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quorum sensing and resistence gene

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https://www.readbyqxmd.com/read/28106797/the-complex-relationship-between-virulence-and-antibiotic-resistance
#1
REVIEW
Meredith Schroeder, Benjamin D Brooks, Amanda E Brooks
Antibiotic resistance, prompted by the overuse of antimicrobial agents, may arise from a variety of mechanisms, particularly horizontal gene transfer of virulence and antibiotic resistance genes, which is often facilitated by biofilm formation. The importance of phenotypic changes seen in a biofilm, which lead to genotypic alterations, cannot be overstated. Irrespective of if the biofilm is single microbe or polymicrobial, bacteria, protected within a biofilm from the external environment, communicate through signal transduction pathways (e...
January 18, 2017: Genes
https://www.readbyqxmd.com/read/28077586/redeploying-%C3%AE-lactam-antibiotics-as-a-novel-antivirulence-strategy-for-the-treatment-of-methicillin-resistant-staphylococcus-aureus-infections
#2
Elaine M Waters, Justine K Rudkin, Simone Coughlan, Geremy C Clair, Joshua N Adkins, Suzanna Gore, Guoqing Xia, Nikki S Black, Tim Downing, Eoghan O'Neill, Aras Kadioglu, James P O'Gara
Innovative approaches to the use of existing antibiotics is an important strategy in efforts to address the escalating antimicrobial resistance crisis. We report a new approach to the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections by demonstrating that oxacillin can be used to significantly attenuate the virulence of MRSA despite the pathogen being resistant to this drug. Using mechanistic in vitro assays and in vivo models of invasive pneumonia and sepsis, we show that oxacillin-treated MRSA strains are significantly attenuated in virulence...
January 1, 2017: Journal of Infectious Diseases
https://www.readbyqxmd.com/read/28056745/exploiting-quorum-sensing-inhibition-for-the-control-of-pseudomonas-aeruginosa-and-acinetobacter-baumannii-biofilms
#3
Israel Castillo-Juarez, Luis Esaú López-Jácome, Gloria Soberón-Chávez, María Tomás, Jintae Lee, Paulina Castañeda-Tamez, Iván Ángelo Hernández-Bárragan, Martha Yumiko Cruz-Muñiz, Toshinari Maeda, Thomas K Wood, Rodolfo García-Contreras
Pseudomonas aeruginosa and Acinetobacter baumannii are two of the main bacteria responsible for nosocomial infections; both organisms are resistant to several classes of antibiotics making their infections very difficult to treat. Moreover, they possess a remarkable ability to form biofilms, which further enhances their antimicrobial resistance. Both organisms coordinate their formation of biofilms and their expression of virulence factors through quorum sensing, a system that regulates gene expression at high cell densities and that plays a key role in the establishment of bacterial infections...
January 5, 2017: Current Topics in Medicinal Chemistry
https://www.readbyqxmd.com/read/28045495/bacterial-networks-on-hydrophobic-micropillars
#4
Zeinab Jahed, Hamed Shahsavan, Mohit S Verma, Jacob L Rogowski, Brandon B Seo, Boxin Zhao, Ting Y Tsui, Frank X Gu, Mohammad R K Mofrad
Bacteria have evolved as intelligent microorganisms that can colonize and form highly structured and cooperative multicellular communities with sophisticated singular and collective behaviors. The initial stages of colony formation and intercellular communication are particularly important to understand and depend highly on the spatial organization of cells. Controlling the distribution and growth of bacterial cells at the nanoscale is, therefore, of great interest in understanding the mechanisms of cell-cell communication at the initial stages of colony formation...
January 9, 2017: ACS Nano
https://www.readbyqxmd.com/read/28036056/genetic-regulation-of-virulence-and-antibiotic-resistance-in-acinetobacter-baumannii
#5
REVIEW
Carsten Kröger, Stefani C Kary, Kristina Schauer, Andrew D S Cameron
Multidrug resistant microorganisms are forecast to become the single biggest challenge to medical care in the 21st century. Over the last decades, members of the genus Acinetobacter have emerged as bacterial opportunistic pathogens, in particular as challenging nosocomial pathogens because of the rapid evolution of antimicrobial resistances. Although we lack fundamental biological insight into virulence mechanisms, an increasing number of researchers are working to identify virulence factors and to study antibiotic resistance...
