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lipopolysaccharide and biofilm formation

Ranita Roy, Monalisa Tiwari, Gianfranco Donelli, Vishvanath Tiwari
Biofilm refers to the complex, sessile communities of microbes found either attached to a surface or buried firmly in an extracellular matrix as aggregates. The biofilm matrix surrounding bacteria makes them tolerant to harsh conditions and resistant to antibacterial treatments. Moreover, the biofilms are responsible for causing a broad range of chronic diseases and due to the emergence of antibiotic resistance in bacteria it has really become difficult to treat them with efficacy. Furthermore, the antibiotics available till date are ineffective for treating these biofilm related infections due to their higher values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which may result in in-vivo toxicity...
March 31, 2017: Virulence
Sandro Roier, Franz G Zingl, Fatih Cakar, Stefan Schild
Outer membrane vesicle (OMV) release by Gram-negative bacteria has been observed and studied for decades. First considered as a by-product of cell lysis, it soon became evident that OMVs are actively secreted from the outer membrane (OM) of Gram-negative bacteria. Accordingly, these small particles (~ 10-300 nm in diameter) consist mainly of OM components like phospholipids (PLs), OM proteins, and lipopolysaccharides or lipooligosaccharides. However, OMVs may also comprise periplasmic, inner membrane, or cytoplasmic components...
May 10, 2016: Microbial Cell
Kourtney P Nickerson, Rachael B Chanin, Jeticia R Sistrunk, David A Rasko, Peter J Fink, Eileen M Barry, James P Nataro, Christina S Faherty
The Shigella species cause millions of cases of watery or bloody diarrhea each year, mostly in children in developing countries. While many aspects of Shigella colonic cell invasion are known, crucial gaps in knowledge remain regarding how the bacteria survive, transit, and regulate gene expression prior to infection. In this study, we define mechanisms of bile salts resistance and build on previous research highlighting induced virulence in S. flexneri strain 2457T following bile salts exposure. Typical growth patterns were observed within the physiological range of bile salts; however, growth was inhibited at higher concentrations...
March 27, 2017: Infection and Immunity
Marco Giannelli, Giulia Landini, Fabrizio Materassi, Flaminia Chellini, Alberto Antonelli, Alessia Tani, Daniele Nosi, Sandra Zecchi-Orlandini, Gian Maria Rossolini, Daniele Bani
Effective decontamination of biofilm and bacterial toxins from the surface of dental implants is a yet unresolved issue. This study investigates the in vitro efficacy of photodynamic treatment (PDT) with methylene blue (MB) photoactivated with λ 635 nm diode laser and of λ 405 nm violet-blue LED phototreatment for the reduction of bacterial biofilm and lipopolysaccharide (LPS) adherent to titanium surface mimicking the bone-implant interface. Staphylococcus aureus biofilm grown on titanium discs with a moderately rough surface was subjected to either PDT (0...
March 10, 2017: Lasers in Medical Science
Daniel Pletzer, Sarah C Mansour, Kelli Wuerth, Negin Rahanjam, Robert E W Hancock
Only a few, relatively cumbersome animal models enable long-term Gram-negative bacterial infections that mimic human situations, where untreated infections can last for weeks. Here, we describe a simple murine cutaneous abscess model that enables chronic or progressive infections, depending on the subcutaneously injected bacterial strain. In this model, Pseudomonas aeruginosa cystic fibrosis epidemic isolate LESB58 caused localized high-density skin and soft tissue infections and necrotic skin lesions for up to 10 days but did not disseminate in either CD-1 or C57BL/6 mice...
February 28, 2017: MBio
Toan Phuoc Hong, Michelle Q Carter, Paolo Struffi, Stefano Casonato, Youai Hao, Joseph S Lam, Stephen Lory, Olivier Jousson
BACKGROUND: Pseudomonas aeruginosa pathogenicity island 1 (PAPI-1) is one of the largest genomic islands of this important opportunistic human pathogen. Previous studies have shown that PAPI-1 encodes several putative virulence factors, including a major regulator of biofilm formation and antibiotic-resistance traits. PAPI-1 is horizontally transferable into recipient strains lacking this island via conjugation mediated by the specialized type IV pilus. The PAPI-1 encodes a cluster of ten genes associated with the synthesis and assembly of the type IV pilus...
February 7, 2017: BMC Microbiology
Eric Hong Jian Wong, Chow Goon Ng, Eng Guan Chua, Alfred Chin Yen Tay, Fanny Peters, Barry J Marshall, Bow Ho, Khean Lee Goh, Jamuna Vadivelu, Mun Fai Loke
BACKGROUND: Biofilm formation by Helicobacter pylori may be one of the factors influencing eradication outcome. However, genetic differences between good and poor biofilm forming strains have not been studied. MATERIALS AND METHODS: Biofilm yield of 32 Helicobacter pylori strains (standard strain and 31 clinical strains) were determined by crystal-violet assay and grouped into poor, moderate and good biofilm forming groups. Whole genome sequencing of these 32 clinical strains was performed on the Illumina MiSeq platform...
