAP 3-coated materials could prevent the formation of biofilms. Murine wound and catheter infection models further confirmed the equally potent bactericidal and fungicidal effect of CAP 3 against bacterial, fungal and polymicrobial infections. Taken together, these results demonstrate that CAPs, as potential broad-spectrum antimicrobials, can effectively clear the frequently encountered polymicrobial infections and can be fine-tuned further for future applications.
Visitors to the Catch Your Breath temporary exhibition at the Royal College of Physicians (London, UK) start learning about breathlessness before they even reach the main displays—as they climb the steps in the central atrium to see the exhibition on the first floor, the staircase is peppered with facts about inhaling and exhaling, from “We take about 7 million breaths per year” and “The world record for holding your breath is an incredible 24 minutes”, through to “Spread out flat, the surface area of the lungs is about the same size as half a tennis court”, and “Breathlessness activates the same brain pathways as pain, hunger, and thirst.” Once visitors ascend, they are greeted with traditional museum display cases along either side of the walkway, with posters on the wall and audio-visual elements, including a television screen showing six short films and two listening posts, playing tracks relating to patients' and doctors' perspectives on breathlessness.
Vivax malaria is the predominant form of malaria outside Africa, affecting about 14 million people worldwide, with about 2.5 billion people exposed. Development of a Plasmodium vivax vaccine is a priority, and merozoite surface protein 7 (MSP-7) has been proposed as a plausible candidate. The P. vivax genome contains 12 MSP-7 genes, which contribute to erythrocyte invasion during blood-stage infection. Previous analysis of MSP-7 sequence diversity suggested that not all paralogs are functionally equivalent. To explore MSP-7 functional diversity, and to identify the best vaccine candidate within the family, MSP-7 expression and antigenicity during bloodstream infections were examined directly from clinical isolates.
Merozoite surface protein 7 gene expression was profiled using RNA-seq data from blood samples isolated from ten human patients with vivax malaria. Differential expression analysis and co-expression cluster analysis were used to relate PvMSP-7 expression to genetic markers of life cycle stage. Plasma from vivax malaria patients was also assayed using a custom peptide microarray to measure antibody responses against the coding regions of 12 MSP-7 paralogs.
Ten patients presented diverse transcriptional profiles that comprised four patient groups. Two MSP-7 paralogs, 7A and 7F, were expressed abundantly in all patients, while other MSP-7 genes were uniformly rare (e.g. 7J). MSP-7H and 7I were significantly more abundant in patient group 4 only, (two patients having experienced longer patency), and were co-expressed with a schizont-stage marker, while negatively associated with liver-stage and gametocyte-stage markers. Screening infections with a PvMSP-7 peptide array identified 13 linear B-cell epitopes in five MSP-7 paralogs that were recognized by plasma from all patients.
These results show that MSP-7 family members vary in expression profile during blood infections; MSP-7A and 7F are expressed throughout the intraerythrocytic development cycle, while expression of other paralogs is focused on the schizont. This may reflect developmental regulation, and potentially functional differentiation, within the gene family. The frequency of B-cell epitopes among paralogs also varies, with MSP-7A and 7L consistently the most immunogenic. Thus, MSP-7 paralogs cannot be assumed to have equal potential as vaccines. This analysis of clinical infections indicates that the most abundant and immunogenic paralog is MSP-7A.
The island of Anjouan (Comoros) is highly endemic for leprosy with an annual incidence of 5–10/10,000. In May/June, 2015 single-dose Rifampicin post-exposure prophylaxis (SDR-PEP) was administered to 269 close contacts of 70 leprosy-patients in four villages as a pilot programmatic intervention. Two years later we revisited the villages for follow-up investigations. The main aim of our study was to quantify spatial associations between reported leprosy cases before and after PEP implementation. A secondary aim was to assess the effect of this single round of SDR-PEP at the individual level.
We conducted door-to-door leprosy screening in all four villages in August/September, 2017. We screened all consenting individuals for leprosy and recorded geographic coordinates of their household. We also recorded whether they had received SDR-PEP and whether they had been diagnosed with leprosy, before or after the 2015 intervention. We fitted a Poisson model with leprosy as outcome and distance to the nearest pre-intervention case and SDR-PEP as predictors.
During the survey we found 114 new cases among 5760 contacts screened (2.0% prevalence), in addition to the 39 cases detected in the two preceding years. We found statistically significant associations of incident leprosy with physical distance to index cases ranging from 2.4 (95% confidence interval (95% CI) 1.5–3.6) for household contacts to 1.8 (95% CI 1.3–2.5) for those living at 1–25 m, compared to individuals living at ≥75 m.
The effect of SDR-PEP appeared protective but did not reach statistical significance due to the low numbers, with an incidence rate ratio (IRR) of 0.6 (95% CI 0.3–1.2) overall, and 0.5 (95% CI 0.2–1.3) when considering only household contacts.
This pilot demonstrated an increased risk of leprosy in contacts beyond the household, therefore a wider circle should be considered for chemoprophylaxis. Baseline surveys and extended contact definitions are essential for improving SDR-PEP effectiveness.
Falcipains are major cysteine proteases of Plasmodium falciparum involved in haemoglobin degradation and remain attractive anti-malarial drug targets. Several inhibitors against these proteases have been identified, yet none of them has been approved for malaria treatment. Other Plasmodium species also possess highly homologous proteins to falcipains. For selective therapeutic targeting, identification of sequence and structure differences with homologous human cathepsins is necessary. The substrate processing activity of these proteins is tightly controlled via a prodomain segment occluding the active site which is chopped under low pH conditions exposing the catalytic site. Current work characterizes these proteases to identify residues mediating the prodomain regulatory function for the design of peptide based anti-malarial inhibitors.
