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https://www.readbyqxmd.com/read/29053557/bacterial-keratitis-isolated-organisms-and-antibiotic-resistance-patterns-in-san-francisco
#1
Michelle Y Peng, Vicky Cevallos, Stephen D McLeod, Thomas M Lietman, Jennifer Rose-Nussbaumer
PURPOSE: Understanding the spectrum of pathogens in a given geographic region is important when deciding on empiric antibiotic therapy. In this study, we evaluate the spectrum of bacterial organisms cultured from corneal samples and their antibiotic sensitivities to guide initial treatment of keratitis. METHODS: We performed a retrospective case review of cultures from suspected infectious keratitis cases at the Francis I. Proctor Foundation, University of California, San Francisco, from 1996 through 2015...
October 17, 2017: Cornea
https://www.readbyqxmd.com/read/29053280/structural-and-biochemical-investigation-of-pglf-from-campylobacter-jejuni-reveals-a-new-mechanism-for-a-member-of-the-short-chain-dehydrogenase-reductase-superfamily
#2
Alexander S Riegert, James B Thoden, Ian C Schoenhofen, David C Watson, N Martin Young, Peter A Tipton, Hazel M Holden
Within recent years it has become apparent that protein glycosylation is not limited to eukaryotes. Indeed, in Campylobacter jejuni, a Gram negative bacterium, more than 60 of its proteins are known to be glycosylated. One of the sugars found in such glycosylated proteins is 2,4-diacetamido-2,4,6-trideoxy--d-glucopyranose, hereafter referred to as QuiNAc4NAc. The pathway for its biosynthesis, initiating with UDP-GlcNAc, requires three enzymes referred to as PglF, PglE, and PlgD. The focus of this investigation is on PglF, an NAD+-dependent sugar 4,6-dehydratase known to belong to the short chain dehydrogenase/reductase (SDR) superfamily...
October 20, 2017: Biochemistry
https://www.readbyqxmd.com/read/29053278/it-s-complicated-curvature-diffusion-and-lipid-sorting-within-the-two-membranes-of-escherichia-coli
#3
Pin Chia Hsu, Mohd Firdaus Samsudin, Jonathan Shearer, Syma Khalid
The cell envelope of Gram-negative bacteria is composed of two membranes separated by a soluble region. Here, we report microsecond timescale coarse-grained molecular dynamics simulations of models of the E. coli cell envelope that incorporate both membranes and various native membrane proteins. Our results predict that both the inner and outer membranes curve in a manner dependent on the size of the embedded proteins. The tightly cross-linked lipopolysaccharide molecules (LPS) of the outer membrane cause a strong coupling between the movement of proteins and lipids...
October 20, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29052670/novel-bis-cyclic-guanidines-as-potent-membrane-active-antibacterial-agents-with-therapeutic-potential
#4
Peng Teng, Alekhya Nimmagadda, Ma Su, Yuzhu Hong, Ning Shen, Chunpu Li, Ling-Yu Tsai, Jessica Cao, Qi Li, Jianfeng Cai
We designed a class of small dimeric cyclic guanidine derivatives which display potent antibacterial activity against both multidrug-resistant Gram-negative and Gram-positive bacteria. They could compromise bacterial membranes without developing resistance, inhibit biofilms formed by E. coli, and exhibit excellent in vivo activity in the MRSA-infected thigh burden mouse model.
October 20, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/29052356/in-vitro-biocompatibility-bioactivity-and-photoluminescence-properties-of-eu-3-sr-2-dual-doped-nano-hydroxyapatite-for-biomedical-applications
#5
Lakshmanaperumal Sundarabharathi, Hemalatha Parangusan, Deepalekshmi Ponnamma, Mariam Al Ali Al-Maadeed, Mahendran Chinnaswamy
In the present investigation, we have successfully synthesized luminescent Eu(3+) -doped and Eu(3+) /Sr(2+) codoped hydroxyapatite (HA) nanoparticles through sol-gel assisted precipitation method with the aim of developing novel biomaterials containing osteoblast mineral (Sr(2+) ) and luminescence activator (Eu(3+) ). The structure, morphology, thermal stability, and luminescence properties of the resultant spherical nanoparticles (50-100 nm diameters) were studied. Moreover, the in-vitro bioactivity of Eu0...
