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quorum sensing and resistence gene

Weiwei Dong, Jie Zhu, Xiang Guo, Delong Kong, Qi Zhang, Yiqing Zhou, Xiaoyang Liu, Shumiao Zhao, Zhiyong Ruan
N-Acyl homoserine lactones (AHLs) act as the key quorum sensing (QS) signal molecules in gram-negative bacteria, which coordinates gene expression and then activates various processes, including biofilm formation and production of virulence factors in some pathogens. Quorum quenching (QQ), which is the inactivation of the signal molecules by means of enzymatic degradation or modification, inhibits the processes of QS rather than killing the pathogens and is a promising antipathogenic strategy to control the bacterial pathogens...
April 16, 2018: Scientific Reports
Kannan Rama Devi, Subramaniyan Srinivasan, Arumugam Veera Ravi
Serratia marcescens is an opportunistic human pathogen causing various nosocomial infections, most importantly urinary tract infections (UTIs). It exhibits increased resistance towards the conventional antibiotics. This study was aimed to evaluate the anti-virulence effect of a rhizosphere soil bacterium Bacillus subtilis strain R-18 against the uropathogen S. marcescens. First, the bacterial cell-free culture supernatant (CFCS) of B. subtilis strain R-18 was evaluated for its quorum sensing inhibitory (QSI) potential against biomarker strain Chromobacterium violaceum and the test pathogen S...
April 13, 2018: Microbial Pathogenesis
Sajad Ahmad Padder, Rajendra Prasad, Abdul Haseeb Shah
Quorum sensing (QS), a density-dependent signaling mechanism of microbial cells, involves an exchange and sense of low molecular weight signaling compounds called autoinducers. With the increase in population density, the autoinducers accumulate in the extracellular environment and once their concentration reaches a threshold, many genes are either expressed or repressed. This cell density-dependent signaling mechanism enables single cells to behave as multicellular organisms and regulates different microbial behaviors like morphogenesis, pathogenesis, competence, biofilm formation, bioluminescence, etc guided by environmental cues...
May 2018: Microbiological Research
Dinesh Kumar Mehta, Rina Das
Continued emergence and spread of multidrug- resistant bacteria behooved the development of alternative treatment strategies, including antimicrobial drugs. A hopeful approach is to target cell-to-cell communications, commonly known as quorum-sensing (QS) and microbial biofilm formation. Quorum Sensing is machinery used by bacteria to determine their physiological behavior and coordinate gene expression based on the cell to cell signaling. Many physiological functions of bacteria are controlled by quorum sensings such as virulence, motility, sporulation, luminescence, and biofilm formation...
April 5, 2018: Current Drug Targets
Jailton Lobo da Costa Lima, Lilian Rodrigues Alves, Paula Regina Luna de Araújo Jacomé, João Pacífico Bezerra Neto, Maria Amélia Vieira Maciel, Marcia Maria Camargo de Morais
INTRODUCTION: Biofilm production is an important mechanism for the survival of Pseudomonas aeruginosa and its relationship with antimicrobial resistance represents a challenge for patient therapeutics. P. aeruginosa is an opportunistic pathogen frequently associated to nosocomial infections, especially in imunocompromised hosts. OBJECTIVES: Analyze the phenotypic biofilm production in P. aeruginosa isolates, describe clonal profiles, and analyze quorum sensing (QS) genes and the occurrence of mutations in the LasR protein of non-biofilm producing isolates...
March 27, 2018: Brazilian Journal of Infectious Diseases
Johannes Arp, Sebastian Götze, Ruchira Mukherji, Derek J Mattern, María García-Altares, Martin Klapper, Debra A Brock, Axel A Brakhage, Joan E Strassmann, David C Queller, Bettina Bardl, Karsten Willing, Gundela Peschel, Pierre Stallforth
Investigating microbial interactions from an ecological perspective is a particularly fruitful approach to unveil both new chemistry and bioactivity. Microbial predator-prey interactions in particular rely on natural products as signal or defense molecules. In this context, we identified a grazing-resistant Pseudomonas strain, isolated from the bacterivorous amoeba Dictyostelium discoideum. Genome analysis of this bacterium revealed the presence of two biosynthetic gene clusters that were found adjacent to each other on a contiguous stretch of the bacterial genome...
March 28, 2018: Proceedings of the National Academy of Sciences of the United States of America
Xiangyu Ju, Junjie Li, Mengjiao Zhu, Zhaoxin Lu, Fengxia Lv, Xiaoyu Zhu, Xiaomei Bie
Biofilms are communities of bacterial cells that serve to protect them from external adverse influences and enhance bacterial resistance to antibiotics and sanitizers. Here, we studied the regulatory effects of glucose and sodium chloride on biofilm formation in Salmonella serovar Dublin (S. Dublin). To analyze expression levels of the quorum sensing gene luxS, we created a luxS knockout mutant. Also, antimicrobial resistance, hydrophobicity and autoinducer-2 (AI-2) activity of both the wild-type (WT) and the mutant strain were investigated...
