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https://www.readbyqxmd.com/read/28731269/biofilm-formation-and-antibiotic-resistance-in-klebsiella-pneumoniae-urinary-strains
#1
Claudia Vuotto, Francesca Longo, Chiara Pascolini, Gianfranco Donelli, Maria Pia Balice, Maria Francesca Libori, Valentina Tiracchia, Antonino Salvia, Pietro Emanuele Varaldo
AIMS: Multi-drug resistant Klebsiella pneumoniae has become a relevant healthcare-associated pathogen. Capsule, type 1 and 3 fimbriae (mrkA gene), type 2 quorum-sensing system (luxS), synthesis of D-galactan I (wbbM), LPS transport (wzm) and poly-beta-1,6-N-acetyl-D-glucosamine (pgaA) seem involved in K. pneumoniae biofilm. Non-enzymatic antibiotic resistance is related to non-expression or mutation of porins (OmpK35 and OmpK36), and efflux pump (acrB) over-expression. The aim of this study was to analyse some virulence factors of K...
July 21, 2017: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28729124/trends-in-antimicrobial-resistance-in-neisseria-gonorrhoeae-and-molecular-characteristics-of-neisseria-gonorrhoeae-with-decreased-susceptibility-to-ceftriaxone-in-shandong-china-2007-to-2014
#2
Lihong Zhao, Aihua Liu, Ruiying Li, Shuping Zhao
In this study, the trends of AMR in N. gonorrhoeae were analyzed in Shandong Province of China during 2007-2014. Moreover, the ceftriaxone genetic resistance determinants including penA, mtrR, penB, ponA, and pilQ genes were sequenced, and the molecular mechanisms of decreased susceptibility or resistance to ceftriaxone in N. gonorrhoeae were elucidated. Overall, the increasing trends of resistance to PEN, TET, and CIP, and decreasing trends of susceptibility to CRO and AZM were observed in Shandong Province of China between 2007 and 2014...
July 17, 2017: International Journal of Antimicrobial Agents
https://www.readbyqxmd.com/read/28726924/peculiarities-of-thermal-denaturation-of-ompf-porin-from-yersinia-ruckeri
#3
Olga D Novikova, Dmitry K Chistyulin, Valentina A Khomenko, Evgeny V Sidorin, Natalya Yu Kim, Nina M Sanina, Olga Yu Portnyagina, Tamara F Solov'eva, Vladimir N Uversky, Valery L Shnyrov
Irreversible denaturation of membrane proteins in detergent solutions is similar to unfolding of water-soluble multidomain proteins and represents a complex, multistage process. Pore-forming proteins of Gram-negative bacteria are heat-modifiable proteins, i.e., proteins altering their molecular forms (trimers or monomers), and accordingly, their electrophoretic mobilities depending upon denaturation conditions. There are still some contradictory data on the peculiarities of the conformational changes in the porin structure with temperature...
July 20, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28723607/production-of-recombinant-porin-from-y-pseudotuberculosis-in-a-water-soluble-form-for-pseudotuberculosis-diagnostics
#4
Vasily A Golotin, Olga Y Portnyagina, Natalia S Chopenko, Natalia Y Kim, Valery A Rasskazov, Olga D Novikova
OmpF porin from the outer membrane of Yersinia pseudotuberculosis was cloned into pET-40b(+) plasmid. Using E. coli Rosetta (DE3) strain, MX-medium, IPTG concentration of 0.2 mM and post-induction cultivation at 14 °C overnight allowed us to obtain a water-soluble form of the recombinant protein (rs-OmpF). Rs-OmpF was shown to have the ordered spatial structure at the levels of secondary and tertiary structure. Rs-OmpF was found to be effective as diagnostic antigen in ELISA for pseudotuberculosis diagnostics...
July 26, 2017: Biological Chemistry
https://www.readbyqxmd.com/read/28717993/probing-the-binding-affinities-of-imipenem-and-ertapenem-for-outer-membrane-carboxylate-channel-d1-occd1-from-p-aeruginosa-simulation-studies
#5
Kamolrat Somboon, Jitti Niramitranon, Prapasiri Pongprayoon
Pseudomonas aeruginosa is an important nosocomial human pathogen. The major difficulty in the fight against this pathogen is the relative impermeability of its outer membrane (OM). Only specific substrates can penetrate through the OM of P. aeruginosa via substrate-specific porins, so this has become one of the most problematic drug-resistant pathogens. Carbapenems are the most effective drugs for treating P. aeruginosa infections. One such carbapenem that is applied in cases of P. aeruginosa infection is imipenem (IMI), which uses outer membrane carboxylate channel D1 (OccD1) as a point of entry into the pathogen...