2016: PloS One
Wei Zhou, Xuan Zhang, Cai-Lian Zhu, Zhi-Yan He, Jing-Ping Liang, Zhong-Chen Song
AIM: "Perioceutics" including antimicrobial therapy and host modulatory therapy has emerged as a vital adjunctive treatment of periodontal disease. Melatonin level was significantly reduced in patients with periodontal diseases suggesting melatonin could be applied as a potential "perioceutics" treatment of periodontal diseases. This study aims to investigate the effects of melatonin receptor agonists (melatonin and ramelteon) on Porphyromonas gingivalis virulence and Porphyromonas gingivalis-derived lipopolysaccharide (Pg-LPS)-induced inflammation...
2016: PloS One
Inês N Silva, Pedro M Santos, Mário R Santos, James E A Zlosnik, David P Speert, Sean W Buskirk, Eric L Bruger, Christopher M Waters, Vaughn S Cooper, Leonilde M Moreira
Burkholderia multivorans is an opportunistic pathogen capable of causing severe disease in patients with cystic fibrosis (CF). Patients may be chronically infected for years, during which the bacterial population evolves in response to unknown forces. Here we analyze the genomic and functional evolution of a B. multivorans infection that was sequentially sampled from a CF patient over 20 years. The population diversified into at least four primary, coexisting clades with distinct evolutionary dynamics. The average substitution rate was only 2...
May 2016: MSystems
M S Abu-Darwish, C Cabral, M J Gonçalves, C Cavaleiro, M T Cruz, M Paoli, F Tomi, T Efferth, L Salgueiro
ETHNOPHARMACOLOGIC RELEVANCE: Ziziphora tenuior L. (Lamiaceae) is a medicinal plant in Jordan, which is included in various antimicrobial, antiseptic, expectorant and wound healing preparations. It is used for the treatment of cough, stomach ache, dysentery, fever, uterus infection, gut inflammation and painful menstruation. AIM OF THE STUDY: The aim of this study was to assess, for the first time, the chemical composition of the essential oil of Z. tenuior originated from southern Jordan and its antifungal effects against several yeasts...
December 24, 2016: Journal of Ethnopharmacology
Sebastián Acosta-Jurado, Pilar Navarro-Gómez, Piedad Del Socorro Murdoch, Juan-Carlos Crespo-Rivas, Shi Jie, Lidia Cuesta-Berrio, José-Enrique Ruiz-Sainz, Miguel-Ángel Rodríguez-Carvajal, José-María Vinardell
In the rhizobia-legume symbiotic interaction, bacterial surface polysaccharides, such as exopolysaccharide (EPS), lipopolysaccharide (LPS), K-antigen polysaccharide (KPS) or cyclic glucans (CG), appear to play crucial roles either acting as signals required for the progression of the interaction and/or preventing host defence mechanisms. The symbiotic significance of each of these polysaccharides varies depending on the specific rhizobia-legume couple. In this work we show that the production of exopolysaccharide by Sinorhizobium fredii HH103, but not by other S...
2016: PloS One
Dan Xu, Wei Zhang, Bing Zhang, Chongbing Liao, Yongping Shao
Deficiency in biosynthesis of inner core of lipopolysaccharide (LPS) rendered a characteristic biofilm-forming phenotype in E. coli. The pathological implications of this new phenotype in Shigella flexneri, a highly contagious enteric Gram-negative bacteria that is closely related to E. coli, were investigated in this study. The ΔrfaC (also referred as waaC) mutant, with incomplete inner core of LPS due to deficiency in Hep biosynthesis, was characteristic of strong biofilm formation ability and exhibited much more pronounced adhesiveness and invasiveness to human epithelial cells than the parental strain and other LPS mutants, which also showed distinct pattern of F-actin recruitment...
2016: PeerJ
E Shumilova, A V Shelud'ko, Yu A Filip'echeva, S S Evstigneeva, E G Ponomareva, L P Petrova, E I Katsy
The previously obtained insertion mutants ofAzospirillum brasilense Sp245 in the genes mmsBl and fabG1 (strains SK039 and Sp245.1610, respectively) were characterized by impaired flagellation and motility. The putative products of expression of these genes are 3-hydroxyisobutyrate dehydrogenase and 3-oxoacyl-[acyl-carrier protein] reductase, respectively. In the present work, A. brasilense- Sp245 strains SK039 and Sp245.1610 were found to have differences in the content of 3-hydroxyhexadecanoic, hexadecanoic, 3-hydroxytetradecanoic, hexadecenoic, octadecenoic, and nonadecanoic acids in their lipopolysaccharide prepa- rations, as well as in cell hydrophobicity and hemagglutination activity and dynamics of cell aggregation, in biomass amount, and in the relative content of lipopolysaccharide antigens in mature biofilms formed on hydrophilic or hydrophobic surfaces...
