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pathogenicity and biofilm formation

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https://www.readbyqxmd.com/read/28635589/regulation-of-escherichia-coli-pathogenesis-by-alternative-sigma-factor-n
#1
James T Riordan, Avishek Mitra
σ(N) (also σ(54)) is an alternative sigma factor subunit of the RNA polymerase complex that regulates the expression of genes from many different ontological groups. It is broadly conserved in the Eubacteria with major roles in nitrogen metabolism, membrane biogenesis, and motility. σ(N) is encoded as the first gene of a five-gene operon including rpoN (σ(N)), ptsN, hpf, rapZ, and npr that has been genetically retained among species of Escherichia, Shigella, and Salmonella. In an increasing number of bacteria, σ(N) has been implicated in the control of genes essential to pathogenic behavior, including those involved in adherence, secretion, immune subversion, biofilm formation, toxin production, and resistance to both antimicrobials and biological stressors...
June 2017: EcoSal Plus
https://www.readbyqxmd.com/read/28634301/microbial-glycoside-hydrolases-as-antibiofilm-agents-with-cross-kingdom-activity
#2
Brendan D Snarr, Perrin Baker, Natalie C Bamford, Yukiko Sato, Hong Liu, Mélanie Lehoux, Fabrice N Gravelat, Hanna Ostapska, Shane R Baistrocchi, Robert P Cerone, Elan E Filler, Matthew R Parsek, Scott G Filler, P Lynne Howell, Donald C Sheppard
Galactosaminogalactan and Pel are cationic heteropolysaccharides produced by the opportunistic pathogens Aspergillus fumigatus and Pseudomonas aeruginosa, respectively. These exopolysaccharides both contain 1,4-linked N-acetyl-d-galactosamine and play an important role in biofilm formation by these organisms. Proteins containing glycoside hydrolase domains have recently been identified within the biosynthetic pathway of each exopolysaccharide. Recombinant hydrolase domains from these proteins (Sph3h from A...
June 20, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28629757/bacterial-biofilm-based-catheter-associated-urinary-tract-infections-causative-pathogens-and-antibiotic-resistance
#3
Nargis Sabir, Aamer Ikram, Gohar Zaman, Luqman Satti, Adeel Gardezi, Abeera Ahmed, Parvez Ahmed
BACKGROUND: We sought to determine the incidence of bacterial biofilm-based catheter-associated urinary tract infections, identify variables affecting biofilm formation, and identify etiologic bacterial pathogens and antibiotic-resistance patterns associated with biofilm-based catheter-associated urinary tract infections (CAUTIs) in our setup. METHODS: Patients who developed at least 2 symptoms of urinary tract infection after at least 2 days of indwelling urinary catheters were included...
June 16, 2017: American Journal of Infection Control
https://www.readbyqxmd.com/read/28624271/coagulase-negative-staphylococci-species-affect-biofilm-formation-of-other-coagulase-negative-and-coagulase-positive-staphylococci
#4
Coralie Goetz, Yannick D N Tremblay, Daphnée Lamarche, Andréanne Blondeau, Annie M Gaudreau, Josée Labrie, François Malouin, Mario Jacques
Coagulase-negative staphylococci (CNS) are considered to be commensal bacteria in humans and animals, but are now also recognized as etiological agents in several infections, including bovine mastitis. Biofilm formation appears to be an important factor in CNS pathogenicity. Furthermore, some researchers have proposed that CNS colonization of the intramammary environment has a protective effect against other pathogens. The mechanisms behind the protective effect of CNS have yet to be characterized. The aim of this study was to evaluate the effect of CNS isolates with a weak-biofilm phenotype on the biofilm formation of other staphylococcal isolates...