Sequence and structure variations between prodomain regions of plasmodial proteins and human cathepsins were determined using in silico approaches. Additionally, evolutionary clustering of these proteins was evaluated using phylogenetic analysis. High quality partial zymogen protein structures were modelled using homology modelling and residue interaction analysis performed between the prodomain segment and mature domain to identify key interacting residues between these two domains. The resulting information was used to determine short peptide sequences which could mimic the inherent regulatory function of the prodomain regions. Through flexible docking, the binding affinity of proposed peptides on the proteins studied was evaluated.
Sequence, evolutionary and motif analyses showed important differences between plasmodial and human proteins. Residue interaction analysis identified important residues crucial for maintaining prodomain integrity across the different proteins as well as the pro-segment responsible for inhibitory mechanism. Binding affinity of suggested peptides was highly dependent on their residue composition and length.
Despite the conserved structural and catalytic mechanism between human cathepsins and plasmodial proteases, current work revealed significant differences between the two protein groups which may provide valuable information for selective anti-malarial inhibitor development. Part of this study aimed to design peptide inhibitors based on endogenous inhibitory portions of protease prodomains as a novel aspect. Even though peptide inhibitors may not be practical solutions to malaria at this stage, the approach followed and results offer a promising means to find new malarial inhibitors.
Romero-Saavedra F, Laverde D, Kalfopoulou E, et al.
AbstractEnterococci have emerged as important nosocomial pathogens due to their resistance against the most commonly used antibiotics. Alternative treatments or prevention options are aimed at polysaccharides and surface-related proteins that play important roles in pathogenesis. Previously, we have shown that two Enterococcus faecium proteins, the secreted antigen A and the peptidyl-prolyl cis-trans isomerase, as well as the Enterococcus faecalis polysaccharide diheteroglycan are able to induce opsonic and cross-protective antibodies. Here, we evaluate the use of glycoconjugates consisting of these proteins and an enterococcal polysaccharide to develop a vaccine with broader strain coverage. Diheteroglycan was conjugated to these two enterococcal proteins. Rabbit sera raised against these glycoconjugates showed IgG titers towards the corresponding conjugate, as well as to the respective protein and carbohydrate antigens. Effective opsonophagocytic killing for the two sera was observed against different E. faecalis and E. faecium strains. ELISA against whole bacterial cells showed immune recognition of the sera towards 22 enterococcal strains. Moreover, sera conferred protection in a mouse infection model against E. faecalis and E. faecium strains. Our results suggest that these glycoconjugates are promising candidates for vaccine formulations with a broader coverage against these nosocomial pathogens and that the evaluated proteins are potential carrier proteins.
Scholzen, A., Richard, G., Moise, L., Hartman, E., Bleeker-Rovers, C. P., Reeves, P. M., Paul, S. R., Martin, W. D., De Groot, A. S., Poznansky, M. C., Sluder, A. E., Garritsen, A.
Infection with Coxiella burnetii, the causative agent of Q fever, can result in life-threatening persistent infection. Reactogenicity hinders worldwide implementation of the only licensed human Q fever vaccine. We previously demonstrated long-lived immunoreactivity in individuals with past symptomatic and asymptomatic Coxiella infection (convalescents) to promiscuous HLA-class II C. burnetii epitopes, providing the basis for a novel T-cell-targeted subunit vaccine. Here we investigated in a cohort of 22 individuals treated for persistent infection (chronic Q fever) whether they recognize the same set of epitopes, or distinct epitopes that could be candidates for a therapeutic vaccine or aid in the diagnosis of persistent infection.Individuals with chronic Q fever showed strong class II epitope-specific cultured ELISpot responses largely overlapping with the peptide repertoire identified previously for convalescents. Five additional peptides were recognized more frequently by chronic subjects, but there was no combination of epitopes uniquely recognized by or non-reactive in chronic Q fever subjects. Consistent with more recent/prolonged exposure, we found, however, stronger direct ex vivo responses to whole-cell C. burnetii and individual peptides in direct ELISpot than in convalescents.In conclusion, we have validated and expanded a previously published set of candidate epitopes for a novel T-cell targeted subunit Q fever vaccine in treated chronic Q fever patients and demonstrated that they successfully mounted a T-cell response comparable to that of convalescents. Finally, we demonstrate that individuals treated for chronic Q fever mount a broader ex vivo response to class II epitopes than convalescents, which could be explored for diagnostic purposes.
Early diagnosis of gastric tuberculosis is often challenging because the disease is very rare and its clinical manifestation is nonspecific and misleading. To raise the awareness and emphasize early diagnosis of gastric tuberculosis, we present a case of gastric tuberculosis secondary to pleural and pulmonary tuberculosis.
A 26-year-old woman complained gastric pain for 1 month but showed no other symptoms, who had no previous exposure to tuberculosis.Gastric stromal tumor was originally suspected. However, the pathology of her gastroscopic biopsy of the gastric lesion showed granulomatous lesions and caseating necrosis. Gene sequencing of the biopsy specimen identified deoxyribonucleic acid fragment of Mycobacterium tuberculosis. Chest computed tomography scan revealed nodular shadows in the lesser curvature soft tissue of the stomach, patchy densities and calcified nodular shadows in the upper right lung, bilateral pleural thickening, and calcified pleural nodules. Thus, the diagnosis was gastric tuberculosis secondary to pulmonary and pleural tuberculosis. The patient was hospitalized and treated with the antituberculosis therapy for 1 week. After discharged from the hospital, the patient continued routine antituberculosis therapy for 18 months and was follow-up was normal.Literature search found 22 cases of gastric tuberculosis reported from 2000 to 2016. Review of the 22 cases suggested that polymerase chain reaction has been increasingly used in the recent years in addition to the conventional histopathological and bacteriological approaches.
Clinical presentation of gastric tuberculosis is not specific.When granuloma or caseation is detected on biopsy in patients who are suspected of having gastric malignancy or acid peptic diseases, polymerase chain reaction for Mycobacterium tuberculosis could be used as an available and sensitive diagnostic test in addition to pathology, acid-fast bacilli smear staining and culture.
Malhotra, S., Hayes, D., Wozniak, D. J.