December 28, 2016: Genes
https://www.readbyqxmd.com/read/28035988/antibiotic-resistant-superbugs-assessment-of-the-interrelationship-of-occurrence-in-clinical-settings-and-environmental-niches
#6
REVIEW
Anthony Ayodeji Adegoke, Adekunle Christopher Faleye, Gulshan Singh, Thor Axel Stenström
The increasing threat to global health posed by antibiotic resistance remains of serious concern. Human health remains at higher risk due to several reported therapeutic failures to many life threatening drug resistant microbial infections. The resultant effects have been prolonged hospital stay, higher cost of alternative therapy, increased mortality, etc. This opinionated review considers the two main concerns in integrated human health risk assessment (i.e., residual antibiotics and antibiotic resistant genes) in various compartments of human environment, as well as clinical dynamics associated with the development and transfer of antibiotic resistance (AR)...
December 27, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28018401/systemic-responses-of-barley-to-the-3-hydroxy-decanoyl-homoserine-lactone-producing-plant-beneficial-endophyte-acidovorax-radicis-n35
#7
Shengcai Han, Dan Li, Eva Trost, Klaus F Mayer, A Corina Vlot, Werner Heller, Michael Schmid, Anton Hartmann, Michael Rothballer
Quorum sensing auto-inducers of the N-acyl homoserine lactone (AHL) type produced by Gram-negative bacteria have different effects on plants including stimulation on root growth and/or priming or acquirement of systemic resistance in plants. In this communication the influence of AHL production of the plant growth promoting endophytic rhizosphere bacterium Acidovorax radicis N35 on barley seedlings was investigated. A. radicis N35 produces 3-hydroxy-C10-homoserine lactone (3-OH-C10-HSL) as the major AHL compound...
2016: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28005941/norlichexanthone-reduces-virulence-gene-expression-and-biofilm-formation-in-staphylococcus-aureus
#8
Mara Baldry, Anita Nielsen, Martin S Bojer, Yu Zhao, Cathrine Friberg, Dan Ifrah, Nina Glasser Heede, Thomas O Larsen, Hanne Frøkiær, Dorte Frees, Lixin Zhang, Huanqin Dai, Hanne Ingmer
Staphylococcus aureus is a serious human pathogen and antibiotic resistant, community-associated strains, such as the methicillin resistant S. aureus (MRSA) strain USA300, continue to spread. To avoid resistance, anti-virulence therapy has been proposed where toxicity is targeted rather than viability. Previously we have shown that norlichexanthone, a small non-reduced tricyclic polyketide produced by fungi and lichens, reduces expression of hla encoding α-hemolysin as well as the regulatory RNAIII of the agr quorum sensing system in S...
2016: PloS One
https://www.readbyqxmd.com/read/28004368/control-of-the-pollution-of-antibiotic-resistance-genes-in-soils-by-quorum-sensing-inhibition
#9
Bai-Min Lai, Kun Zhang, Dong-Sheng Shen, Mei-Zhen Wang, Jia-Li Shentu, Na Li
To investigate whether pollution from antibiotic resistance genes (ARGs) could be affected by bacterial quorum sensing, the oxytetracycline (OTC)-containing manure was fertilized to establish the ARG-polluted soil environment. Under long-term OTC stress, substantial ARGs in the range from 10(-4) to 10(-3) RG/16S rRNA (resistance genes/16S rRNA) were detected in the antibiotics control (AC) group, in which OTC-containing manure was fertilized. Meanwhile, 10(-6) RG/16S rRNA was detected in biological control (BC) group, in which non-OTC-containing manure was fertilized...
December 21, 2016: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28003734/debs-a-unification-theory-for-dry-eye-and-blepharitis
#10
James M Rynerson, Henry D Perry
For many years, blepharitis and dry eye disease have been thought to be two distinct diseases, and evaporative dry eye distinct from aqueous insufficiency. In this treatise, we propose a new way of looking at dry eye, both evaporative and insufficiency, as the natural sequelae of decades of chronic blepharitis. Dry eye is simply the late form and late manifestation of one disease, blepharitis. We suggest the use of a new term in describing this one chronic disease, namely dry eye blepharitis syndrome (DEBS)...