June 14, 2017: Journal of Dairy Science
https://www.readbyqxmd.com/read/28620360/cytr-homolog-of-pectobacterium-carotovorum-subsp-carotovorum-controls-air-liquid-biofilm-formation-by-regulating-multiple-genes-involved-in-cellulose-production-c-di-gmp-signaling-motility-and-type-iii-secretion-system-in-response-to-nutritional-and-environmental
#5
M M Haque, M M H Oliver, Kamrun Nahar, Mohammad Z Alam, Hisae Hirata, Shinji Tsuyumu
Pectobacterium carotovorum subsp. carotovorum [Pcc (formerly Erwinia carotovora subsp. carotovora)] PC1 causes soft-rot disease in a wide variety of plant species by secreting multiple pathogenicity-related traits. In this study, regulatory mechanism of air-liquid (AL) biofilm formation was studied using a cytR homolog gene deletion mutant (ΔcytR) of Pcc PC1. Compared to the wild type (Pcc PC1), the ΔcytR mutant produced fragile and significantly (P < 0.001) lower amounts of AL biofilm on salt-optimized broth plus 2% glycerol (SOBG), yeast peptone dextrose adenine, and also on King's B at 27°C after 72 h incubation in static condition...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28617616/the-role-of-nrf2-in-the-regulation-of-periodontal-health-and-disease
#6
A V Chiu, M Al Saigh, C A McCulloch, M Glogauer
Immune-related disease tolerance is an important defense strategy that facilitates the maintenance of health in organs and tissues that are commonly colonized by bacteria. Immune tolerance to dysbiotic, tooth-borne biofilms is a poorly understood yet clinically relevant concept in the immunopathological mechanisms that are involved in the pathogenesis of periodontitis, particularly those related to neutrophil and macrophage responses. In periodontal health, neutrophils and macrophages respond to the formation of pathogenic bacterial biofilms by the production of bactericidal reactive oxygen species (ROS)...
June 1, 2017: Journal of Dental Research
https://www.readbyqxmd.com/read/28616631/the-effect-of-emodin-on-staphylococcus-aureus-strains-in-planktonic-form-and-biofilm-formation-in-vitro
#7
Xin Yan, Shanshan Gu, Yunjia Shi, Xingyang Cui, Shanshan Wen, Junwei Ge
Staphylococcus aureus (S. aureus) is a Gram-positive pathogen and forms biofilm easily. Bacteria inside biofilms display an increased resistance to antibiotics and disinfectants. The objective of the current study was to assess the antimicrobial activities of emodin, 1,2,8-trihydroxy-6-methylanthraquinone, an anthraquinone derivative isolated from Polygonum cuspidatum and Rheum palmatum, against S. aureus CMCC26003 grown in planktonic and biofilm cultures in vitro. In addition, a possible synergistic effect between emodin and berberine chloride was evaluated...
June 14, 2017: Archives of Microbiology
https://www.readbyqxmd.com/read/28615734/the-role-of-organic-acids-on-microbial-deterioration-in-the-radix-pseudostellariae-rhizosphere-under-continuous-monoculture-regimes
#8
Hongmiao Wu, Linkun Wu, Quan Zhu, Juanying Wang, Xianjin Qin, Jiahui Xu, Lufei Kong, Jun Chen, Sheng Lin, Muhammad Umar Khan, Hira Amjad, Wenxiong Lin
A three-year field monoculture trial of Radix pseudostellariae and complementary laboratory studies were conducted to further elucidate the underlying mechanism responsible for significant decreases in the biomass yield and quality of R. pseudostellariae under continuous monoculture regimes. HPLC analysis indicated that continuous monoculture soil was rich in organic acids, which had cumulative effects over time. Further analysis suggested that the application of a mixture of organic acids significantly promoted growth of pathogenic fungi, and increased the expression of chemotaxis-related gene (cheA) and biofilm formation of the specific pathogenic Kosakonia sacchari...
June 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28615078/characterisation-of-roseomonas-mucosa-isolated-from-the-root-canal-of-an-infected-tooth
#9
Nina Diesendorf, Stefanie Köhler, Walter Geißdörfer, Tanja Grobecker-Karl, Matthias Karl, Andreas Burkovski
OBJECTIVE: The genus Roseomonas comprises a group of pink-pigmented, slow-growing, aerobic, non-fermentative Gram-negative bacteria, which have been isolated from environmental sources such as water and soil, but are also associated with human infections. In the study presented here, Roseomonas mucosa was identified for the first time as part of the endodontic microbiota of an infected root canal and characterised in respect to growth, antibiotic susceptibility and biofilm formation. RESULTS: The isolated R...