October 20, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
https://www.readbyqxmd.com/read/29052060/magnetic-poly-n-isopropylacrylamide-nanocomposites-effect-of-preparation-method-on-antibacterial-properties
#6
Nhung H A Nguyen, Mohamed S A Darwish, Ivan Stibor, Pavel Kejzlar, Alena Ševců
The most challenging task in the preparation of magnetic poly(N-isopropylacrylamide) (Fe3O4-PNIPAAm) nanocomposites for bio-applications is to maximise their reactivity and stability. Emulsion polymerisation, in situ precipitation and physical addition were used to produce Fe3O4-PNIPAAm-1, Fe3O4-PNIPAAm-2 and Fe3O4-PNIPAAm-3, respectively. Their properties were characterised using scanning electron microscopy (morphology), zeta-potential (surface charge), thermogravimetric analysis (stability), vibrating sample magnetometry (magnetisation) and dynamic light scattering...
October 19, 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/29051936/nio-nanoflakes-grafted-graphene-an-excellent-photocatalyst-and-a-novel-nanomaterial-for-achieving-complete-pathogen-control
#7
A Arshad, J Iqbal, Q Mansoor
The increased levels of industrial pollutants in water and of drug-resistant pathogens more generally are a serious threat to human and aquatic life. Herein, we present the solar-light-induced dye removal and bactericidal properties of nickel oxide (NiO) and graphene nanoplatelet (GNP) nanocomposites. The conducting nature of GNPs is the key factor that accounts for the enhanced photocatalytic and antibacterial activity. Remarkably, the graphene/NiO nanocomposite shows outstanding photocatalytic activity (99% degradation) as compared to NiO (34%) alone, which makes it a potential candidate for the depollution of dye-contaminated water...
October 20, 2017: Nanoscale
https://www.readbyqxmd.com/read/29051762/specific-pathogen-recognition-by-multiple-innate-immune-sensors-in-an-invertebrate
#8
Guillaume Tetreau, Silvain Pinaud, Anaïs Portet, Richard Galinier, Benjamin Gourbal, David Duval
Detection of pathogens by all living organisms is the primary step needed to implement a coherent and efficient immune response. This implies a mediation by different soluble and/or membrane-anchored proteins related to innate immune receptors called PRRs (pattern-recognition receptors) to trigger immune signaling pathways. In most invertebrates, their roles have been inferred by analogy to those already characterized in vertebrate homologs. Despite the induction of their gene expression upon challenge and the presence of structural domains associated with the detection of pathogen-associated molecular patterns in their sequence, their exact role in the induction of immune response and their binding capacity still remain to be demonstrated...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/29051609/liquid-infused-nitric-oxide-releasing-linorel-silicone-for-decreased-fouling-thrombosis-and-infection-of-medical-devices
#9
Marcus J Goudie, Jitendra Pant, Hitesh Handa
Recent reports on liquid-infused materials have shown promise in creating ultra-low fouling surfaces, but are limited in their ability to prevent bacterial proliferation and prevent platelet activation in blood-contacting applications. In this work, a liquid-infused nitric oxide-releasing (LINORel) material is created by incorporating the nitric oxide (NO) donor S-nitroso-acetylpenicillamine (SNAP) and silicone oil in commercial medical grade silicone rubber tubing through a solvent swelling process. This combination provides several key advantages over previous NO-releasing materials, including decreased leaching of NO donor, controlled release of NO, and maintenance of ultra-low fouling property of liquid-infused materials...
October 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29051092/a-study-on-the-targeted-surveillance-of-nosocomial-infection-in-intensive-care-units-of-177-hospitals-in-jiangsu-province-of-china
#10
Yang Li, Xiao-Li Cao, Hai Ge, Yi-Hong Jiang, Hong Zhou, Wei Zheng
BACKGROUND: Nosocomial infections (NIs) impact care and costs in hospitals across the globe. There are minimal data on targeted surveillance of NI in intensive care units (ICUs), and data specific to the risk factors for NI are especially limited. METHODS: One hundred seventy-seven secondary and tertiary hospitals performed NI targeted surveillance in their ICUs. The data were collected and summarized by Minke software, then fed back once per quarter. RESULTS: The incidence of NI appeared to decrease, and the incidence of NI per 1000 patient-days and adjusted incidence were 25...
