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Nathalie Courtois, Yvan Caspar, Max Maurin
Pseudomonas aeruginosa is responsible for chronic respiratory tract colonisation and acute exacerbations in cystic fibrosis (CF) patients. This Gram-negative bacterium often develops multidrug resistance, which represents a therapeutic challenge. Our objective was to characterize the phenotypic and genetic β-lactam resistance traits of P. aeruginosa strains isolated from CF patients followed at Grenoble Alpes university hospital. The susceptibility to β-lactam compounds of 123 P. aeruginosa strains collected from the lower respiratory tract of 45 CF patients, between 2010 and 2014, was evaluated...
May 15, 2018: International Journal of Antimicrobial Agents
Kara B Marley, Larry A Kuehn, John W Keele, Benjamin W Wileman, Michael G Gonda
Individuals often respond differently to the same vaccine; some of this variation may be caused by genetic differences among animals. Our objective was to estimate heritability and identify genomic regions associated with humoral response to an Escherichia coli O157:H7 vaccine in beef cattle. Crossbred beef cattle (n = 651) were vaccinated with a commercially available E. coli O157:H7 vaccine. Serum was collected at time of initial vaccination (d 0), booster (d 21), and d 56 after initial vaccination. Total antibodies specific to siderophore receptor and porin proteins in the vaccine were quantified by enzyme-linked immunosorbent assay...
2018: PloS One
Florian Graef, Robert Richter, Verena Fetz, Xabier Murgia, Chiara De Rossi, Nicole Schneider-Daum, Giuseppe Allegretta, Walid A M Elgaher, Jörg Haupenthal, Martin Empting, Felix Beckmann, Mark Brönstrup, Rolf W Hartmann, Sarah Gordon, Claus-Michael Lehr
The cell envelope of Gram-negative bacteria is a formidable biological barrier, inhibiting the action of antibiotics by impeding their permeation into the intracellular environment. In-depth understanding of permeation through this barrier remains a challenge, despite its critical role in antibiotic activity. We therefore designed a divisible in vitro permeation model of the Gram-negative bacterial cell envelope, mimicking its three essential structural elements - the inner membrane, the periplasmic space as well as the outer membrane - on a Transwell® setup...
May 11, 2018: ACS Infectious Diseases
Narges Abdali, Farhan Younas, Samaneh Mafakheri, Karunakar R Pothula, Ulrich Kleinekathöfer, Andreas Tauch, Roland Benz
BACKGROUND: Corynebacterium urealyticum, a pathogenic, multidrug resistant member of the mycolata, is known as causative agent of urinary tract infections although it is a bacterium of the skin flora. This pathogenic bacterium shares with the mycolata the property of having an unusual cell envelope composition and architecture, typical for the genus Corynebacterium. The cell wall of members of the mycolata contains channel-forming proteins for the uptake of solutes. RESULTS: In this study, we provide novel information on the identification and characterization of a pore-forming protein in the cell wall of C...
May 9, 2018: BMC Biochemistry
Chaitra Shankar, Manish Kumar, Ashtawarthani Baskaran, Miracle Magdelene Paul, Nithya Ponmudi, Sridhar Santhanam, Joy Sarojini Michael, Balaji Veeraraghavan
Purpose: Sepsis is a significant cause of morbidity and mortality amongst neonates. Klebsiella pneumoniae is a common cause of nosocomial outbreaks causing bacteraemia and having potential of acquiring plasmids enhancing antimicrobial resistance. In the present study, we investigate K. pneumoniae outbreak causing bacteraemia amongst neonates over a span of 2 months. Isolates were characterised for antimicrobial resistance, virulence, molecular typing for clonality and plasmid typing for transmission dynamics, and patient outcome was investigated...
January 2018: Indian Journal of Medical Microbiology
Anastasia I Lev, Eugeny I Astashkin, Angelina A Kislichkina, Ekaterina V Solovieva, Tatiana I Kombarova, Olga V Korobova, Olga N Ershova, Irina A Alexandrova, Vladimir E Malikov, Alexander G Bogun, Alexander I Borzilov, Nikolay V Volozhantsev, Edward A Svetoch, Nadezhda K Fursova
The antibacterial resistance and virulence genotypes and phenotypes of 148 non-duplicate Klebsiella pneumoniae strains collected from 112 patients in Moscow hospitals in 2012-2016 including isolates from the respiratory system (57%), urine (30%), wounds (5%), cerebrospinal fluid (4%), blood (3%), and rectal swab (1%) were determined. The majority (98%) were multidrug resistant (MDR) strains carrying blaSHV (91%), blaCTX-M (74%), blaTEM (51%), blaOXA (38%), and blaNDM (1%) beta-lactamase genes, class 1 integrons (38%), and the porin protein gene ompK36 (96%)...