2016: Clinical Ophthalmology
https://www.readbyqxmd.com/read/27991530/comparative-metagenomics-reveals-taxonomically-idiosyncratic-yet-functionally-congruent-communities-in-periodontitis
#11
Shareef M Dabdoub, Sukirth M Ganesan, Purnima S Kumar
The phylogenetic characteristics of microbial communities associated with periodontitis have been well studied, however, little is known about the functional endowments of this ecosystem. The present study examined 73 microbial assemblages from 25 individuals with generalized chronic periodontitis and 25 periodontally healthy individuals using whole genome shotgun sequencing. Core metabolic networks were computed from taxa and genes identified in at least 80% of individuals in each group. 50% of genes and species identified in health formed part of the core microbiome, while the disease-associated core microbiome contained 33% of genes and only 1% of taxa...
December 19, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27981238/new-insights-into-autoinducer-2-signaling-as-a-virulence-regulator-in-a-mouse-model-of-pneumonic-plague
#12
Eric C Fitts, Jourdan A Andersson, Michelle L Kirtley, Jian Sha, Tatiana E Erova, Sadhana Chauhan, Vladimir L Motin, Ashok K Chopra
The Enterobacteriaceae family members, including the infamous Yersinia pestis, the causative agent of plague, have a highly conserved interbacterial signaling system that is mediated by the autoinducer-2 (AI-2) quorum-sensing molecule. The AI-2 system is implicated in regulating various bacterial virulence genes in diverse environmental niches. Deletion of the gene encoding the synthetic enzyme for the AI-2 substrate, luxS, leads to either no significant change or, paradoxically, an increase in in vivo bacterial virulence...
November 2016: MSphere
https://www.readbyqxmd.com/read/27980856/effect-of-rpon-rpos-and-luxs-pathways-on-the-biofilm-formation-and-antibiotic-sensitivity-of-borrelia-burgdorferi
#13
Eva Sapi, Priyanka A S Theophilus, Truc V Pham, Divya Burugu, David F Luecke
Borrelia burgdorferi, the causative agent of Lyme disease, is capable of forming biofilm in vivo and in vitro, a structure well known for its resistance to antimicrobial agents. For the formation of biofilm, signaling processes are required to communicate with the surrounding environment such as it was shown for the RpoN-RpoS alternative sigma factor and for the LuxS quorum-sensing pathways. Therefore, in this study, the wild-type B. burgdorferi and different mutant strains lacking RpoN, RpoS, and LuxS genes were studied for their growth characteristic and development of biofilm structures and markers as well as for their antibiotic sensitivity...
December 1, 2016: European Journal of Microbiology & Immunology
https://www.readbyqxmd.com/read/27942357/the-effect-of-ferula-assa-foetida-l-and-carum-copticum-hydroalcoholic-extract-on-the-expression-levels-of-staphylococcus-aureus-genes-involved-in-quorum-sensing
#14
Najmeh Jomehpour, Gilda Eslami, Mohammad Bagher Khalili
BACKGROUND: Quorum sensing is a microbial cell-to-cell communication process. Quorum sensing bacteria produce and release extracellular messenger molecules called autoinducers. Gram-positive and Gram-negative, homoserine lactones, and oligopeptides are autoinducers used to communicate and regulate gene expression. OBJECTIVES: The goal of this study was to assess the impact of subinhibitory concentrations of Ferula assa-foetida l oleo-gum resin and Carum copticum fruit on the expression of tst and hld genes of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S...
October 2016: Jundishapur Journal of Microbiology
https://www.readbyqxmd.com/read/27915294/insightful-directed-evolution-of-escherichia-coli-quorum-sensing-promoter-region-of-the-lsracdbfg-operon-a-tool-for-synthetic-biology-systems-and-protein-expression
#15
Pricila Hauk, Kristina Stephens, Ryan Mckay, Chelsea Ryan Virgile, Hana Ueda, Marc Ostermeier, Kyoung-Seok Ryu, Herman O Sintim, William E Bentley
Quorum sensing (QS) regulates many natural phenotypes (e.q. virulence, biofilm formation, antibiotic resistance), and its components, when incorporated into synthetic genetic circuits, enable user-directed phenotypes. We created a library of Escherichia coli lsr operon promoters using error-prone PCR (ePCR) and selected for promoters that provided E. coli with higher tetracycline resistance over the native promoter when placed upstream of the tet(C) gene. Among the fourteen clones identified, we found several mutations in the binding sites of QS repressor, LsrR...
