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Bacterial infection

Rebecca L Lamason, Effie Bastounis, Natasha M Kafai, Ricardo Serrano, Juan C Del Álamo, Julie A Theriot, Matthew D Welch
Spotted fever group (SFG) rickettsiae are human pathogens that infect cells in the vasculature. They disseminate through host tissues by a process of cell-to-cell spread that involves protrusion formation, engulfment, and vacuolar escape. Other bacterial pathogens rely on actin-based motility to provide a physical force for spread. Here, we show that SFG species Rickettsia parkeri typically lack actin tails during spread and instead manipulate host intercellular tension and mechanotransduction to promote spread...
October 20, 2016: Cell
Yohann Nédélec, Joaquín Sanz, Golshid Baharian, Zachary A Szpiech, Alain Pacis, Anne Dumaine, Jean-Christophe Grenier, Andrew Freiman, Aaron J Sams, Steven Hebert, Ariane Pagé Sabourin, Francesca Luca, Ran Blekhman, Ryan D Hernandez, Roger Pique-Regi, Jenny Tung, Vania Yotova, Luis B Barreiro
Individuals from different populations vary considerably in their susceptibility to immune-related diseases. To understand how genetic variation and natural selection contribute to these differences, we tested for the effects of African versus European ancestry on the transcriptional response of primary macrophages to live bacterial pathogens. A total of 9.3% of macrophage-expressed genes show ancestry-associated differences in the gene regulatory response to infection, and African ancestry specifically predicts a stronger inflammatory response and reduced intracellular bacterial growth...
October 20, 2016: Cell
Debarun Dutta, Ajay K Vijay, Naresh Kumar, Mark D P Willcox
Purpose: To determine the ability of antimicrobial peptide melimine-coated contact lenses to reduce the incidence of microbial keratitis (MK) in a rabbit model of contact lens wear. Methods: In vitro antimicrobial activity of melimine-coated contact lenses was determined against Pseudomonas aeruginosa by viable count and a radiolabeled assay. The amount of lipopolysaccharide (LPS) associated with bacteria bound to melimine-coated and control lenses was determined...
October 1, 2016: Investigative Ophthalmology & Visual Science
Jennifer H Madenspacher, Michael B Fessler
Although community-acquired pneumonia remains a major public health problem, murine models of bacterial pneumonia have recently facilitated significant preclinical advances in our understanding of the underlying cellular and molecular pathogenesis. In vivo mouse models capture the integrated physiology and resilience of the host defense response in a manner not revealed by alternative, simplified ex vivo approaches. Several methods have been described in the literature for intrapulmonary inoculation of bacteria in mice, including aerosolization, intranasal delivery, peroral endotracheal cannulation under 'blind' and visualized conditions, and transcutaneous endotracheal cannulation...
September 28, 2016: Journal of Visualized Experiments: JoVE
Mark Shepherd, Maud E S Achard, Adi Idris, Makrina Totsika, Minh-Duy Phan, Kate M Peters, Sohinee Sarkar, Cláudia A Ribeiro, Louise V Holyoake, Dimitrios Ladakis, Glen C Ulett, Matthew J Sweet, Robert K Poole, Alastair G McEwan, Mark A Schembri
Nitric oxide (NO) is a toxic free radical produced by neutrophils and macrophages in response to infection. Uropathogenic Escherichia coli (UPEC) induces a variety of defence mechanisms in response to NO, including direct NO detoxification (Hmp, NorVW, NrfA), iron-sulphur cluster repair (YtfE), and the expression of the NO-tolerant cytochrome bd-I respiratory oxidase (CydAB). The current study quantifies the relative contribution of these systems to UPEC growth and survival during infection. Loss of the flavohemoglobin Hmp and cytochrome bd-I elicit the greatest sensitivity to NO-mediated growth inhibition, whereas all but the periplasmic nitrite reductase NrfA provide protection against neutrophil killing and promote survival within activated macrophages...
October 21, 2016: Scientific Reports
Daniel M Czyż, Neeta Jain-Gupta, Howard A Shuman, Sean Crosson
Brucella abortus is an intracellular bacterial pathogen and an etiological agent of the zoonotic disease known as brucellosis. Brucellosis can be challenging to treat with conventional antibiotic therapies and, in some cases, may develop into a debilitating and life-threatening chronic illness. We used multiple independent assays of in vitro metabolism and intracellular replication to screen a library of 480 known bioactive compounds for novel B. abortus anti-infectives. Eighteen non-cytotoxic compounds specifically inhibited B...
October 21, 2016: Scientific Reports
Jun Hamano, Yasuharu Tokuda
OBJECTIVES: To explore whether the combination of changes in heart rate and body temperature can predict bacterial infection in home care patients. METHODS: This multicenter, prospective cohort study was conducted in Japan from March 2012 through December 2013 and involved three clinics. The study population comprised all patients who received regular home visit services for at least 3 months and met one of the following inclusion criteria: 1) fever over 37.5°C at home visit, 2) physician's clinical suspicion of fever, or 3) physician's suspicion of bacterial infection...