August 2017: Journal of Molecular Modeling
https://www.readbyqxmd.com/read/28713357/extensively-drug-resistant-klebsiella-pneumoniae-causing-nosocomial-bloodstream-infections-in-china-molecular-investigation-of-antibiotic-resistance-determinants-informing-therapy-and-clinical-outcomes
#6
Wenzi Bi, Haiyang Liu, Rhys A Dunstan, Bin Li, Von Vergel L Torres, Jianming Cao, Lijiang Chen, Jonathan J Wilksch, Richard A Strugnell, Trevor Lithgow, Tieli Zhou
The rise in diversity of antimicrobial resistance phenotypes seen in Klebsiella pneumoniae is becoming a serious antibiotic management problem. We sought to investigate the molecular characteristics and clinical implications of extensively drug-resistant (XDR) K. pneumoniae isolated from different nosocomial bloodstream infections (BSIs) patients from July 2013 to November 2015. Even in combination treatment, meropenem did not protect against mortality of BSIs patients (P = 0.015). In contrast, tigecycline in combination with other antimicrobial agents significantly protected against mortality (P = 0...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28713335/a-novel-regulatory-cascade-involving-blur-ycgz-and-lon-controls-the-expression-of-escherichia-coli-ompf-porin
#7
Valérie Duval, Kimberly Foster, Jennifer Brewster, Stuart B Levy
In Escherichia coli, OmpF is an important outer membrane protein, which serves as a passive diffusion pore for small compounds including nutrients, antibiotics, and toxic compounds. OmpF expression responds to environmental changes such as temperature, osmolarity, nutrients availability, and toxic compounds via complex regulatory pathways involving transcriptional and post-transcriptional regulation. Our study identified a new regulatory cascade that controls the expression of OmpF porin. This pathway involves BluR, a transcriptional regulator repressing the expression of the ycgZ-ymgABC operon...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28708335/heterogeneity-in-non-epitope-loop-sequence-and-outer-membrane-protein-complexes-alters-antibody-binding-to-the-major-porin-protein-porb-in-serogroup-b-neisseria-meningitidis
#8
Kathryn A Matthias, Michael Brad Strader, Hesham F Nawar, Yamei S Gao, Joonseong Lee, Dhilon S Patel, Wonpil Im, Margaret C Bash
PorB is a well-characterized outer membrane protein that is common among Neisseria species and is required for survival. A vaccine candidate, PorB induces antibody responses that are directed against six variable surface-exposed loops that differ in sequence depending on serotype. Although N. meningitidis is naturally competent and porB genetic mosaicism provides evidence for strong positive selection, the sequences of PorB serotypes commonly associated with invasive disease are often conserved, calling into question the interaction of specific PorB loop sequences in immune engagement...
July 14, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28696278/outer-membrane-permeability-of-cyanobacterium-synechocystis-sp-pcc-6803-studies-of-passive-diffusion-of-small-organic-nutrients-reveal-the-absence-of-classical-porins-and-intrinsically-low-permeability
#9
Hikaru Kowata, Saeko Tochigi, Hideyuki Takahashi, Seiji Kojima
The outer membrane of heterotrophic Gram-negative bacteria plays a role of selective permeability barrier that prevents the influx of toxic compounds, while allowing the non-specific passage of small, hydrophilic nutrients through porin channels. Compared with the heterotrophic Gram-negative bacteria, the outer membrane properties of cyanobacteria, the Gram-negative photoautotrophs, are not clearly understood. In this study, using small carbohydrates, amino acids, and inorganic ions as permeation probes, we determined the outer membrane permeability of Synechocystis sp...
July 10, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28693438/evaluation-of-recombinant-porin-romp2a-protein-as-a-potential-antigen-candidate-for-serodiagnosis-of-human-brucellosis
#10
Prachi Pathak, Ashu Kumar, Duraipandian Thavaselvam
BACKGROUND: Brucellosis is an important zoonotic disease caused by different Brucella species and human brucellosis is commonly prevalent in different states of India. Among various Brucella species, B. melitensis is most pathogenic to human and included as category B biothreat which can cause infection through aerosol, cut, wounds in skin and contact with infected animals. The diagnosis of human brucellosis is very important for proper treatment and management of disease as there is no vaccine available for human use...