In human pathophysiology, the clash between microbial infection and host immunity contributes to multiple diseases. Cystic fibrosis (CF) is a classical example of this phenomenon, wherein a dysfunctional, hyperinflammatory immune response combined with chronic pulmonary infections wreak havoc upon the airway, leading to a disease course of substantial morbidity and shortened life span. Pseudomonas aeruginosa is an opportunistic pathogen that commonly infects the CF lung, promoting an accelerated decline of pulmonary function. Importantly, P. aeruginosa exhibits significant resistance to innate immune effectors and to antibiotics, in part, by expressing specific virulence factors (e.g., antioxidants and exopolysaccharides) and by acquiring adaptive mutations during chronic infection. In an effort to review our current understanding of the host-pathogen interface driving CF pulmonary disease, we discuss (i) the progression of disease within the primitive CF lung, specifically focusing on the role of host versus bacterial factors; (ii) critical, neutrophil-derived innate immune effectors that are implicated in CF pulmonary disease, including reactive oxygen species (ROS) and antimicrobial peptides (e.g., LL-37); (iii) P. aeruginosa virulence factors and adaptive mutations that enable evasion of the host response; and (iv) ongoing work examining the distribution and colocalization of host and bacterial factors within distinct anatomical niches of the CF lung.
Teasdale, Chloe A.; Yuengling, Katharine A.; Mutiti, Anthony; Arpadi, Stephen; Nxele, Mahlubandile; Pepeta, Lungile; Mogashoa, Mary; Rivadeneira, Emilia D.; Abrams, Elaine J.
We report data from an observational cohort of South African children living with HIV
Rogovskyy, A. S., Caoili, S. E. C., Ionov, Y., Piontkivska, H., Skums, P., Tsyvina, V., Zelikovsky, A., Waghela, S. D.
Lyme disease (LD), the most prevalent vector-borne illness in the United States and Europe, is caused by Borreliella burgdorferi (Bb). No vaccine is available for humans. Dogmatically, Bb can establish a persistent infection in the mammalian host (e.g., mice) due to a surface antigen, VlsE. This antigenically variable protein allows the spirochete to continually evade borreliacidal antibodies. However, our recent study has shown that the Bb spirochete is effectively cleared by anti-Bb antibodies of New Zealand White rabbits despite the surface expression of VlsE. Besides homologous protection, the rabbit antibodies also cross-protect against heterologous Bb and significantly reduced pathology of LD arthritis in persistently infected mice. Thus, this finding that NZW rabbits develop a unique repertoire of very potent antibodies targeting the protective surface epitopes, despite abundant VlsE, prompted us to identify specificities of the rabbit protective antibodies and their respective targets. By applying subtractive reverse vaccinology, which involved random peptide phage display libraries coupled with the next generation sequencing and our computational algorithms, repertoires of non-protective (early) and protective (late) rabbit antibodies were identified and directly compared. Consequently, putative surface epitopes that are unique to the rabbit protective sera have been mapped. Importantly, the relevance of newly identified protection-associated epitopes for their surface exposure has been strongly supported by prior empirical studies. This study is significant because it now allows us to systematically test the putative epitopes for their protective efficacy with an ultimate goal of selecting the most efficacious targets for development of a long-awaited LD vaccine.
Blais, N., Somers, D., Faubert, D., Labbe, S., Castado, C., Ysebaert, C., Gagnon, L.-P., Champagne, J., Gagne, M., Martin, D.
Non-typeable Haemophilus influenzae (NTHi) is a pathogen known for being a frequent cause of acute otitis media in children and respiratory tract infections in adults with chronic obstructive pulmonary disease. In the present study, a vaccine antigen has been developed based on the fusion of two known NTHi adhesive proteins, Protein E (PE) and pilin subunit (PilA). The quality of the combined antigen was investigated through functional, biophysical and structural analyses. It was shown that PE and PilA individual structures are not modified in the PE-PilA fusion and that PE-PilA assembles as a dimer in solution, reflecting PE dimerization. PE-PilA was found to bind vitronectin in ELISA, as isolated PE does. Disulfide bridges were conserved and homogeneous, which was determined by peptide mapping and Top-down analysis on PE, PilA and PE-PilA molecules. Finally, the PE-PilA crystal showed a PE entity with a 3D-structure similar to that of recently published isolated PE, while the structure of the PilA entity was similar to that of a 3D-model elaborated from two other type 4 pilin subunits.Taken together, our observations suggest that the two tethered proteins behave independently within the chimeric molecule and display structures similar to the respective isolated antigens, which are important characteristics for eliciting an optimal antibody-mediated immunity. PE and PilA can thus be further developed as a single fusion protein in a vaccine perspective, in the knowledge that tethering the two antigens does not perceptibly compromise the structural attributes offered by the individual antigens.
Woodburn, K. W., Clemens, L. E., Jaynes, J., Joubert, L.-M., Botha, A., Nazik, H., Stevens, D. A.
Background: Recurrent Vulvovaginal Candidiasis (RVVC) is a widespread chronic infection that has a substantial negative impact on work and quality of life. The development of antimicrobial resistance and biofilm formation are speculated to contribute to Candida pathogenicity and treatment ineffectiveness. Designed antimicrobial peptides (dAMPs) are chemically modified from endogenous antimicrobial peptides that provide the first line of defense against pathogens. The goal here is to identify a dAMP for the topical treatment of RVVC.Methods: The dAMP minimum inhibitory concentrations (MICs) were determined for 46 fluconazole-susceptible and fluconazole-resistant Candida spp. clinical isolates. The possibility of inducing dAMP drug resistance, and comparison of dAMP and fluconazole activity against preformed Candida biofilm and biofilm formation were evaluated. Assessment of mammalian cell viability was determined using bioluminescent human keratinocytes. The dAMP effect on fungus was probed via scanning electron microscopy and topically applied dAMP activity was evaluated in a rodent VVC infection model.Results: dAMPs demonstrated broad-spectrum antimicrobial activity against common causative clinical Candida isolates, reduced preformed biofilm and inhibited biofilm formation. An evaluated dAMP did not induce resistance after repeated exposure of C. tropicalis. The dAMPs were selective for Candida cells with limited mammalian cytotoxicity with substantial activity in a rodent VVC model.Conclusions: dAMPs are described with potent antifungal and anti-biofilm activity, likely direct membrane action with selectivity for Candida cells, with limited resistance development. Combined with activity in a rodent VVC model, the data support clinical evaluation of dAMPs for topical treatment of VCC and recurrent VVC infections.