June 14, 2017: BMC Research Notes
https://www.readbyqxmd.com/read/28611955/uncovering-differences-in-virulence-markers-associated-with-achromobacter-species-of-cf-and-non-cf-origin
#10
Brankica Filipic, Milka Malesevic, Zorica Vasiljevic, Jovanka Lukic, Katarina Novovic, Milan Kojic, Branko Jovcic
Achromobacter spp. are recognized as emerging pathogens in hospitalized as well as in cystic fibrosis (CF) patients. From 2012 to 2015, we collected 69 clinical isolates (41 patient) of Achromobacter spp. from 13 patients with CF (CF isolates, n = 32) and 28 patients receiving care for other health conditions (non-CF isolates, n = 37). Molecular epidemiology and virulence potential of isolates were examined. Antimicrobial susceptibility, motility, ability to form biofilms and binding affinity to mucin, collagen, and fibronectin were tested to assess their virulence traits...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28611496/a-bacteriophage-mediated-gold-nanoparticles-synthesis-and-their-anti-biofilm-activity
#11
S S Ahiwale, A V Bankar, S Tagunde, B P Kapadnis
In the present study, gold nanoparticles (AuNPs) synthesis was carried out by using a rare bacteriophage which is morphologically similar to 7-11 phages of the C3 morphotype of tailed phage belonging to Podoviridae family as green route. Effect of various physiological parameters like pH, temperature and concentration of gold chloride salt on AuNPs synthesis was studied. The reaction mixtures have shown vivid colours at various physiological parameters. Phage inspired AuNPs were further characterized by using different techniques such as UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and dynamic light scattering (DLS)...
June 2017: Indian Journal of Microbiology
https://www.readbyqxmd.com/read/28611429/streptococcus-sp-in-neonatal-endotracheal-tube-biofilms-is-associated-with-ventilator-associated-pneumonia-and-enhanced-biofilm-formation-of-pseudomonas-aeruginosa-pao1
#12
Yun Pan, Sijie Song, Xiaoli Tang, Qing Ai, Danping Zhu, Zhenqiu Liu, Jialin Yu
Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation leading to high morbidity and mortality among intubated neonates in neonatal intensive care units (NICUs). Endotracheal tube (ETT) biofilm flora were considered to be responsible for the occurrence of VAP as a reservoir of pathogens. However, regarding neonates with VAP, little is known about the complex microbial signatures in ETT biofilms. In the present study, a culture-independent approach based on next generation sequencing was performed as an initial survey to investigate the microbial communities in ETT biofilms of 49 intubated neonates with and without VAP...
June 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28611217/rna-target-profiles-direct-the-discovery-of-virulence-functions-for-the-cold-shock-proteins-cspc-and-cspe
#13
Charlotte Michaux, Erik Holmqvist, Erin Vasicek, Malvika Sharan, Lars Barquist, Alexander J Westermann, John S Gunn, Jörg Vogel
The functions of many bacterial RNA-binding proteins remain obscure because of a lack of knowledge of their cellular ligands. Although well-studied cold-shock protein A (CspA) family members are induced and function at low temperature, others are highly expressed in infection-relevant conditions. Here, we have profiled transcripts bound in vivo by the CspA family members of Salmonella enterica serovar Typhimurium to link the constitutively expressed CspC and CspE proteins with virulence pathways. Phenotypic assays in vitro demonstrated a crucial role for these proteins in membrane stress, motility, and biofilm formation...
June 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28608317/ica-status-of-clinical-staphylococcus-epidermidis-strains-affects-adhesion-and-aggregation-a-thermodynamic-analysis
#14
Titik Nuryastuti, Bastiaan P Krom
Staphylococcus epidermidis is a major nosocomial pathogen associated with infections of indwelling medical devices. One important virulence factor of these organisms is their ability to adhere to devices and form biofilms. In this study, we evaluated the effect of the ica operon on cell surface hydrophobicity, thermodynamics of adhesion, and biofilm formation for seven S. epidermidis strains. The surface free energy parameters of the bacterial cell surface and the substratum were determined by contact angle measurement...
June 12, 2017: Antonie Van Leeuwenhoek
https://www.readbyqxmd.com/read/28607158/the-two-component-signal-transduction-system-vxrab-positively-regulates-vibrio-cholerae-biofilm-formation
#15
Jennifer K Teschler, Andrew T Cheng, Fitnat H Yildiz
Two-component signal transduction systems (TCSs), typically composed of a sensor histidine kinase (HK) and a response regulator (RR), are the primary mechanism by which pathogenic bacteria sense and respond to extracellular signals. The pathogenic bacterium Vibrio cholerae is no exception and encodes for 52 RR genes. Using in frame deletion mutants of each RR gene, we performed a systematic analysis of their role in V. cholerae biofilm formation. We determined that 7 RRs impacted expression of an essential biofilm gene and found that the recently characterized RR, VxrB, regulates expression of key structural and regulatory biofilm-genes in V...
