Prevention, inhibition, and degradation effects of melittin alone and in combination with vancomycin and rifampin against strong biofilm producer strains of methicillin-resistant Staphylococcus epidermidis

Methicillin-resistant Staphylococcus epidermidis (MRSE) bacteria are being recognized as true pathogens as they are able to resist methicillin and commonly form biofilms. Recent studies have shown that antimicrobial peptides (AMPs) are promising agents against biofilm-associated bacterial infections. In this study, we aimed to explore the antibiofilm activity of melittin, either alone or in combination with vancomycin and rifampin, against biofilm-producing MRSE strains. Minimum biofilm preventive concentration (MBPC), minimum biofilm inhibition concentration (MBIC), and minimum biofilm eradication concentration (MBEC), as well as fractional biofilm preventive-, inhibitory-, and eradication concentrations (FBPCi, FBICi, and FBECi), were determined for the antimicrobial agents tested. Cytotoxicity and hemolytic activity of melittin at its synergistic concentration were examined on human embryonic kidney cells (HEK-293) and Red Blood Cells (RBCs), respectively. The effect of melittin on the downregulation of biofilm-associated genes was explored using Real-Time PCR. MBPC, MBIC, and MBEC values for melittin were in the range of 0.625–20, 0.625–20, and 10–40 μg/μL, respectively. Melittin showed high synergy (FBPCi, FBICi and FBECi < 0.5). The synergism resulted in a 64–512-fold, 2–16 and 2–8-fold reduction in melittin, rifampicin and vancomycin concentrations, respectively. The synergistic melittin concentration found to be effective did not manifest either cytotoxicity on HEK-293 or hemolytic activity on RBCs. Results showed that melittin downregulated the expression of biofilm-associated icaA, aap, and psm genes in all isolates tested, ranging from 0.04-folds to 2.11-folds for icaA and from 0.05 to 3.76-folds for aap and psm. The preventive and therapeutic indexes of melittin were improved 8-fold when combined with vancomycin and rifampin. Based on these findings, the combination of melittin with conventional antibiotics could be proposed for treating or preventing biofilm-associated MRSE infections

Targeted Reinforcement of Macrophage Reprogramming Toward M2 Polarization by IL-4-Loaded Hyaluronic Acid Particles

Alteration of macrophage polarization from inflammatory (M1) to anti-inflammatory (M2) phenotype can have striking implications for the regeneration of injured tissues, treatment of inflammatory diseases, and relief of autoimmune disorders. Although certain cytokines like interleukin (IL)-4 and IL-13 are capable of inducing M2 macrophage polarization, their therapeutic potential in vivo is suffering from low efficacy due to their instability and poor access to target cells. Here, we report the synthesis of IL-4-loaded hyaluronic acid (HA) particle for the targeted delivery of cytokines through the high affinity of HA to CD44 receptors of macrophages. HA carriers composed of low, middle, and high molecular weight (MW) polymers were synthesized using divinyl sulfone (DVS) cross-linking. The MW of HA had a negligible effect on the physicochemical properties and biocompatibility of the macrophages, but as an indicative of M2 polarization, a significant change in the arginase-1 (Arg-1) activity, TNF-a release, and IL-10 secretion was observed for the HA particles prepared with high MW polymers. Therefore, these particles were loaded with IL-4 for simultaneous macrophage targeting and M1 to M2 reprogramming, evidenced by a remarkable increase in the Arg-1 to iNOS ratio, as well as CD163 and CD206 upregulation in the M1 macrophages, which were initially triggered by lipopolysaccharide and interferon-y.M.-A.S. acknowledges financial support from Academy of Finland (Decision no. 317316), Iran’s National Elites Foundation and Iran Nanotechnology Initiative Council. T.B.-R. acknowledges financial support from the Fundação para a Ciência e a Tecnologia (Grant no. SFRH/BD/110859/2015). Financial support from the FEDER - Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through the FCT - Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274) is acknowledged. H.A.S. acknowledges financial support from the Sigrid Jusélius Foundation (Decision no. 4704580), the Helsinki Institute of Life Science, and the Academy of Finland (Decision no. 1317042)

Virulence factors and antimicrobial resistance in uropathogenic escherichia coli strains isolated from cystitis and pyelonephritis