Fischer, D., Gessner, G., Fill, T. P., Barnett, R., Tron, K., Dornblut, K., Kloss, F., Stallforth, P., Hube, B., Heinemann, S. H., Hertweck, C., Scherlach, K., Brunke, S.
Jagaricin is a lipopeptide produced by the bacterial mushroom pathogen Janthinobacterium agaricidamnosum, the causative agent of mushroom soft rot disease. Apart from causing lesions in mushrooms, jagaricin is a potent antifungal active against human-pathogenic fungi.We show that jagaricin acts by impairing membrane integrity, resulting in a rapid flux of ions, including Ca2+, into susceptible target cells. Accordingly, the calcineurin pathway is required for jagaricin tolerance in the fungal pathogen Candida albicans. Transcriptional profiling of pathogenic yeasts further revealed that jagaricin triggers cell wall strengthening, general shutdown of membrane potential-driven transport, and upregulation of lipid transporters – linking cell envelope integrity to jagaricin action and resistance.Whereas jagaricin shows haemolytic effects, it exhibited either no or low plant toxicity at concentrations at which the growth of prevalent phytopathogenic fungi is inhibited. Therefore, jagaricin may have potential for agricultural applications. The action of jagaricin as a membrane-disrupting antifungal is promising, but would require modifications for use in humans.
Lin, J., Lau, G. W.
Streptococcus pneumoniae (pneumococcus) causes multiple infectious diseases. The pneumococcal competence system facilitates genetic transformation, spreads antibiotic resistance and contributes to virulence. The DNA processing protein A (DprA) regulates the exit of pneumococcus from the competent state. Previously, we have shown that DprA is important in both bacteremia and pneumonia infections. Here, we examined the mechanisms of virulence attenuation in dprA. When compared to the parental wild-type D39, dprA enters the competent state when exposed to lower concentrations of the competence stimulating peptide CSP1. dprA overexpresses ComM, which delays cell separation after division. Additionally, dprA overexpresses allolytic factors LytA, CbpD and CibAB, and is more susceptible to detergent-triggered lysis. Disabling of the competent state-specific induction of ComM and allolytic factors compensated for the virulence loss in dprA, suggesting that overexpression of these factors contribute to virulence attenuation. Finally, dprA fails to down-regulate the expression of multiple competence-regulated genes, leading the excessive energy consumption. Collectively, these results indicate that inability to properly exit the competent state disrupts multiple cellular processes that cause virulence attenuation in dprA.
Sara Porfírio, Russell W. Carlson, Parastoo Azadi
A mistake was present in an earlier version of the review article ‘Elucidating Peptidoglycan Structure: An Analytical Toolset’ by Porfírio et al. Some linkages between amino acids were incorrectly represented in Figure 2. All minor structural errors have been amended and a corrected figure has been provided.
A monoclonal antibody that the FDA approved last year to prevent chronic and episodic migraine has now received approval to treat episodic cluster headache in adults. The drug blocks calcitonin gene-related peptide ligand—a potent vasodilator that modulates nociceptive trigeminal neurons involved in the pathophysiology of cluster headaches. Patients can self-inject galcanezumab, marketed as Emgality.
Rappo, U., Dunne, M. W., Puttagunta, S., Baldassarre, J. S., Su, S., Desai-Krieger, D., Inoue, M.
Dalbavancin is a lipoglycopeptide antibiotic with a prolonged half-life. A Phase 1 study assessed dalbavancin levels in epithelial lining fluid (ELF) in 35 healthy adults using ELF bronchial microsampling up to 168 hrs after 1500 mg dalbavancin. The penetration of dalbavancin into ELF was 36%. ELF levels of dalbavancin exceeded the MIC90 of S. pneumoniae and S. aureus for ≥ 7 days.
Adam V Benjafield, Najib T Ayas, Peter R Eastwood, Raphael Heinzer, Mary S M Ip, Mary J Morrell, Carlos M Nunez, Sanjay R Patel, Thomas Penzel, Jean-Louis D Pépin, Paul E Peppard, Sanjeev Sinha, Sergio Tufik, Kate Valentine, Atul Malhotra
To our knowledge, this is the first study to report global prevalence of obstructive sleep apnoea; with almost 1 billion people affected, and with prevalence exceeding 50% in some countries, effective diagnostic and treatment strategies are needed to minimise the negative health impacts and to maximise cost-effectiveness.
Babak Mokhlesi, Juan Fernando Masa, Jan L. Brozek, Indira Gurubhagavatula, Patrick B. Murphy, Amanda J. Piper, Aiman Tulaimat, Majid Afshar, Jay S. Balachandran, Raed A. Dweik, Ronald R. Grunstein, Nicholas Hart, Roop Kaw, Geraldo Lorenzi-Filho, Sushmita Pamidi, Bhakti K. Patel, Susheel P. Patil, Jean Louis Pépin, Israa Soghier, Maximiliano Tamae Kakazu, Mihaela Teodorescu
American Journal of Respiratory and Critical Care Medicine, Volume 200, Issue 3, Page e6-e24, August 1, 2019.
Sultan, A. S., Vila, T., Hefni, E., Karlsson, A. J., Jabra-Rizk, M. A.