October 21, 2016: Postgraduate Medicine
Corinne Ruppen, Laurent Decosterd, Parham Sendi
BACKGROUND: According to expert opinions, gentamicin should be administered as an adjunct to penicillin against severe group B streptococcal (GBS) infections. Whether the adjunct is important is of particular interest for elderly patients. Not only is the risk of aminoglycoside nephrotoxicity higher in elderly persons, but their immune defence to bacterial infections may also be impaired. METHOD: Time-kill assays with human blood products, such as serum, neutrophilic granulocytes (opsonophagocytic assays) and whole blood from healthy, elderly volunteers were performed to evaluate the effect of gentamicin in combination with penicillin...
October 21, 2016: Infectious Diseases
Matteo Bassetti, Alessia Carnelutti, Maddalena Peghin
The isolation of multi-drug-resistant gram-negative (MDRGN) pathogens has progressively increased worldwide and has been associated with important delays in the prescription of an adequate antibiotic treatment, resulting in increased mortality rates. Patient's stratification for MDRGN infections to optimize the prescription of an adequate empiric antimicrobial regimen is crucial. Areas covered: This article covers MDRGN epidemiology, with a specific focus on risk factors for harbouring infections sustained by extended-spectrum-Beta-lactamase (ESBL), carbapenem resistant Enterobacteriacae (CRE), MDR Pseudomonas aeruginosa and MDR Acinetobacter baumanii...
October 21, 2016: Expert Review of Anti-infective Therapy
Barbara Maciejewska, Bartosz Roszniowski, Akbar Espaillat, Agata Kęsik-Szeloch, Grazyna Majkowska-Skrobek, Andrew M Kropinski, Yves Briers, Felipe Cava, Rob Lavigne, Zuzanna Drulis-Kawa
Lytic bacteriophages and phage-encoded endolysins (peptidoglycan hydrolases) provide a source for the development of novel antimicrobial strategies. In the present study, we focus on the closely related (96 % DNA sequence identity) environmental myoviruses vB_KpnM_KP15 (KP15) and vB_KpnM_KP27 (KP27) infecting multidrug-resistant Klebsiella pneumoniae and Klebsiella oxytoca strains. Their genome organisation and evolutionary relationship are compared to Enterobacter phage phiEap-3 and Klebsiella phages Matisse and Miro...
October 21, 2016: Applied Microbiology and Biotechnology
Michael G Wolfe, Qiang Zhang, Christy Hui, Katherine Radford, Parameswaran Nair, John D Brennan
With over 4.8 million Canadians suffering from chronic airway diseases, respiratory exacerbations are currently the leading cause of hospitalization in Canada. In cases of bacterial infection, neutrophil cell density increases from ∼10 million cells per gram to over 15 million cells per gram. As sputum is a direct discharge from the primarily affected areas of respiratory diseases, quantification of granulocytes (including neutrophils) can be used to effectively determine a course of patient treatment. Unfortunately this quantification is currently limited to labour-intensive and time-consuming cell counts...
October 21, 2016: Analyst
Khosro Adibkia, Golrokh Khorasani, Shahriar Payab, Farzaneh Lotfipour
Purpose: Bacterial pneumonia is a common lung infection caused by different types of bacteria. Azithromycin (AZI), an azalide antibiotic, is widely used to manage pneumococcal infections. Studies have shown that antibiotics in nanocarriers may lead to increased antibacterial activity and reduced toxicity. The aim of this work was to valuate in vitro antibacterial performance azithromycin-Eudragit RS100 nano-formulations against Streptococcus pneumoniae and Staphylococcus aureus. Methods: AZI-Eudragit RS100 nanoparticles were prepared via electrospinning technique and the in vitro antibacterial performance against S...
September 2016: Advanced Pharmaceutical Bulletin
Kazuhiko Umazume, Jun Suzuki, Yoshihiko Usui, Yoshihiro Wakabayashi, Hiroshi Goto
Purpose. Endogenous endophthalmitis (EE) is a rare ocular disease caused by bacterial or fungal infection of intraocular spaces by hematogenous spread of pathogens from distant infectious loci in the body. We investigated the clinical characteristics and management of eyes with EE in ten consecutive patients. Methods. Ten patients (10 eyes) with EE treated at Tokyo Medical University Hospital in 2014 were reviewed. We retrospectively studied the causative organisms, systemic complications, pre/postoperative mean best-corrected visual acuity (BCVA), and status of posterior vitreous detachment (PVD)...