April 30, 2018: Pathogens and Global Health
N G Vasconcelos, J Croda, S Simionatto
BACKGROUND: In the current healthcare environment, an alarming rise in multi-drug resistant bacterial infections has led to a global health threat. The lack of new antibiotics has created a need for developing alternative strategies. OBJECTIVE: Understanding the antibacterial mechanisms of Cinnamon and its constituents is crucial to enhance it as a potential new source of antibiotic. The objective of this review is to provide a compilation of all described mechanisms of antibacterial action of Cinnamon and its constituents and synergism with commercial antibiotics in order to better understand how Cinnamon and its constituents can collaborate as alternative treatment to multi-drug resistant bacterial infections...
April 24, 2018: Microbial Pathogenesis
Ishan Ghai, Shashank Ghai
Collective antibiotic drug resistance is a global threat, especially with respect to Gram-negative bacteria. The low permeability of the bacterial outer cell wall has been identified as a challenging barrier that prevents a sufficient antibiotic effect to be attained at low doses of the antibiotic. The Gram-negative bacterial cell envelope comprises an outer membrane that delimits the periplasm from the exterior milieu. The crucial mechanisms of antibiotic entry via outer membrane includes general diffusion porins (Omps) responsible for hydrophilic antibiotics and lipid-mediated pathway for hydrophobic antibiotics...
2018: Infection and Drug Resistance
Varsha Gupta, Ritu Garg, Karthikeyan Kumaraswamy, Priya Datta, Gursimran Kaur Mohi, Jagdish Chander
BACKGROUND: Emergence of carbapenem resistance among Enterobacteriaceae in different geographical regions is of great concern as these bacteria are easily transmissible among patients. Carbapenem-resistance in Enterobacteriaceae is due to production of carbapenemases of various classes and hyper production of the ESBLs (Extended spectrum beta lactamases) and Amp C beta lactamases with reduced cell wall permeability mechanisms. Phenotypic detection and differentiation is important for proper infection control and appropriate patient management...
April 2018: Journal of Laboratory Physicians
Vanessa Checchetto, Ildiko Szabo
Ion channels mediate ion flux across biological membranes and regulate important organellar and cellular tasks. A recent study revealed the presence of four new proteins, the MIM complex (composed by Mim1 and Mim2), Ayr1, OMC7, and OMC8, that are able to form ion-conducting channels in the outer mitochondria membrane (OMM). These findings strongly indicate that the OMM is endowed with many solute-specific channels, in addition to porins and known channels mediating protein import into mitochondria. These solute-specific channels provide essential pathways for the controlled transport of ions and metabolites and may thus add a further layer of specificity to the regulation of mitochondrial function at the organelle-cytosol and/or inter-organellar interface...
April 23, 2018: BioEssays: News and Reviews in Molecular, Cellular and Developmental Biology
Noah Stern, Jacqueline Mejia, Shaomei He, Yu Yang, Matthew Ginder-Vogel, Eric E Roden
Dissimilatory iron-reducing bacteria (DIRB) are known to use humic substances (HS) as electron shuttles for dissimilatory iron reduction (DIR) by transferring electrons to HS-quinone moieties, which in turn rapidly reduce Fe(III) oxides. It has also been proposed that certain components of HS can be mineralized by microorganisms. However, the potential for HS to serve a source of organic carbon (OC) that fuels DIR is unknown. We studied whether isolated humic acids (HA) and humins (HM) could serve as both electron shuttles and electron donors for DIR by freshwater sediment microorganisms...
April 16, 2018: Environmental Science & Technology
Sheila Adams-Sapper, Adam Gayoso, Lee W Riley
Carbapenem-resistant Enterobacteriaceae (CRE) organisms have emerged to become a major global public health threat among antimicrobial resistant bacterial human pathogens. Little is known about how CREs emerge. One characteristic phenotype of CREs is heteroresistance, which is clinically associated with treatment failure in patients given a carbapenem. Through in vitro whole-transcriptome analysis we tracked gene expression over time in two different strains (BR7, BR21) of heteroresistant KPC-producing Klebsiella pneumoniae, first exposed to a bactericidal concentration of imipenem followed by growth in drug-free medium...
2018: Journal of Pathogens
Eduardo J Boeri, María M Wanke, María J Madariaga, María L Teijeiro, Sebastian A Elena, Marcos D Trangoni
Aim: This study aimed to compare the sensitivity (S), specificity (Sp), and positive likelihood ratios (LR+) of four polymerase chain reaction (PCR) assays for the detection of Brucella spp. in dog's clinical samples. Materials and Methods: A total of 595 samples of whole blood, urine, and genital fluids were evaluated between October 2014 and November 2016. To compare PCR assays, the gold standard was defined using a combination of different serological and microbiological test...
February 2018: Veterinary World
Monisha Pathania, Silvia Acosta-Gutierrez, Satya Pratyusha Bhamidimarri, Arnaud Baslé, Mathias Winterhalter, Matteo Ceccarelli, Bert van den Berg
The outer membranes (OM) of many Gram-negative bacteria contain general porins, which form nonspecific, large-diameter channels for the diffusional uptake of small molecules required for cell growth and function. While the porins of Enterobacteriaceae (e.g., E. coli OmpF and OmpC) have been extensively characterized structurally and biochemically, much less is known about their counterparts in Vibrionaceae. Vibrio cholerae, the causative agent of cholera, has two major porins, OmpU and OmpT, for which no structural information is available despite their importance for the bacterium...