Oral candidiasis (OC) caused by the fungal pathogen Candida albicans is the most common opportunistic infection in immunocompromised populations. The dramatic increase in resistance to common antifungal agents has emphasized the importance of identifying alternative therapeutic options. Antimicrobial peptides have emerged as promising drug candidates due to their antimicrobial properties; specifically, histatin-5 (Hst-5), a peptide naturally produced and secreted by human salivary glands, has demonstrated potent activity against C. albicans. However, as we previously demonstrated vulnerability for Hst-5 to proteolysis by C. albicans proteolytic enzymes at specific amino-acid residues, a new variant (K11R-K17R) was designed with amino-acid substitutions at the identified cleavage sites. The new resistant peptide demonstrated no cytotoxicity to erythrocytes and human oral keratinocytes. To evaluate the potential of the new peptide for clinical application, we utilized our FDA-approved polymer-based bioadhesive hydrogel as a delivery system and developed a therapeutic formulation specifically designed for oral topical application. The new formulation was demonstrated to be effective against C. albicans strains resistant to the traditional antifungals and the in vitro therapeutic efficacy was found to be comparable to that of the common topical antifungal agents in clinical use. Importantly, in addition to its antifungal properties, our findings also demonstrated that the new peptide variant induces cell proliferation and rapid cell migration of human oral keratinocytes indicative of wound healing properties. The findings from this study support the progression of the novel formulation as a therapeutic agent against oral candidiasis, as well as a therapeutic modality for promoting wound healing.
A combination of visual and auditory stimulation reduced brain amyloid-β peptide (Aβ) and improved memory in mouse models of Alzheimer disease (AD), according to recent preclinical research.
Christopher M. Gentile, Anton V. Borovjagin, Jillian R. Richter, Aditi H. Jani, Hongju Wu, Kurt R. Zinn, Jason M. Warram
by Christopher M. Gentile, Anton V. Borovjagin, Jillian R. Richter, Aditi H. Jani, Hongju Wu, Kurt R. Zinn, Jason M. Warram
Background A major obstacle to using recombinant adenoviral vectors in gene therapy is the natural ability of human adenovirus to activate the classical and alternate complement pathways. These innate immune responses contribute to hepatic adenoviral uptake following systemic delivery and enhance the humoral immune responses associated with adenoviral infection. Methods A recombinant Ad5 vector was genetically modified to display a peptide sequence (“rH17d’”), a known inhibitor of the classical complement pathway. The replication-defective vectors Ad5.HVR2-rH17d’ and Ad5.HVR5-rH17d’ were constructed by engineering the rH17d’ peptide into the hypervariable region (HVR)-2 or HVR5 of their major capsid protein hexon. Control Ad5 vectors were created by incorporation of a 6-histidine (His6)-insert in either HVR2 or HVR5 (Ad5.HVR2-His6 and Ad5.HVR5-His6, respectively). All vectors encoded CMV promoter-controlled firefly luciferase (Luc). The four vectors were evaluated in TIB76 mouse liver cells and immunocompetent mice to compare infectivity and liver sequestration, respectively. Results In vitro studies demonstrated that preincubation of all the Ad5 vectors with fresh serum significantly increased their gene transfer relative to preincubation with PBS except Ad5.HVR5-rH17d’, whose infectivity of liver cells showed no serum-mediated enhancement. In line with that, mice injected with Ad5.HVR2-rH17d’ or Ad5.HVR5-rH17d’ showed significantly lower luciferase expression levels in the liver as compared to the respective control vectors, whereas efficiency of tumor transduction by rH17d’ and His6 vectors following their intratumoral injection was similar. Conclusions Displaying a complement-inhibiting peptide on the Ad5 capsid surface by genetic modification of the hexon protein could be a suitable strategy for reducing Ad5 liver tropism (Ad5 sequestration by liver), which may be applicable to other gene therapy vectors with natural liver tropism.
Accumulating evidence suggests that infections by herpesviruses might be closely linked to Alzheimer's disease (AD). Pathological hallmarks of AD brains include senile plaques induced by amyloid β peptide (Aβ) in the extracellular space and intracellular neurofibrillary tangles (NFTs) consisting of phosphorylated tau protein. The prevailing hypothesis for the mechanism of AD is amyloid cascade reaction. Recent studies revealed that infections by herpesviruses induce the similar pathological hallmarks of AD, including Aβ production, phosphorylation of tau (P‐tau), oxidative stress, neuroinflammation, etc. Aβ peptide is regarded as one of the antimicrobial peptides, which inhibits HSV‐1 replication. In the elderly, reactivation of herpesviruses might act as an initiator for amyloid cascade reaction in vulnerable individuals, triggering the neurofibrillary formation of phosphorylated tau and inducing oxidative stress and neuroinflammation, which can further contribute to the accumulation of Aβ and P‐tau by impairing mitochondria and autophagosome. Epidemiological studies have shown AD susceptibility genes, such as APOE‐ε4 allele, are highly linked to infections by herpesviruses. Interestingly, anti‐herpesviral therapy significantly reduced the risk of AD in a large population study. Given that herpesviruses are arguably the most prevalent opportunistic pathogens and often reactivate in the elderly, it is reasonable to argue reactivation of herpesviruses might be major culprits for initiating AD in individuals carrying AD susceptibility genes. In this review, we summarize epidemiological and molecular evidence that support for a hypothesis of herpesviral infections and antimicrobial protection in the development of AD, and discuss the implications for future prevention and treatment of the disease.
Johnson, Kelly A.; Hessol, Nancy A.; Kohn, Robert; Nguyen, Trang Q.; Mara, Elise S.; Hsu, Ling; Scheer, Susan; Cohen, Stephanie E.
The comparative effectiveness of pre and post-exposure prophylaxis (PrEP and PEP) for men who have sex with men (MSM) is unclear.
We conducted a case-control study of MSM who were initially HIV-uninfected during 9/1/2012 – 6/30/2016 at San Francisco’s only municipal sexually transmitted diseases (STD) clinic.