May 2018: Food Research International
Artemis Gogos, Juan Cristobal Jimenez, Jennifer C Chang, Reid V Wilkening, Michael J Federle
The Rgg2/3 quorum sensing (QS) system is conserved among all sequenced isolates of Group A Streptococcus (GAS, Streptococcus pyogenes ). The molecular architecture of the system consists of a transcriptional activator (Rgg2) and a transcriptional repressor (Rgg3) under the control of autoinducing peptide pheromones (SHP2 and SHP3). Activation of the Rgg2/3 pathway leads to increases in biofilm formation and resistance to the bactericidal effects of the host factor, lysozyme. In this work, we show that deletion of a small gene, Spy49_0414c , abolished both phenotypes in response to pheromone signaling...
March 19, 2018: Journal of Bacteriology
Angharad E Green, Alejandro Amézquita, Yvan Le-Marc, Matthew J Bull, Thomas R Connor, Eshwar Mahenthiralingam
Pseudomonas aeruginosa (P. aeruginosa) is a common contaminant associated with product recalls in the home and personal care (HPC) industry. Preservation systems are used to prevent spoilage and protect consumers, but greater knowledge is needed of preservative resistance mechanisms used by P. aeruginosa contaminants. We aimed to identify genetic pathways associated with preservative exposure by using an industrial P. aeruginosa strain and implementing RNA-Seq to understand gene expression changes in response to industry relevant conditions...
March 14, 2018: FEMS Microbiology Letters
Jin-Wei Zhou, Tong-Tong Chen, Xiao-Juan Tan, Ji-Yang Sheng, Ai-Qun Jia
Pseudomonas aeruginosa infection is a serious disease in cystic fibrosis (CF) patients and is difficult to cure due to biofilm persistence and emerging multidrug resistance. Considering the essential role of quorum sensing (QS) in P. aeruginosa infections, the enhanced effects between quorum sensing inhibitor (QSI) resveratrol and several antibiotics against P. aeruginosa PAO1 were investigated. Crystal violet staining assay revealed that the biofilms of P. aeruginosa PAO1 grown in the presence of resveratrol were more susceptible to aminoglycoside antibiotics...
March 9, 2018: International Journal of Antimicrobial Agents
Ying Zhou, Chao Niu, Bo Ma, Xiaoyan Xue, Zhi Li, Zhou Chen, Fen Li, Shan Zhou, Xiaoxing Luo, Zheng Hou
Given its high resistance, enhanced virulence, and high transmissibility, community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) pneumonia is highly associated with high morbidity and mortality. Anti-virulence therapy is a promising strategy that bypasses the evolutionary pressure on the bacterium to develop resistance. RNAIII-inhibiting peptide (RIP), as an accessory gene regulator (agr)-specific inhibitor, significantly restricts the virulence of S. aureus and protects infected mice from death by blocking the agr quorum sensing system...
March 2, 2018: Cell Death & Disease
Ankita Vaishampayan, Anne de Jong, Darren J Wight, Jan Kok, Elisabeth Grohmann
Methicillin-resistant Staphylococcus aureus (MRSA) has become an important cause of hospital-acquired infections worldwide. It is one of the most threatening pathogens due to its multi-drug resistance and strong biofilm-forming capacity. Thus, there is an urgent need for novel alternative strategies to combat bacterial infections. Recently, we demonstrated that a novel antimicrobial surface coating, AGXX® , consisting of micro-galvanic elements of the two noble metals, silver and ruthenium, surface-conditioned with ascorbic acid, efficiently inhibits MRSA growth...
2018: Frontiers in Microbiology
Georgia Karathanasi, Martin Saxtorph Bojer, Mara Baldry, Bárdur Andréson Johannessen, Sanne Wolff, Ines Greco, Mogens Kilstrup, Paul Robert Hansen, Hanne Ingmer
Staphylococcus aureus is an important pathogen causing infections in humans and animals. Increasing problems with antimicrobial resistance has prompted the development of alternative treatment strategies, including antivirulence approaches targeting virulence regulation such as the agr quorum sensing system. agr is naturally induced by cyclic auto-inducing peptides (AIPs) binding to the AgrC receptor and cyclic peptide inhibitors have been identified competing with AIP binding to AgrC. Here, we disclose that small, linear peptidomimetics can act as specific and potent inhibitors of the S...
February 23, 2018: Scientific Reports
Xiaoxiang Liu, Lei Ji, Xu Wang, Jianrong Li, Junli Zhu, Aihua Sun
Microorganism activities are considered the main cause of most food spoilage, leading to great economic losses. Pseudomonas fluorescens is a Gram-negative bacterium that is widely found in food and has high spoilage activity. RpoS is considered an important global regulator involved in stress survival and virulence in many pathogens. Thus, it is very possible that RpoS plays an important role in spoilage regulation in P. fluorescens. In this study an in-frame deletion mutation of rpoS was constructed to explore its function in P...