July 11, 2017: BMC Infectious Diseases
https://www.readbyqxmd.com/read/28693313/comparative-proteomic-analysis-of-the-outer-membrane-protein-43-omp43-deficient-bartonella-henselae
#11
Jun-Gu Kang, Hee-Woo Lee, Sungjin Ko, Joon-Seok Chae
Outer membrane proteins (OMPs) of gram-negative bacteria constitute the first line of defense that protects the cells against environmental stresses including chemical, biophysical, and biological attacks. Although 43-kDa outer membrane protein (OMP43) is major porin protein among the Bartonella henselae-derived OMPs, its function remains unknown. In this study, OMP43-deficient mutant B. henselae (Δomp43) was generated to investigate function of OMP43. Interestingly, Δomp43 showed a weaker proliferative ability compared to wild type (WT) of B...
July 10, 2017: Journal of Veterinary Science
https://www.readbyqxmd.com/read/28674067/genome-scale-mutational-analysis-of-geobacter-sulfurreducens-reveals-distinct-molecular-mechanisms-for-respiration-and-sensing-of-poised-electrodes-vs-fe-iii-oxides
#12
Chi Ho Chan, Caleb E Levar, Fernanda Jiménez-Otero, Daniel R Bond
Geobacter sulfurreducens generates electrical current by coupling intracellular oxidation of organic acids to reduction of proteins on the cell surface that are able to interface with electrodes. This ability is attributed to the bacterium's capacity to respire other extracellular electron acceptors that require contact, such as insoluble metal oxides. To directly investigate the genetic basis of electrode-based respiration, we constructed Geobacter sulfurreducens transposon-insertion sequencing (Tn-Seq) libraries for growth with soluble fumarate or an electrode as the electron acceptor...
July 3, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28672723/effects-of-salinity-on-the-performance-microbial-community-and-functional-proteins-in-an-aerobic-granular-sludge-system
#13
Xingang Wang, Tongyi Yang, Bing Lin, Yubin Tang
The response mechanism of aerobic granular sludge (AGS) systems to salt stress in high-salinity wastewater treatment processes has not been fully elucidated in current studies. The aim of this study was to reveal the comprehensive effects of salinity on AGS characteristics using microbial community and metaproteomics analyses. The results showed that the removal efficiency of COD, TN and TP decreased significantly with increasing salinity. Under salt stress, the Na(+) content in AGS decreased, while the K(+) and Ca(2+) contents increased...
June 14, 2017: Chemosphere
https://www.readbyqxmd.com/read/28670642/multilocus-sequence-typing-of-carbapenem-resistant-pseudomonas-aeruginosa-isolates-from-patients-presenting-at-port-elizabeth-hospitals-south-africa
#14
D Annear, J Black, S Govender
BACKGROUND: Pseudomonas aeruginosa is an important nosocomial pathogen that exhibits multiple drug resistance with increasing frequency, especially to carbapenems making patient treatment difficult. Carbapenem-resistance may be caused by porin gene mutations, active drug efflux, and carbapenemase production. This study evaluated the incidence of genes responsible for carbapenemase production in carbapenem-resistant Pseudomonas aeruginosa and assessed the genetic relatedness of the isolates by multi locus sequence typing (MLST)...
2017: African Journal of Infectious Diseases
https://www.readbyqxmd.com/read/28654368/evaluation-of-carbapenem-resistance-mechanisms-and-its-association-with-pseudomonas-aeruginosa-infections-in-the-northwest-of-iran
#15
Mohammad Taghi Akhi, Younes Khalili, Reza Ghotaslou, Saber Yousefi, Hossein Samadi Kafil, Behrooz Naghili, Vajihe Sheikhalizadeh
The aims of this study were to determine carbapenem resistance mechanisms, molecular epidemiological relationship, clinical impact, and patient outcome of carbapenem-resistant Pseudomonas aeruginosa (CRPA) infections. A total of 42 nonduplicated CRPA were recovered from Urmia, Iran. Antimicrobial susceptibility tests were carried out using phenotypic methods. The carbapenem resistance mechanisms such as carbapenemase genes, efflux pump hyperexpression, AmpC overproduction, and OprD gene downregulation were determined by phenotypic and molecular methods...