Each case was matched with up to three controls based on age, baseline visit date, and follow-up time. The primary dependent variable was HIV seroconversion; the primary independent variable was exposure to PrEP, PEP, or neither. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals.
Of 638 MSM (161 cases, 477 controls), 137 reported ever taking PrEP, 98 reported taking PEP only, and 403 took neither. PrEP takers had more non-HIV STDs during the analysis (72.3% vs. 55.1% vs. 42.4% p
Zmuda, F., Sastry, L., Shepherd, S. M., Jones, D., Scott, A., Craggs, P. D., Cortes, A., Gray, D. W., Torrie, L. S., De Rycker, M.
Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, is a potentially life-threatening condition that has become a global issue. Current treatment is limited to two medicines that require prolonged dosing and are associated with multiple side effects, which often lead to treatment discontinuation and failure. One way to address these shortcomings is through target-based drug discovery on validated T. cruzi protein targets. One such target is the proteasome, which plays a crucial role in protein degradation and turnover, through chymotrypsin-, trypsin-, and caspase-like catalytic activities. In order to initiate a proteasome drug discovery programme, we isolated proteasomes from T. cruzi epimastigotes and characterized their activity using a commercially available glow-like luminescence-based assay. We developed a high-throughput biochemical assay for the chymotrypsin-like activity of the T. cruzi proteasome, which was found to be sensitive, specific, and robust, but prone to luminescence technology interference. To mitigate this, we have also developed a counter-screen assay that identifies potential interferers at the level of both the luciferase enzyme reporter and the mechanism responsible for a glow-like response. Interestingly, we also found that the peptide substrate for chymotrypsin-like proteasome activity was not specific, and was likely partially turned over by other catalytic sites of the protein. Finally, we utilised these biochemical tools to screen 18,098 compounds exploring diverse drug-like chemical space, which allowed us to identify 39 hits that were active in the primary screening assay (pIC50 ≥4) and inactive in the counter-screen assay (pIC50
Volk C, Burgdorf S, Edwardson G, et al.
AbstractIntroductionPatient IL-1β and IL-10 responses early in the course of Staphylococcus aureus bacteremia (SaB) are associated with bacteremia duration and mortality. We hypothesized that these responses vary depending on choice of antimicrobial therapy, with particular interest in knowing whether the superior performance of -lactams may be linked to key cytokine signaling pathways.MethodsThree medical centers included 59 patients with SaB (47 MRSA, 12 MSSA) from 2015-2017. In the first 48 h, patients were treated with either a β-lactam (n=24), including oxacillin, cefazolin, or ceftaroline, or a glyco-/lipopeptide (n=35), i.e. vancomycin or daptomycin (VAN/DAP). Patient sera from days 1, 3 and 7 were assayed for IL-1β and IL-10 by ELISA and compared using Mann-Whitney U.ResultsOn day 1 of presentation, IL-10 was elevated in patients with outcomes of mortality (P=0.008) and persistent bacteremia (P=0.034), while no difference occurred in IL-1β. Regarding treatment groups, IL-1β and IL-10 was similar at presentation prior to receiving an antibiotic. Patients treated with β-lactam had higher IL-1β on day 3 (median +5.6 pg/mL; P=0.007) and day 7 (+10.9 pg/ml; P=0.016). Ex vivo, the addition of IL-1 receptor antagonist anakinra to whole blood reduced staphylococcal killing, supporting a functional significance of the host IL-1β response in SaB clearance. β-lactam treated patients had sharper declines in IL-10 than VAN/DAP treated patients at days 3 and 7.
Ming S, Li M, Wu M, et al.
AbstractImmunosuppression contributes to the mortality of sepsis. However, the underlying mechanism remains unclear. In the present study, we investigated the role of inhibitory receptor immunoglobulin-like transcript 5 (ILT5) in sepsis. We first screened the expression of ILT family members, and found that ILT5 was dramatically up-regulated in the peripheral blood mononuclear cells (PBMCs) from sepsis patients vs healthy donors. Knockdown of ILT5 by siRNA increased bacterial killing and reactive oxygen species (ROS) production in THP-1 and RAW264.7 cells. Moreover, ILT5-expressing monocytes/macrophages exhibited lower expression of antigen-presenting molecules including MHC-II and CD80. In the in vitro co-culture system with monocytes/macrophages, blockage of ILT5 facilitated Th1 proliferation and differentiation of CD4+T cells. Furthermore, in vivo experiment demonstrated that pretreatment with ILT5 blocking peptide improved the survival and pulmonary pathology of septic mice. Together, our study identified ILT5 as an immunosuppressive regulator during sepsis, which may provide potential therapeutic strategy for sepsis.
Diaz, Y., Govasli, M. L., Zegeye, E. D., Sommerfelt, H., Steinsland, H., Puntervoll, P.
Infection with enterotoxigenic Escherichia coli (ETEC) is a common cause of childhood diarrhea in low- and middle-income countries, as well as of diarrhea among travelers to these countries. In children, ETEC strains secreting the heat-stable toxin (ST) are the most pathogenic, and there are ongoing efforts to develop vaccines that target ST. One important challenge for ST vaccine development is to construct immunogens that do not elicit antibodies that cross-react with guanylin and uroguanylin, which are endogenous peptides involved in regulating the activity of the guanylate cyclase-C (GC-C) receptor. We immunized mice with both human ST (STh) and porcine ST (STp) chemically coupled to bovine serum albumin, and the resulting sera neutralized the toxic activities of both STh and STp. This suggests that a vaccine based on either ST variant can confer cross-protection. However, several anti-STh and anti-STp sera cross-reacted with the endogenous peptides, suggesting that the ST sequence must be altered to reduce the risk of unwanted cross-reactivity. Epitope mapping of four monoclonal anti-STh and six anti-STp antibodies, all of which neutralized both STh and STp, revealed that most epitopes appear to have at least one amino acid residue shared with guanylin or uroguanylin. Despite this, only one monoclonal antibody displayed demonstrable cross-reactivity to the endogenous peptides, suggesting that targeted mutations of a limited number of ST residues may be sufficient to obtain a safe ST-based vaccine.