Background/aim: The aim of this study was to investigate the prevalence of virulence genes as well as patterns of antibiotic resistance in cystitis and pyelonephritis uropathogenic Escherichia coli (UPEC) isolates. Materials and methods: Two hundred UPEC isolates were collected from hospitalized patients with pyelonephritis (n = 50) and cystitis (n = 150) in Shafa Hospital in Iran. Antimicrobial susceptibility and ESBL production were determined with confirmatory tests. Polymerase chain reaction assay was performed to determine the prevalence of virulence genes in UPEC strains. Results: Of a total 200 UPEC isolates, the highest and lowest resistance rates to antibiotics were for cephalexin (74) and nitrofurantoin (9), respectively. Of these isolates, 72 (36) and 128 (64) strains were ESBL-positive and ESBL-negative, respectively. The frequency of fimH, papC, and hly was 64, 38, and 12, respectively. The most commonly identified virulence gene in ESBL-positive and ESBL-negative strains was fimH 46 (23) and 86 (43), respectively. The hlyA gene was more prevalent among patients with pyelonephritis than cystitis. Conclusion: The frequency of virulence genes was not significantly different between pyelonephritis and cystitis UPEC strains in the studied patients, but the prevalence rates of hlyA and papC genes were higher among UPEC strains isolated from inpatients compared to outpatients; hence, they could be considered as useful targets for prophylactic interventions. © TUBİTAK

Prevalence and antimicrobial susceptibility pattern of toxigenic clostridium difficistrains isolated in iran

Background/aim: Clostridium difficile is a frequent cause of nosocomial infections and has become a major public health concern in developed nations. In the present study, the prevalence and antimicrobial susceptibility pattern of toxigenic C. difficile strains isolated in Iran were investigated. Materials and methods: Between June 2016 and May 2017, 2947 inpatient fecal samples were taken from symptomatic adult hospitalized patients in different units of 32 care facilities in Tehran, Iran. C. difficile strains were identified by microbiological/biochemical methods. Susceptibility to 20 antimicrobials was measured by E-test method. Toxin-specific immunoassays and cytotoxicity assays were used to determine in vitro toxin production. Results: Out of 2947 fecal samples, 538 (18.25) C. difficile isolates were obtained among those with suspected CDI. In E-test method, all C. difficile isolates were susceptible to fidaxomicin, vancomycin, amoxicillin/clavulanate, and meropenem and were resistant to penicillin G. The prevalence of multidrug resistant C. difficile was 69.33 (373/538). Among 538 C. difficile, 147 (27.32), 169 (31.41), and 222 (41.26) isolates were TcdA+/TcdB+, TcdA-/TcdB+, and TcdA-/TcdB-, respectively. Conclusion: The results evidently support the hypothesis of a probable role of toxigenic strains of C. difficile in developing gastrointestinal complaints in patients with diarrhea. © TUBİTAK

The role of multiple marks in epigenetic silencing and the emergence of a stable bivalent chromatin state

We introduce and analyze a minimal model of epigenetic silencing in budding yeast, built upon known biomolecular interactions in the system. Doing so, we identify the epigenetic marks essential for the bistability of epigenetic states. The model explicitly incorporates two key chromatin marks, namely H4K16 acetylation and H3K79 methylation, and explores whether the presence of multiple marks lead to a qualitatively different systems behavior. We find that having both modifications is important for the robustness of epigenetic silencing. Besides the silenced and transcriptionally active fate of chromatin, our model leads to a novel state with bivalent (i.e., both active and silencing) marks under certain perturbations (knock-out mutations, inhibition or enhancement of enzymatic activity). The bivalent state appears under several perturbations and is shown to result in patchy silencing. We also show that the titration effect, owing to a limited supply of silencing proteins, can result in counter-intuitive responses. The design principles of the silencing system is systematically investigated and disparate experimental observations are assessed within a single theoretical framework. Specifically, we discuss the behavior of Sir protein recruitment, spreading and stability of silenced regions in commonly-studied mutants (e.g., sas2, dot1) illuminating the controversial role of Dot1 in the systems biology of yeast silencing.Comment: Supplementary Material, 14 page

Megathrust and accretionary wedge properties and behaviour in the Makran subduction zone