June 27, 2017: Microbial Drug Resistance: MDR: Mechanisms, Epidemiology, and Disease
https://www.readbyqxmd.com/read/28643488/multidrug-resistance-mechanisms-of-carbapenem-resistant-klebsiella-pneumoniae-strains-isolated-in-chongqing-china
#16
Jinrong Yan, Shuli Pu, Xiaojiong Jia, Xiuyu Xu, Shuangshuang Yang, Jing Shi, Shan Sun, Liping Zhang
BACKGROUND: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is considered a serious global threat. However, little is known regarding the multidrug resistance (MDR) mechanisms of CRKP. This study investigated the phenotypes and MDR mechanisms of CRKP and identified their clonal characteristics. METHODS: PCR and sequencing were utilized to identify antibiotic resistance determinants. Integron gene cassette arrays were determined by restriction fragment length polymorphism (RFLP) analysis...
September 2017: Annals of Laboratory Medicine
https://www.readbyqxmd.com/read/28630202/identifying-spectra-of-activity-and-therapeutic-niches-for-ceftazidime-avibactam-and-imipenem-relebactam-against-carbapenem-resistant-enterobacteriaceae
#17
Ghady Haidar, Cornelius J Clancy, Liang Chen, Palash Samanta, Ryan K Shields, Barry N Kreiswirth, M Hong Nguyen
We determined imipenem, imipenem-relebactam, ceftazidime and ceftazidime-avibactam minimum inhibitory concentrations (MICs) against 100 CRE isolates that underwent whole genome sequencing. KPCs were the most common carbapenemases. Forty-six isolates carried ESBLs. With the addition of relebactam, imipenem susceptibility increased from 8% to 88%. With the addition of avibactam, ceftazidime susceptibility increased from 0% to 85%. Neither imipenem-relebactam nor ceftazidime-avibactam was active against MBL-producers...
June 19, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28630162/real-time-dynamics-of-carbon-nanotube-porins-in-supported-lipid-membranes-visualized-by-high-speed-atomic-force-microscopy
#18
Yuliang Zhang, Ramya H Tunuguntla, Pyung-On Choi, Aleksandr Noy
In-plane mobility of proteins in lipid membranes is one of the fundamental mechanisms supporting biological functionality. Here we use high-speed atomic force microscopy (HS-AFM) to show that a novel type of biomimetic channel-carbon nanotube porins (CNTPs)-is also laterally mobile in supported lipid membranes, mimicking biological protein behaviour. HS-AFM can capture real-time dynamics of CNTP motion in the supported lipid bilayer membrane, build long-term trajectories of the CNTP motion and determine the diffusion coefficients associated with this motion...
August 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28591829/benzoate-transport-in-pseudomonas-putida-csv86
#19
Alpa Choudhary, Hemant Purohit, Prashant S Phale
Pseudomonas putida strain CSV86 metabolizes variety of aromatic compounds as the sole carbon source. Genome analysis revealed the presence of genes encoding putative transporters for benzoate, p-hydroxybenzoate, phenylacetate, p-hydroxyphenylacetate and vanillate. Bioinformatic analysis revealed that benzoate transport and metabolism genes are clustered at the ben locus as benK-catA-benE-benF. Protein topology prediction suggests that BenK (aromatic acid-H+ symporter of major facilitator superfamily) has 12 transmembrane α-helices with the conserved motif, LADRXGRKX in loop 2 while BenE (benzoate-H+ symporter protein) has 11 predicted transmembrane α-helices...
June 7, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28576703/porin-flexibility-in-providencia-stuartii-cell-surface-exposed-loops-l5-and-l7-are-markers-of-providencia-porin-omppst1
#20
Que-Tien Tran, Laure Maigre, Tommaso D'Agostino, Matteo Ceccarelli, Mathias Winterhalter, Jean-Marie Pagès, Anne Davin-Regli
Epidemiologically unrelated Providencia stuartii strains isolated in hospitals in the south of France were investigated for their porin sequences and profiles. Noticeable resistance to β-lactams was found to be associated with production of extended spectrum β-lactamases or AmpC overproduction, but not metallo-β-lactamases. At the same time, the expression level of outer membrane porins was unmodified in these isolates. The identity of the amino acid sequences of the major porin OmpPst1 was less than 90% in the tested clinical strains, whereas sequences of the second major porin OmpPst2 were found to be identical in all isolates...
May 30, 2017: Research in Microbiology
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