June 12, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28607054/electron-shuttling-antibiotics-structure-bacterial-communities-by-modulating-cellular-levels-of-c-di-gmp
#16
Chinweike Okegbe, Blanche L Fields, Stephanie J Cole, Christopher Beierschmitt, Chase J Morgan, Alexa Price-Whelan, Richard C Stewart, Vincent T Lee, Lars E P Dietrich
Diverse organisms secrete redox-active antibiotics, which can be used as extracellular electron shuttles by resistant microbes. Shuttle-mediated metabolism can support survival when substrates are available not locally but rather at a distance. Such conditions arise in multicellular communities, where the formation of chemical gradients leads to resource limitation for cells at depth. In the pathogenic bacterium Pseudomonas aeruginosa PA14, antibiotics called phenazines act as oxidants to balance the intracellular redox state of cells in anoxic biofilm subzones...
June 12, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28607050/mouse-model-of-hematogenous-implant-related-staphylococcus-aureus-biofilm-infection-reveals-therapeutic-targets
#17
Yu Wang, Lily I Cheng, David R Helfer, Alyssa G Ashbaugh, Robert J Miller, Alexander J Tzomides, John M Thompson, Roger V Ortines, Andrew S Tsai, Haiyun Liu, Carly A Dillen, Nathan K Archer, Taylor S Cohen, Christine Tkaczyk, C Kendall Stover, Bret R Sellman, Lloyd S Miller
Infection is a major complication of implantable medical devices, which provide a scaffold for biofilm formation, thereby reducing susceptibility to antibiotics and complicating treatment. Hematogenous implant-related infections following bacteremia are particularly problematic because they can occur at any time in a previously stable implant. Herein, we developed a model of hematogenous infection in which an orthopedic titanium implant was surgically placed in the legs of mice followed 3 wk later by an i.v...
June 12, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28605597/bacterial-gtfb-augments-candida-albicans-accumulation-in-cross-kingdom-biofilms
#18
K Ellepola, Y Liu, T Cao, H Koo, C J Seneviratne
Streptococcus mutans is a biofilm-forming oral pathogen commonly associated with dental caries. Clinical studies have shown that S. mutans is often detected with Candida albicans in early childhood caries. Although the C. albicans presence has been shown to enhance bacterial accumulation in biofilms, the influence of S. mutans on fungal biology in this mixed-species relationship remains largely uncharacterized. Therefore, we aimed to investigate how the presence of S. mutans influences C. albicans biofilm development and coexistence...
June 1, 2017: Journal of Dental Research
https://www.readbyqxmd.com/read/28605431/matrix-exopolysaccharides-the-sticky-side-of-biofilm-formation
#19
Eve Maunders, Martin Welch
The Gram-negative pathogen Pseudomonas aeruginosa is found ubiquitously within the environment and is recognised as an opportunistic human pathogen that commonly infects burn wounds and immunocompromised individuals, or patients suffering from the autosomal recessive disorder cystic fibrosis (CF). During chronic infection, P. aeruginosa is thought to form structured aggregates known as biofilms characterised by a self-produced matrix which encases the bacteria, protecting them from anti-microbial attack and the host immune response...
June 12, 2017: FEMS Microbiology Letters
https://www.readbyqxmd.com/read/28605194/discovery-of-two-bacterial-nitric-oxide-responsive-proteins-and-their-roles-in-bacterial-biofilm-regulation
#20
Sajjad Hossain, Lisa-Marie Nisbett, Elizabeth M Boon
Bacterial biofilms form when bacteria adhere to a surface and produce an exopolysaccharide matrix ( Costerton Science 1999 , 284 , 1318 ; Davies Science 1998 , 280 , 295 ; Flemming Nat. Rev. Microbiol. 2010 , 8 , 623 ). Because biofilms are resistant to antibiotics, they are problematic in many aspects of human health and welfare, causing, for instance, persistent fouling of medical implants such as catheters and artificial joints ( Brunetto Chimia 2008 , 62 , 249 ). They are responsible for chronic infections in the lungs of cystic fibrosis patients and in open wounds, such as those associated with burns and diabetes...
June 12, 2017: Accounts of Chemical Research
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