October 16, 2017: Journal of Hospital Infection
https://www.readbyqxmd.com/read/29051057/mannheimia-haemolytica-a2-secretes-different-proteases-into-the-culture-medium-and-in-outer-membrane-vesicles
#11
Gerardo Ramírez Rico, Moisés Martínez-Castillo, Cynthia González-Ruíz, Sarahí Luna-Castro, Mireya de la Garza
Respiratory diseases in ruminants have a significantly negative impact on the worldwide economy. The bacterium Mannheimia haemolytica is involved in pneumonic infections in bovine and ovine. In gram-negative bacteria, six secretion systems related to the colonization process and host tissue damage have been reported. In addition, in the last two decades, the production of outer membrane vesicles has been studied as a different bacterial strategy to release virulence factors, such as exotoxins, lipopolysaccharides, and proteases...
October 17, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/29050599/development-of-chitosan-sodium-phytate-nanoparticles-as-a-potent-antibacterial-agent
#12
Jie Yang, Hao Lu, Man Li, Jing Liu, Shuangling Zhang, Liu Xiong, Qingjie Sun
Chitosan nanoparticles have attracted considerable attention as a potential carrier for food and pharmaceutical applications. Herein, using natural sodium phytate as a gelation agent, we developed a new type of green and biocompatible chitosan nanoparticles. We discovered that the chitosan-sodium phytate nanoparticles exhibited potent antibacterial activities. The chitosan-sodium phytate nanoparticles prepared from low molecular weight (LMW, 140±7kDa) and medium molecular weight (MMW, 454±21kDa) chitosan were spherical...
December 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/29050591/benign-development-of-cotton-with-antibacterial-activity-and-metal-sorpability-through-introduction-amino-triazole-moieties-and-agnps-in-cotton-structure-pre-treated-with-periodate
#13
Amina L Mohamed, Ahmed G Hassabo, S Shaarawy, A Hebeish
The research work presented herein was undertaken with a view to develop, characterize and highlight modified cotton fabrics that acquire durable antibacterial activity in concomitant with high metal sorption capacity. The development is based on reacting cotton cellulose previously oxidized by sodium periodate-with 4 amino-1,2,4 triazole in presence and absence of silver nano particles (AgNPs). The idea behind the periodate pretreatment is to convert (via oxidative cleavge) the 2,3-vicinal diol of the anhydroglucose units of cotton into aldehyde groups...
December 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/29050018/root-surface-biofilms-and-caries
#14
Thuy Do, Nailê Damé-Teixeira, Monika Naginyte, Philip D Marsh
Following gingival recession, which increases with age, the root surface becomes exposed, creating new environments for microbial colonization and biofilm formation. The formation of root surface biofilms is influenced by the availability and composition of saliva and gingival crevicular fluid; they provide components for the conditioning film (acquired root surface pellicle) and also act as a source of nutrients. The early bacterial colonizers of the root surface are similar to those found on the enamel, and Gram-positive species such as Streptococcus sanguinis, S...
2017: Monographs in Oral Science
https://www.readbyqxmd.com/read/29049387/quantifying-the-strength-of-quorum-sensing-crosstalk-within-microbial-communities
#15
Kalinga Pavan T Silva, Prithiviraj Chellamuthu, James Q Boedicker
In multispecies microbial communities, the exchange of signals such as acyl-homoserine lactones (AHL) enables communication within and between species of Gram-negative bacteria. This process, commonly known as quorum sensing, aids in the regulation of genes crucial for the survival of species within heterogeneous populations of microbes. Although signal exchange was studied extensively in well-mixed environments, less is known about the consequences of crosstalk in spatially distributed mixtures of species...
October 19, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/29049365/myd88-dependent-inflammasome-activation-and-autophagy-inhibition-contributes-to-ehrlichia-induced-liver-injury-and-toxic-shock
#16
Muhamuda Kader, Mounia El-Azher, Jennie Vorhauer, Bhushan B Kode, Jakob Z Wells, Donna Stolz, George Michalopoulos, Alan Wells, Melanie Scott, Nahed Ismail
Severe hepatic inflammation is a common cause of acute liver injury following systemic infection with Ehrlichia, obligate Gram-negative intracellular bacteria that lack lipopolysaccharide (LPS). We have previously shown that type I IFN (IFN-I) and inflammasome activation are key host-pathogenic mediators that promote excessive inflammation and liver damage following fatal Ehrlichia infection. However, the underlying signals and mechanisms that regulate protective immunity and immunopathology during Ehrlichia infection are not well understood...