Kerry Murphy, Marla J. Keller, Kathryn Anastos, Shada Sinclair, J. Cooper Devlin, Qiuhu Shi, Donald R. Hoover, Brian Starkman, Jamie McGillick, Caroline Mullis, Howard Minkoff, Maria Gloria Dominguez-Bello, Betsy C. Herold
by Kerry Murphy, Marla J. Keller, Kathryn Anastos, Shada Sinclair, J. Cooper Devlin, Qiuhu Shi, Donald R. Hoover, Brian Starkman, Jamie McGillick, Caroline Mullis, Howard Minkoff, Maria Gloria Dominguez-Bello, Betsy C. Herold
Background Reproductive aging may impact the vaginal microbiome and genital tract mucosal immune environment and contribute to genital tract health in women living with and at-risk for HIV infection. Methods A cross-sectional study of 102 HIV+ (51 premenopausal, 51 postmenopausal) and 39 HIV-uninfected (HIV-) (20 premenopausal, 19 postmenopausal) women was performed in Bronx and Brooklyn, NY. Cervicovaginal lavage (CVL) was collected for quantification of innate antimicrobial activity against E. coli, HSV-2 and HIV and immune mediators by Luminex and ELISA. Microbiome studies by qPCR and 16S rRNA sequencing were performed on vaginal swabs. Results HIV+ postmenopausal compared to premenopausal participants had lower median E. coli bactericidal activity (41% vs. 62%, p = 0.001), lower median gene copies of Lactobacillus crispatus (p = 0.005) and Lactobacillus iners (p = 0.019), lower proportions of Lactobacillus iners, higher proportions of Gardnerella and Atopobium vaginae and lower levels of human beta defensins (HBD-2, HBD-3) and secretory leukocyte protease inhibitor (SLPI), p
Huang, Y., Hang, X., Jiang, X., Zeng, L., Jia, J., Xie, Y., Li, F., Bi, H.
Helicobacter pylori is a major global pathogen and its infection represents a key factor in the etiology of various gastric diseases including gastritis, peptic ulcers and gastric carcinoma. The efficacy of current standard treatment for H. pylori infection including two broad-spectrum antibiotics is compromised by toxicity toward gut microbiota and development of drug resistance, which will likely only be resolved through novel and selective antibacterial strategies. Here, we synthesized a small molecule, Zinc linolenate (ZnLla), and investigated its therapeutic potential for the treatment of H. pylori infection. ZnLla showed effective antibacterial activity against standard strains and drug-resistant clinical isolates of H. pylori in vitro with no development of resistance during continuous serial passaging. The mechanisms of ZnLla action against H. pylori involved disruption of bacterial cell membranes and generation of reactive oxygen species. In mouse models of multi-drug resistant H. pylori infection, ZnLla showed comparable and superior in vivo killing efficacy to the triple therapy approach, as a monotherapy and a combined therapy with omeprazole, respectively. Moreover, ZnLla treatment induces negligible toxicity against normal tissues and causes minimal effects on both the diversity and composition of the murine gut microbiota. Thus the high degree of selectivity of ZnLla for H. pylori provides an attractive candidate for novel targeted anti-H. pylori treatment.
Torrens G, Sánchez-Diener I, Jordana-Lluch E, et al.
AbstractBackgroundSearching for new strategies to defeat Pseudomonas aeruginosa is of paramount importance. Previous works in vitro showed that peptidoglycan recycling blockade disables the AmpC-dependent resistance and enhances the susceptibility against cell-wall targeting immunity. Our objective was to validate these findings in murine models.MethodsWildtype PAO1, the recycling-defective mutants in AmpG and NagZ, the AmpC hyper-producer dacB mutant, and their combinations were used to cause systemic/respiratory infections in mice. Their survival, bacterial burden, inflammation level and effectiveness of ceftazidime or sub-therapeutic colistin to treat the infections were assessed.ResultsThe inactivation of AmpG or NagZ significantly attenuated the virulence, in terms of mice mortality, bacterial load and inflammation. When inactivating these genes in the dacB defective background, the β–lactam resistance phenotype was abolished, disabling the emergence of ceftazidime-resistant mutants, and restoring ceftazidime for treatment. Sub-therapeutic colistin was shown to efficiently clear the infection caused by the recycling-defective strains, likely due to the combined effect with the mice cell-wall targeting immunity.ConclusionsThis study brings us one step closer to new therapies intended to disable P. aeruginosa AmpC-mediated resistance and dampen its virulence, and strongly support the interest of developing efficient AmpG and/or NagZ inhibitors.
Zhujun Ao, Lijun Wang, Emelissa J. Mendoza, Keding Cheng, Wenjun Zhu, Eric A. Cohen, Keith Fowke, Xiangguo Qiu, Gary Kobinger, Xiaojian Yao
by Zhujun Ao, Lijun Wang, Emelissa J. Mendoza, Keding Cheng, Wenjun Zhu, Eric A. Cohen, Keith Fowke, Xiangguo Qiu, Gary Kobinger, Xiaojian Yao
The development of an effective vaccine against HIV infection remains a global priority. Dendritic cell (DC)-based HIV immunotherapeutic vaccine is a promising approach which aims at optimizing the HIV-specific immune response using primed DCs to promote and enhance both the cellular and humoral arms of immunity. Since the Ebola virus envelope glycoprotein (EboGP) has strong DC-targeting ability, we investigated whether EboGP is able to direct HIV particles towards DCs efficiently and promote potent HIV-specific immune responses. Our results indicate that the incorporation of EboGP into non-replicating virus-like particles (VLPs) enhances their ability to target human monocyte-derived dendritic cells (MDDCs) and monocyte-derived macrophages (MDMs). Also, a mucin-like domain deleted EboGP (EboGPΔM) can further enhanced the MDDCs and MDMs-targeting ability. Furthermore, we investigated the effect of EboGP on HIV immunogenicity in mice, and the results revealed a significantly stronger HIV-specific humoral immune response when immunized with EboGP-pseudotyped HIV VLPs compared with those immunized with HIV VLPs. Splenocytes harvested from mice immunized with EboGP-pseudotyped HIV VLPs secreted increased levels of macrophage inflammatory proteins-1α (MIP-1α) and IL-4 upon stimulation with HIV Env and/or Gag peptides compared with those harvested from mice immunized with HIV VLPs. Collectively, this study provides evidence for the first time that the incorporation of EboGP in HIV VLPs can facilitate DC and macrophage targeting and induce more potent immune responses against HIV.