April 3, 2018: Structure
Soumya Paul, Bhavani V Peddayelachagiri, Sowmya Nagaraj, Joseph J Kingston, Harsh V Batra
Development of a safe and efficacious vaccine for brucellosis is a long standing challenge for scientists. Recognizing potential antigens towards developing vaccine candidate is crucial. Omp25c, a porin protein of Brucella, is a paralog of two previously identified promising vaccine candidates namely, Omp25 and Omp31, with notable sequence identity. Also, Omp25c is conserved in all major Brucella species. This highlights the possibility of employing this protein in multivalent subunit vaccine based approach of Brucella management...
April 9, 2018: Molecular Immunology
Michał Rurek, Magdalena Czołpińska, Tomasz Andrzej Pawłowski, Aleksandra Maria Staszak, Witold Nowak, Włodzimierz Krzesiński, Tomasz Spiżewski
Mitochondrial responses under drought within Brassica genus are poorly understood. The main goal of this study was to investigate mitochondrial biogenesis of three cauliflower ( Brassica oleracea var. botrytis ) cultivars with varying drought tolerance. Diverse quantitative changes (decreases in abundance mostly) in the mitochondrial proteome were assessed by two-dimensional gel electrophoresis (2D PAGE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Respiratory (e.g., complex II, IV (CII, CIV) and ATP synthase subunits), transporter (including diverse porin isoforms) and matrix multifunctional proteins (e...
April 10, 2018: International Journal of Molecular Sciences
Javier Fernández, Beatriz Guerra, M Rosario Rodicio
Non-typhoidal serovars of Salmonella enterica (NTS) are a leading cause of food-borne disease in animals and humans worldwide. Like other zoonotic bacteria, NTS have the potential to act as reservoirs and vehicles for the transmission of antimicrobial drug resistance in different settings. Of particular concern is the resistance to critical "last resort" antimicrobials, such as carbapenems. In contrast to other Enterobacteriaceae (e.g., Klebsiella pneumoniae , Escherichia coli , and Enterobacter , which are major nosocomial pathogens affecting debilitated and immunocompromised patients), carbapenem resistance is still very rare in NTS...
April 8, 2018: Veterinary Sciences
Zaineb Hamzaoui, Alain Ocampo-Sosa, Marta Fernandez Martinez, Sarrah Landolsi, Sana Ferjani, Elaa Maamar, Mabrouka Saidani, Amine Slim, Luis Martinez-Martinez, Ilhem Boutiba-Ben Boubaker
In K. pneumoniae, the loss of the two major outer membrane porins (OMPs) OmpK35 and OmpK36 confers resistance to carbapenem in strains producing extended spectrum β-lactamases or plasmid-mediated AmpC-type β-lactamases. At Charles Nicolle hospital of Tunis, all carbapenem-resistant Enterobacteriaceae (CRE) were collected over a 6-year period. The aim of this work was to investigate the mechanisms responsible for carbapenem resistance in non-carbapenemase-producing K. pneumoniae (NCPK) strains. Among the 334 CRE collected strains between 2010 and 2015, 44 (13...
April 2, 2018: International Journal of Antimicrobial Agents
Ashlin H Turner, David J Craik, Quentin Kaas, Christina I Schroeder
A diverse range of predatory marine gastropods produce toxins, yet most of these molecules remain uncharacterized. Conus species have received the most attention from researchers, leading to several conopeptides reaching clinical trials. This review aims to summarize what is known about bioactive compounds isolated from species of neglected marine gastropods, especially in the Turridae, Terebridae, Babyloniidae, Muricidae, Buccinidae, Colubrariidae, Nassariidae, Cassidae, and Ranellidae families. Multiple species have been reported to contain bioactive compounds with potential toxic activity, but most of these compounds have not been characterized or even clearly identified...
April 5, 2018: Marine Drugs
Danilo Donnarumma, Claudio Maestri, Pietro Ivan Giammarinaro, Luigi Capriotti, Erika Bartolini, Daniele Veggi, Roberto Petracca, Maria Scarselli, Nathalie Norais
Hydrogen Deuterium exchange (HDx) associated with Mass Spectrometry (MS) is emerging as a powerful tool to provide conformational information on membrane proteins. Unfortunately, as for X-ray diffraction and NMR, HDx performed on reconstituted in vitro systems might not always reflect the in vivo environment. Outer Membrane Vesicles naturally released by E. coli were used to carry out analysis of native OmpF through HDx-MS. A new protocol compatible with HDx analysis and avoiding hindrance from the lipid contents was set-up...
April 5, 2018: Journal of Proteome Research
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