October 19, 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/29048164/development-of-a-modular-synthetic-route-to-pleuromutilin-12-epi-mutilins-and-related-structures
#17
Mingshuo Zeng, Stephen K Murphy, Seth B Herzon
We describe the development of an enantioselective synthetic route to (+)-pleuromutilin (1), (+)-12-epi-mutilin, and related derivatives. A key hydrindanone was prepared in three steps and 48% overall yield from cyclohex-2-en-1-one. 1,4-Hydrocyanation provided a nitrile (53%, or 85% based on recovered starting material) that was converted to the eneimide 57 in 80% yield by the 1,2-addition of methyllithium to the nitrile function, cyclization, and in situ acylation with di-tert-butyldicarbonate. The eneimide 57 was employed in a two-fold neopentylic coupling reaction with an organolithium reagent derived from the alkyl iodides (R)- or (S)-30, which contain the C11-C13 atoms of the target, to provide diastereomeric diketones in 60% or 48% yield (for coupling with (R)- or (S)-30, respectively)...
October 19, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29047423/antimicrobial-nonsusceptibility-of-gram-negative-bloodstream-isolates-veterans-health-administration-system-united-states-2003-2013-1
#18
Michihiko Goto, Jennifer S McDanel, Makoto M Jones, Daniel J Livorsi, Michael E Ohl, Brice F Beck, Kelly K Richardson, Bruce Alexander, Eli N Perencevich
Bacteremia caused by gram-negative bacteria is associated with serious illness and death, and emergence of antimicrobial drug resistance in these bacteria is a major concern. Using national microbiology and patient data for 2003-2013 from the US Veterans Health Administration, we characterized nonsusceptibility trends of community-acquired, community-onset; healthcare-associated, community-onset; and hospital-onset bacteremia for selected gram-negative bacteria (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, and Acinetobacter spp...
November 2017: Emerging Infectious Diseases
https://www.readbyqxmd.com/read/29047421/pedobacter-kyonggii-sp-nov-a-psychrotolerant-bacterium-isolated-from-forest-soil
#19
Dhiraj Kumar Chaudhary, Sang Don Lee, Jaisoo Kim
Strain K-4-11-1(T), a psychrotolerant, light salmon-coloured, Gram-stain-negative, non-motile and rod-shaped bacterium, was isolated from forest soil of Kyonggi University, Suwon, South Korea. It was able to grow at 0-32 °C, at pH 5.0-10.0 and with 0-1.5 % (w/v) NaCl. This strain was taxonomically characterized by a polyphasic approach. Based on 16S rRNA gene sequence analysis, strain K-4-11-1(T) belongs to the genus Pedobacter and is closely related to Pedobacter ginsenosidimutans THG-45(T) (98.75 % sequence similarity), Pedobacter borealis G-1(T) (98...
October 19, 2017: International Journal of Systematic and Evolutionary Microbiology
https://www.readbyqxmd.com/read/29046783/phenotypic-and-genotypic-characteristics-of-esbl-and-ampc-producing-organisms-associated-with-bacteraemia-in-ho-chi-minh-city-vietnam
#20
Nguyen Phu Huong Lan, Nguyen Huu Hien, Tu Le Thi Phuong, Duy Pham Thanh, Nga Tran Vu Thieu, Dung Tran Thi Ngoc, Ha Thanh Tuyen, Phat Voong Vinh, Matthew J Ellington, Guy E Thwaites, Nguyen Van Vinh Chau, Stephen Baker, Christine J Boinett
BACKGROUND: Broad-spectrum antimicrobials are commonly used as empirical therapy for infections of presumed bacterial origin. Increasing resistance to these antimicrobial agents has prompted the need for alternative therapies and more effective surveillance. Better surveillance leads to more informed and improved delivery of therapeutic interventions, potentially leading to better treatment outcomes. METHODS: We screened 1017 Gram negative bacteria (excluding Pseudomonas spp...
2017: Antimicrobial Resistance and Infection Control
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