Louis, L., Clark, M., Wise, M. C., Glennie, N., Wong, A., Broderick, K., Uzonna, J., Weiner, D. B., Scott, P.
Vaccination remains one of the greatest medical breakthroughs in human history, and has resulted in near eradication of many former lethal diseases in many countries including the complete eradication of smallpox. However, there remain a number of diseases for which there are no or only partially effective vaccines. There are numerous hurdles in vaccine development, of which knowing the appropriate immune response to target is one of them. Recently, tissue resident T cells have been shown to mediate high levels of protection for several infections, although the best ways to induce these cells is still unclear. Here we compare the ability to generate skin resident T cells in sites distant from the immunization site following intramuscular and intradermal injection using optimized synthetic DNA vaccines. We found that mice immunized intradermally with a synthetic consensus DNA HIV Envelope vaccine by electroporation (EP) are better able to maintain durable antigen specific cellular responses in the skin compared to mice immunized by the intramuscular route. We extended these studies by delivering a synDNA vaccine encoding Leishmania Glycosomal Phosphoenolpyruvate Carboxykinase (PEPCK) by EP, and again found that the intradermal route was superior to the intramuscular route for generating skin resident PEPCK specific T cells. When challenged with Leishmania major (L. major) parasites, we observed that mice immunized intradermally exhibited significant protection, while mice immunized intramuscularly did not. The protection seen in intradermally vaccinated mice support the viability of this platform to not only generate skin resident T cells, but also to promote durable protective immune responses at relevant tissues sites.
Raz, A., Serrano, A., Hernandez, A., Euler, C. W., Fischetti, V. A.
Multi-drug resistance (MDR) is rapidly increasing in prevalence among isolates of the opportunistic pathogen Pseudomonas aeruginosa, leaving few treatment options. Phage lysins are cell wall hydrolases that have a demonstrated therapeutic potential against Gram-positive pathogens, however the outer membrane of Gram-negative bacteria prevents most lysins from reaching the peptidoglycan, making them less effective as therapeutics. Nevertheless, a few lysins from gram-negative phage can penetrate the bacterial outer membrane, aided by an amphipathic tail found in the molecule's termini. In this work we took a phylogenetic approach to systematically identify those lysins from P. aeruginosa phage that would be most effective therapeutically. We isolated and performed preliminary characterization of 16 lysins, and chose two lysins, PlyPa03 and PlyPa91, which exhibited >5-log killing activity against P. aeruginosa and other Gram-negative pathogens (particularly Klebsiella and Enterobacter). These lysins showed rapid killing kinetics and were active in the presence of high concentrations of salt and urea and in pH conditions ranging from 5.0 to 10.0. Activity was not inhibited in the presence of the pulmonary surfactant Survanta. While neither enzyme was active in 100% human serum, PlyPa91 retained activity in low serum concentrations. The lysins were effective in the treatment of a P. aeruginosa skin infection in a mouse model, and PlyPa91 protected mice in a lung infection model, making these lysins potential drug candidates for Gram-negative infections of the skin or respiratory mucosa.
Retningslinjer til sundhedsprofessionelle vedr. håndtering af infektion med zikavirus (2019)
Antiviral behandling af hiv smittede personer (2019)
Lumbalpunktur af patienter i blodfortyndende behandling (2019)
Resistance of Influenza Virus to Antiviral Medications
20.09.2019Clinical Infectious Diseases Advance Access
Erratum to: Chlamydia trachomatis and the Risk of Pelvic Inflammatory Disease, Ectopic Pregnancy, and Female Infertility: A Retrospective Cohort Study Among Primary Care Patients
19.09.2019Clinical Infectious Diseases Advance Access
Comparison of repeated doses of ivermectin versus ivermectin plus albendazole for treatment of onchocerciasis – a randomized open-label clinical trial
19.09.2019Clinical Infectious Diseases Advance Access
Association between Toxoplasma gondii infection and thyroid dysfunction: a case-control seroprevalence study
18.09.2019Latest Results for BMC Infectious Diseases
Antimicrobial Stewardship in a Hematological Malignancy Unit: Carbapenem Reduction and Decreased Vancomycin-resistant Enterococcus Infection
18.09.2019Clinical Infectious Diseases Advance Access
Hvad synes Professor Thomas Benfield om"Oral versus Intravenous Antibiotics for Bone and Joint Infection."?
Hvad mener Professor Niels Obel om artiklen"Early, Goal-Directed Therapy for Septic Shock - A Patient-Level Meta-Analysis."?
Hvad synes Professor Thomas Benfield om"Duration of Antibiotic Treatment in Community-Acquired Pneumonia: A Multicenter Randomized Clinical Trial."?
Hvad synes Professor Morten Sodemann om"Evidence-based clinical guidelines for immigrants and refugees."?
Hvad mener Professor Niels Obel om artiklen"Use of statins and risk of AIDS-defining and non-AIDS-defining malignancies among HIV-1 infected patients on antiretroviral therapy."?
Tilmeld dig vores nyhedsbrev og hold dig opdateret om nyt på hjemmesiden
© 2019 Dansk Selskab for Infektionsmedicin
version: 2.5.2 ● design: C P Fischer
Side indlæst på 0,211 s