We study the Makran subduction zone, along the southern coasts of Iran and Pakistan, to gain insights into the kinematics and dynamics of accretionary prism deformation. By combining techniques from seismology, geodesy and geomorphology, we are able to put constraints on the shape of the subduction interface and the style of strain across the prism. We also address the long-standing tectonic problem of how the right-lateral shear taken up by strike-slip faulting in the Sistan Suture Zone in eastern Iran is accommodated at the zone’s southern end. We find that the subduction interface in the western Makran may be locked, accumulating elastic strain, and move in megathrust earthquakes. Such earthquakes, and associated tsunamis, present a significant hazard to populations around the Arabian Sea. The time-dependent strain within the accretionary prism, resulting from the megathrust earthquake cycle, may play an important role in the deformation of the Makran region. By considering the kinematics of the 2013 Balochistan and Minab earthquakes, we infer that the local gravitational and far-field compressive forces in the Makran accretionary prism are in balance. This force balance allows us to calculate the mean shear stress and effective coefficient of friction on the Makran megathrust, which we find to be 5–35 MPa and 0.01–0.03, respectively. These values are similar to those found in other subduction zones, showing that the abnormally high sediment thickness in the offshore Makran does not significantly reduce the shear stress on the megathrust.This work forms part of the NERC- and ESRC-funded project ‘Earthquakes without Frontiers’ and was partially supported by the NERC large grant ‘Looking inside the Continents from Space’. CP is funded by an NERC studentship. The facilities of IRIS Data Services, and specifically the IRIS Data Management Center, were used for access to waveforms, related metadata, and/or derived products used in this study. IRIS Data Services are funded through the Seismological Facilities for the Advancement of Geoscience and EarthScope (SAGE) Proposal of the National Science Foundation under Cooperative Agreement EAR-1261681

LPS-responsive beige-like anchor gene mutation associated with possible bronchiolitis obliterans organizing pneumonia associated with hypogammaglobulinemia and normal IgM phenotype and low number of B

LPS-Responsive Beige-like Anchor (LRBA) deficiency is a disease which has recently been described in a group of patients with common variable immunodeficiency (CVID) in association with autoimmunity and/or inflammatory bowel disease (IBD)-like phenotype. We here describe a 10-year-old boy who experienced recurrent infections, mainly in the respiratory system, associated with thrombocytopenia and anemia. Immunological workup showed low numbers of B cells and low IgG, but normal IgM levels. In spite of therapeutic doses of antibiotics, antivirals, and antifungal agents, in addition to immunoglobulin replacement therapy, he developed disseminated involvement of both lungs with peripheral nodules; transbronchial lung biopsy revealed possible bronchiolitis obliterans organizing pneumonia (BOOP). Combined homozygosity mapping and exome sequencing identified a homozygous LRBA mutation in this patient (p.Asp248Glufs * 2). Such clinical and immunological findings have not been described to date and illustrate the broad and variable clinical phenotype of human LRBA deficiency. © 2016 Tehran University of Medical Sciences. All rights reserved

Using Machine Learning Algorithms to Develop a Clinical Decision-Making Tool for COVID-19 Inpatients.

BACKGROUND: Within the UK, COVID-19 has contributed towards over 103,000 deaths. Although multiple risk factors for COVID-19 have been identified, using this data to improve clinical care has proven challenging. The main aim of this study is to develop a reliable, multivariable predictive model for COVID-19 in-patient outcomes, thus enabling risk-stratification and earlier clinical decision-making. METHODS: Anonymised data consisting of 44 independent predictor variables from 355 adults diagnosed with COVID-19, at a UK hospital, was manually extracted from electronic patient records for retrospective, case-control analysis. Primary outcomes included inpatient mortality, required ventilatory support, and duration of inpatient treatment. Pulmonary embolism sequala was the only secondary outcome. After balancing data, key variables were feature selected for each outcome using random forests. Predictive models were then learned and constructed using Bayesian networks. RESULTS: The proposed probabilistic models were able to predict, using feature selected risk factors, the probability of the mentioned outcomes. Overall, our findings demonstrate reliable, multivariable, quantitative predictive models for four outcomes, which utilise readily available clinical information for COVID-19 adult inpatients. Further research is required to externally validate our models and demonstrate their utility as risk stratification and clinical decision-making tools