February 14, 2018: International Journal of Food Microbiology
Annamária Kincses, Borisz Varga, Ákos Csonka, Shirley Sancha, Silva Mulhovo, Ana Margarida Madureira, Maria-José U Ferreira, Gabriella Spengler
Cleistochlamys kirkii (Benth) Oliv. (Annonaceae) is a medicinal plant traditionally used in Mozambique to treat infectious diseases. The aim of this study was to find resistance modifiers in C. kirkii for Gram-positive and Gram-negative model bacterial strains. One of the most important resistance mechanisms in bacteria is the efflux pump-related multidrug resistance. Therefore, polycarpol (1), three C-benzylated flavanones (2-4), and acetylmelodorinol (5) were evaluated for their multidrug resistance-reverting activity on methicillin-susceptible and methicillin-resistant Staphylococcus aureus and Escherichia coli AG100 and AG100 A strains overexpressing and lacking the AcrAB-TolC efflux pump system...
February 21, 2018: Phytotherapy Research: PTR
Zhangjian Hu, Shujun Shao, Chenfei Zheng, Zenghui Sun, Junying Shi, Jingquan Yu, Zhenyu Qi, Kai Shi
N-decanoyl-homoserine lactone activates plant systemic resistance against Botrytis cinerea in tomato plants, which is largely dependent on jasmonic acid biosynthesis and signal transduction pathways. Rhizosphere bacteria secrete N-acylated-homoserine lactones (AHLs), a type of specialized quorum-sensing signal molecule, to coordinate their population density during communication with their eukaryotic hosts. AHLs behave as low molecular weight ligands that are sensed by plants and promote the host's resistance against foliar pathogens...
February 14, 2018: Planta
Durgadevi Ravindran, Srinivasan Ramanathan, Kannappan Arunachalam, Godfred Ponraj Jeyaraj, Karutha Pandian Shunmugiah, Veera Ravi Arumugam
AIM: Serratia marcescens is an important multidrug-resistant human pathogen. The pathogenicity of S. marcescens mainly depends on the Quorum Sensing (QS) mechanism, which regulates the virulence factors production and biofilm formation. Hence, targeting QS mechanism in S. marcescens will ultimately pave the way to combat its pathogenicity. Thus, the present study is intended to evaluate the efficacy of Vetiveria zizanioides root extract mediated silver nanoparticles (AgNPs) as a potent anti-QS and antibiofilm agent against S...
February 12, 2018: Journal of Applied Microbiology
Daniela Santos Pontes, Rodrigo Santos Aquino de Araujo, Natalina Dantas, Luciana Scotti, Marcus Tullius Scotti, Ricardo Olimpio de Moura, Francisco Jaime Bezerra Mendonca-Junior
The ever increasing number of multidrug-resistant microorganism pathogens has become a great and global public health threat. Antibiotic mechanisms of action and the opposing mechanisms of resistance are intimately associated, but comprehension of the biochemical and molecular functions of such drugs is not a simple exercise. Both the environment, and genetic settings contribute to alterations in phenotypic resistance (natural bacterial evolution), and make it difficult to control the emergence and impacts of antibiotic resistance...
February 5, 2018: Current Topics in Medicinal Chemistry
Byoung Sik Kim, Song Yee Jang, Ye-Ji Bang, Jungwon Hwang, Youngwon Koo, Kyung Ku Jang, Dongyeol Lim, Myung Hee Kim, Sang Ho Choi
Pathogenic Vibrio species cause diseases in diverse marine animals reared in aquaculture. Since their pathogenesis, persistence, and survival in marine environments are regulated by quorum sensing (QS), QS interference has attracted attention as a means to control these bacteria in aquatic settings. A few QS inhibitors of Vibrio species have been reported, but detailed molecular mechanisms are lacking. Here, we identified a novel, potent, and selective Vibrio QS inhibitor, named QStatin [1-(5-bromothiophene-2-sulfonyl)-1H-pyrazole], which affects Vibrio harveyi LuxR homologues, the well-conserved master transcriptional regulators for QS in Vibrio species...
January 30, 2018: MBio
Akram M Salam, Cassandra L Quave
Methicillin-resistant Staphylococcus aureus (MRSA) presents one of the most serious health concerns worldwide. The WHO labeled it as a "high-priority" pathogen in 2017, also citing the more recently emerged vancomycin-intermediate and -resistant strains. With the spread of antibiotic resistance due in large part to the selective pressure exerted by conventional antibiotics, the use of antivirulence strategies has been recurrently proposed as a promising therapeutic approach. In MRSA, virulence is chiefly controlled by quorum sensing (QS); inhibitors of QS are called quorum quenchers (QQ)...
January 2018: MSphere
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