March 2016: Mikrobiologiia
Kyung-Jo Lee, Mi-Ae Lee, Won Hwang, Hana Park, Kyu-Ho Lee
The extracellular polysaccharides of Vibrio vulnificus play different roles during biofilm development. Among them, the effect of lipopolysaccharide (LPS), which is crucial for bacterial adherence to surfaces during the initial stage of biofilm formation, on the formation process was examined using various types of LPS extracts. Exogenously added LPS strongly inhibited biofilm formation in a dose-dependent manner. In addition, the exogenous addition of a deacylated form of LPS (dLPS) also inhibited biofilm formation...
August 2016: Biofouling
Grzegorz Czerwonka, Anna Guzy, Klaudia Kałuża, Michalina Grosicka, Magdalena Dańczuk, Łukasz Lechowicz, Dawid Gmiter, Paweł Kowalczyk, Wiesław Kaca
Biofilms formed by Proteus mirabilis strains are a serious medical problem, especially in the case of urinary tract infections. Early stages of biofilm formation, such as reversible and irreversible adhesion, are essential for bacteria to form biofilm and avoid eradication by antibiotic therapy. Adhesion to solid surfaces is a complex process where numerous factors play a role, where hydrophobic and electrostatic interactions with solid surface seem to be substantial. Cell surface hydrophobicity and electrokinetic potential of bacterial cells depend on their surface composition and structure, where lipopolysaccharide, in Gram-negative bacteria, is prevailing...
November 2016: Archives of Microbiology
Agustín Reyes-Pérez, María Del Carmen Vargas, Magdalena Hernández, Eneas Aguirre-von-Wobeser, Ernesto Pérez-Rueda, Sergio Encarnacion
Organisms belonging to the genus Rhizobium colonize leguminous plant roots and establish a mutually beneficial symbiosis. Biofilms are structured ecosystems in which microbes are embedded in a matrix of extracellular polymeric substances, and their development is a multistep process. The biofilm formation processes of R. etli CFN42 were analyzed at an early (24-h incubation) and mature stage (72 h), comparing cells in the biofilm with cells remaining in the planktonic stage. A genome-wide microarray analysis identified 498 differentially regulated genes, implying that expression of ~8...
November 2016: Archives of Microbiology
Murali Sharaff, G Archana
Cu is an essential micronutrient required during nitrogen fixation, but above threshold concentrations it becomes toxic. The present study was aimed at studying the effect of high Cu concentrations on the early plant-microbe interactions between Ensifer (Sinorhizobium) meliloti 1021, a symbiotic diazotrophic bacterium belonging to α-Proteobacteria, and its plant host Medicago truncatula. E. meliloti exhibited pleomorphism with elongated and branched growth at 100 µM Cu which brought about 50 % reduction in growth...
September 2016: Archives of Microbiology
Lei Liu, Haihong Fang, Huiying Yang, Yiquan Zhang, Yanping Han, Dongsheng Zhou, Ruifu Yang
gmhA encodes a phosphoheptose isomerase that catalyzes the biosynthesis of heptose, a conserved component of lipopolysaccharide (LPS). GmhA plays an important role in Yersinia pestis biofilm blockage in the flea gut. waaA, waaE, and coaD constitute a three-gene operon waaAE-coaD in Y. pestis. waaA encodes a transferase that is responsible for binding lipid-A to the core oligosaccharide of LPS. WaaA is a key determinant in Y. pestis biofilm formation, and the waaA expression is positively regulated by the two-component regulatory system PhoP/PhoQ...
2016: Frontiers in Microbiology
Wee S Lim, Kevin K S Phang, Andy H-M Tan, Sam F-Y Li, Dave S-W Ow
Phage therapy involves the application of lytic bacteriophages for treatment of clinical infections but bacterial resistance may develop over time. Isolated from nosocomial infections, small colony variants (SCVs) are morphologically distinct, highly virulent bacterial strains that are resistant to conventional antibiotics. In this study, SCVs was derived from Pseudomonas aeruginosa exposed to the lytic bacteriophage PB1 and these cells were resistant to subsequent phage infection by PB1. To elucidate the mechanism of the SCV phage resistance, we performed phenotypic assays, DNA microarrays and whole-genome sequencing...
2016: Frontiers in Microbiology
Steven Clegg, Caitlin N Murphy
Strains of Klebsiella pneumoniae are frequently opportunistic pathogens implicated in urinary tract and catheter-associated urinary-tract infections of hospitalized patients and compromised individuals. Infections are particularly difficult to treat since most clinical isolates exhibit resistance to several antibiotics leading to treatment failure and the possibility of systemic dissemination. Infections of medical devices such as urinary catheters is a major site of K. pneumoniae infections and has been suggested to involve the formation of biofilms on these surfaces...
February 2016: Microbiology Spectrum
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