2016: Journal of Ophthalmology
Tobias Wiedemann, Stefan Hofbaur, Eva Loell, Gabriele Rieder
Interleukin-8 (IL-8) is a potent neutrophil-activating chemokine which triggers the infiltration and migration of neutrophils into areas of bacterial infection. Helicobacter pylori-infected patient studies as well as animal models have revealed that H. pylori type I strains carrying an intact cytotoxin-associated gene pathogenicity island (cag-PAI) with a functional type IV secretion system (T4SS) induce IL-8 expression and secretion in gastric mucosa. This gastric mucosal IL-8 expression correlates with severe histological changes due to H...
September 29, 2016: European Journal of Microbiology & Immunology
Karolina Niska, Narcyz Knap, Anna Kędzia, Maciej Jaskiewicz, Wojciech Kamysz, Iwona Inkielewicz-Stepniak
Objectives: In dentistry, silver nanoparticles (AgNPs) have drawn particular attention because of their wide antimicrobial activity spectrum. However, controversial information on AgNPs toxicity limited their use in oral infections. Therefore, the aim of the present study was to evaluate the antibacterial activities against a panel of oral pathogenic bacteria and bacterial biofilms together with potential cytotoxic effects on human gingival fibroblasts of 10 nm AgNPs: non-functionalized - uncapped (AgNPs-UC) as well as surface-functionalized with capping agent: lipoic acid (AgNPs-LA), polyethylene glycol (AgNPs-PEG) or tannic acid (AgNPs-TA) using silver nitrate (AgNO3) as control...
2016: International Journal of Medical Sciences
Yaohong Wang, Sudeep P George, Swati Roy, Eric Pham, Amin Esmaeilniakooshkghazi, Seema Khurana
In the small intestine, epithelial cells are derived from stem cells in the crypts, migrate up the villus as they differentiate and are ultimately shed from the villus tips. This process of proliferation and shedding is tightly regulated to maintain the intestinal architecture and tissue homeostasis. Apoptosis regulates both the number of stem cells in the crypts as well as the sloughing of cells from the villus tips. Previously, we have shown that villin, an epithelial cell-specific actin-binding protein functions as an anti-apoptotic protein in the gastrointestinal epithelium...
October 21, 2016: Scientific Reports
Alexandre Boulos, Katherine Rand, Josh A Johnson, Jacqueline Gautier, Michael Koster
Infections (including sepsis, meningitis, pneumonia and tetanus) stand as a major contributor to neonatal mortality in Haiti (22%). Infants acquire bacteria that cause neonatal sepsis directly from the mother's blood, skin or vaginal tract either before or during delivery. Nosocomial and environmental pathogens introduce further risk after delivery. The absence of cohesive medical systems and methods for collecting information limits the available data in countries such as Haiti. This study seeks to add more information on the burden of severe bacterial infections and their etiology in neonates of Haiti...
October 19, 2016: Journal of Tropical Pediatrics
Jie Chen, Qiang Chen, Xin-Jiang Lu, Jiong Chen
Liver-expressed antimicrobial peptide 2 (LEAP-2) is a cationic peptide that plays an important role in the host's innate immune system. However, the mechanism by which LEAP-2 modulates/regulates the host defense against pathogens remains largely unknown. In this study, we identified a cDNA sequence encoding LEAP-2 homolog (BpLEAP-2) in the mudskipper, Boleophthalmus pectinirostris. Sequence analysis revealed that BpLEAP-2 belonged to the fish LEAP-2A cluster and that it was closely related to ayu LEAP-2. BpLEAP-2 mRNA was detected in a wide range of tissues, with the highest level of transcripts found in the liver...
October 17, 2016: Fish & Shellfish Immunology
Golnaz Salehipour-Shirazi, Laura V Ferguson, Brent J Sinclair
Cold exposure appears to activate aspects of the insect immune system; however, the functional significance of the relationship between cold and immunity is unclear. Insect success at low temperatures is shaped in part by interactions with biotic stressors, such as pathogens, thus it is important to understand how and why immunity might be activated by cold. Here we explore which components of the immune system are activated, and whether those components differ among different kinds of cold exposure. We exposed Drosophila melanogaster to both acute (2h, -2°C) and sustained (10h, -0...
October 17, 2016: Journal of Insect Physiology
Suxu Tan, Jun Yao, Tao Zhou, Shikai Liu, Zihao Yuan, Changxu Tian, Qi Li, Zhanjiang Liu
The Rho family GTPases are a group of small monomeric G proteins, which are molecular switches in signaling pathways. They have been known to regulate a diverse range of cellular processes including actin cytoskeleton rearrangement and microtubule dynamics. In particular, their participations in immune responses are also significant. However, little information of the Rho GTPases is available in teleost including channel catfish, an economically important species and one of the best teleost models for immune research...
October 17, 2016: Developmental and Comparative Immunology
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