December 1, 2016: Nucleic Acids Research
https://www.readbyqxmd.com/read/27907154/pheromone-recognition-and-selectivity-by-comr-proteins-among-streptococcus-species
#16
Erin Shanker, Donald A Morrison, Antoine Talagas, Sylvie Nessler, Michael J Federle, Gerd Prehna
Natural transformation, or competence, is an ability inherent to bacteria for the uptake of extracellular DNA. This process is central to bacterial evolution and allows for the rapid acquirement of new traits, such as antibiotic resistance in pathogenic microorganisms. For the Gram-positive bacteria genus Streptococcus, genes required for competence are under the regulation of quorum sensing (QS) mediated by peptide pheromones. One such system, ComRS, consists of a peptide (ComS) that is processed (XIP), secreted, and later imported into the cytoplasm, where it binds and activates the transcription factor ComR...
December 2016: PLoS Pathogens
https://www.readbyqxmd.com/read/27902410/inhibition-of-quorum-sensing-controlled-virulence-factors-of-pseudomonas-aeruginosa-by-murraya-koenigii-essential-oil-a-study-in-a-caenorhabditis-elegans-infectious-model
#17
P Sankar Ganesh, Ravishankar Vittal Rai
The global emergence of antibiotic-resistant strains of Pseudomonas aeruginosa poses a major threat in both hospital environments and the community. P. aeruginosa is an opportunistic human pathogen, and it also infects a wide range of model organisms including the nematode Caenorhabditis elegans. Quorum sensing (QS) mediates cell-to-cell communication in bacteria and has an important role in regulating virulence genes, antibiotic resistance and biofilm formation, which are crucial for establishment of the infection...
December 2016: Journal of Medical Microbiology
https://www.readbyqxmd.com/read/27892495/quorum-regulated-resistance-of-vibrio-cholerae-against-environmental-bacteriophages
#18
M Mozammel Hoque, Iftekhar Bin Naser, S M Nayeemul Bari, Jun Zhu, John J Mekalanos, Shah M Faruque
Predation by bacteriophages can significantly influence the population structure of bacterial communities. Vibrio cholerae the causative agent of cholera epidemics interacts with numerous phages in the aquatic ecosystem, and in the intestine of cholera patients. Seasonal epidemics of cholera reportedly collapse due to predation of the pathogen by phages. However, it is not clear how sufficient number of the bacteria survive to seed the environment in the subsequent epidemic season. We found that bacterial cell density-dependent gene expression termed "quorum sensing" which is regulated by signal molecules called autoinducers (AIs) can protect V...
November 28, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27864804/activity-of-norspermidine-on-bacterial-biofilms-of-multidrug-resistant-clinical-isolates-associated-with-persistent-extremity-wound-infections
#19
Anthony P Cardile, Ronald L Woodbury, Carlos J Sanchez, Sandra C Becerra, Rebecca A Garcia, Katrin Mende, Joseph C Wenke, Kevin S Akers
Biofilm formation is a major virulence factor for numerous pathogenic bacteria and is cited as a central event in the pathogenesis of chronic human infections, which is in large part due to excessive extracellular matrix secretion and metabolic changes that occur within the biofilm rendering them highly tolerant to antimicrobial treatments. Polyamines, including norspermidine, play central roles in bacterial biofilm development, but have also recently been shown to inhibit biofilm formation in select strains of various pathogenic bacteria...
November 19, 2016: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/27849583/quorum-sensing-controls-the-pseudomonas-aeruginosa-crispr-cas-adaptive-immune-system
#20
Nina M Høyland-Kroghsbo, Jon Paczkowski, Sampriti Mukherjee, Jenny Broniewski, Edze Westra, Joseph Bondy-Denomy, Bonnie L Bassler
CRISPR-Cas are prokaryotic adaptive immune systems that provide protection against bacteriophage (phage) and other parasites. Little is known about how CRISPR-Cas systems are regulated, preventing prediction of phage dynamics in nature and manipulation of phage resistance in clinical settings. Here, we show that the bacterium Pseudomonas aeruginosa PA14 uses the cell-cell communication process, called quorum sensing, to activate cas gene expression, to increase CRISPR-Cas targeting of foreign DNA, and to promote CRISPR adaptation, all at high cell density...
November 14, 2016: Proceedings of the National Academy of Sciences of the United States of America
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