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pathogenicity and biofilm formation

Bart J F Keijser, Tim J van den Broek, Dagmar E Slot, Lodewic van Twillert, Jolanda Kool, Clémentine Thabuis, Michel Ossendrijver, Fridus A van der Weijden, Roy C Montijn
Background: The oral cavity harbors a complex microbial ecosystem, intimately related to oral health and disease. The use of polyol-sweetened gum is believed to benefit oral health through stimulation of salivary flow and impacting oral pathogenic bacteria. Maltitol is often used as sweetener in food products. This study aimed to establish the in vivo effects of frequent consumption of maltitol-sweetened chewing gum on the dental plaque microbiota in healthy volunteers and to establish the cellular and molecular effects by in vitro cultivation and transcriptional analysis...
2018: Frontiers in Microbiology
Natalia Crespo Tapia, Heidy M W den Besten, Tjakko Abee
Listeria monocytogenes is a food-borne pathogen that can grow as a biofilm on surfaces. Biofilm formation in food-processing environments is a big concern for food safety, as it can cause product contamination through the food-processing line. Although motile aerobic bacteria have been described to form biofilms at the air-liquid interface of cell cultures, to our knowledge, this type of biofilm has not been described in L. monocytogenes before. In this study we report L. monocytogenes biofilm formation at the air-liquid interface of aerobically grown cultures, and that this phenotype is specifically induced when the media is supplemented with glycerol as a carbon and energy source...
March 15, 2018: International Journal of Food Microbiology
Graciela Rodríguez-Sevilla, Marta García-Coca, David Romera-García, John Jairo Aguilera-Correa, Ignacio Mahíllo-Fernández, Jaime Esteban, Concepción Pérez-Jorge
Lung disease in cystic fibrosis (CF) is characterized by the progressive colonization of the respiratory tract by different bacteria, which develop polymicrobial biofilms. In the past decades, there has been an increase in the number of CF patients infected with Non-Tuberculous Mycobacteria (NTM). Although Mycobacterium abscessus is the main NTM isolated globally, little is known about M. abscessus multispecies biofilm formation. In the present study we developed an in vitro model to study the phenotypic characteristics of biofilms formed by M...
March 6, 2018: International Journal of Medical Microbiology: IJMM
Michal M Dykas, Stuti K Desai, Abhijeet Patra, Mallikarjuna Rao Motapothula, Kingshuk Poddar, Linda J Kenney, Thirumalai Venkatesan
With the rise in nosocomial infections worldwide, research on materials with an intrinsic ability to inhibit biofilm formation has been generating a great deal of interest. In the present work, we describe how thin film material libraries generated by pulsed laser deposition can be used for simultaneously screening several novel metal oxide mixtures that inhibit biofilm formation in a common human pathogen, Salmonella enterica serovar Typhimurium. We discovered that in a material library constructed using two metal oxides, the net effect on biofilm formation can be modelled as an addition of the activities of the individual oxides weighted to their relative composition at that particular point on the library...
March 19, 2018: ACS Applied Materials & Interfaces
Alejandro Avilés-Reyes, Irlan Almeida Freires, Richard Besingi, Sangeetha Purushotham, Champion Deivanayagam, L Jeannine Brady, Jacqueline Abranches, José A Lemos
Protein glycosylation has been described as the most abundant and complex post-translational modification occurring in nature. Recent studies have enhanced our view of how this modification occurs in bacteria highlighting the role of protein glycosylation in various processes such as biofilm formation, virulence and host-microbe interactions. We recently showed that the collagen- and laminin-binding adhesin Cnm of the dental pathogen Streptococcus mutans is post-translationally modified by the PgfS glycosyltransferase...
March 16, 2018: Scientific Reports
José Andrés Medrano-Félix, Cristóbal Chaidez, Kristina D Mena, María Del Socorro Soto-Galindo, Nohelia Castro-Del Campo
Survival of bacterial pathogens in different environments is due, in part, to their ability to form biofilms. Four wild-type Salmonella enterica strains, two Oranienburg and two Saintpaul isolated from river water and animal feces, were tested for biofilm formation at the air-liquid interface under stressful conditions (pH and salinity treatments such as pH 3, NaCl 4.5 w/v; pH 7, NaCl 4.5 w/v; pH 10, NaCl 4.5 w/v; pH 3, Nacl 0.5 w/v; pH 7, NaCl 0.5 w/v; and pH 10, NaCl 0.5 w/v); Salmonella Typhimurium DT104 was used as a control strain...
March 15, 2018: Environmental Monitoring and Assessment
Olivier Poupel, Caroline Proux, Bernd Jagla, Tarek Msadek, Sarah Dubrac
The success of Staphylococcus aureus, as both a human and animal pathogen, stems from its ability to rapidly adapt to a wide spectrum of environmental conditions. Two-component systems (TCSs) play a crucial role in this process. Here, we describe a novel staphylococcal virulence factor, SpdC, an Abi-domain protein, involved in signal sensing and/or transduction. We have uncovered a functional link between the WalKR essential TCS and the SpdC Abi membrane protein. Expression of spdC is positively regulated by the WalKR system and, in turn, SpdC negatively controls WalKR regulon genes, effectively constituting a negative feedback loop...
March 2018: PLoS Pathogens
Quintin Borgersen, David T Bolick, Glynis L Kolling, Matthew Aijuka, Fernando Ruiz-Perez, Richard L Guerrant, James P Nataro, Araceli E Santiago
Enteroaggregative E. coli (EAEC) is associated with food-borne outbreaks of diarrhea and growth faltering among children in developing countries. A Shiga toxin-producing EAEC strain of serotype O104:H4 strain caused one of the largest outbreaks of a food-borne infection in Europe in 2011. The outbreak was traced to contaminated fenugreek sprouts, yet the mechanisms whereby such persistent contamination of sprouts could have occurred are not clear. We found that under ambient conditions of temperature and in minimal media, pathogenic Shiga toxin-producing EAEC O104:H4 227-11 and non-Shiga toxin-producing 042 strains both produce high levels of exopolysaccharide structures (EPS) that are released to the external milieu...
March 15, 2018: Gut Microbes
Brijesh Kumar, John L Sorensen, Silvia T Cardona
Burkholderia cenocepacia is an opportunistic bacterium that can thrive in different environments, including the amino acid-rich mucus of the cystic fibrosis (CF) lung. B. cenocepacia responds to the nutritional conditions that mimic the CF sputum by increasing flagellin expression and swimming motility. Individual amino acids also induce swimming but not flagellin expression. Here, we show that modulation of the second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) levels by the PAS-containing c-di-GMP phosphodiesterase, BCAL1069 (CdpA), regulates the swimming motility of B...
2018: Frontiers in Cellular and Infection Microbiology
Arwa Abu Khweek, Amal O Amer
Legionella pneumophila ( L. pneumophila ) is an opportunistic waterborne pathogen and the causative agent for Legionnaires' disease, which is transmitted to humans via inhalation of contaminated water droplets. The bacterium is able to colonize a variety of man-made water systems such as cooling towers, spas, and dental lines and is widely distributed in multiple niches, including several species of protozoa In addition to survival in planktonic phase, L. pneumophila is able to survive and persist within multi-species biofilms that cover surfaces within water systems...
2018: Frontiers in Cellular and Infection Microbiology
Yu Cao, Hualiang Pi, Pete Chandrangsu, Yongtao Li, Yuqi Wang, Han Zhou, Hanqin Xiong, John D Helmann, Yanfei Cai
Plant growth promoting rhizobacteria (PGPR) provide an effective and environmentally sustainable method to protect crops against pathogens. The spore-forming Bacilli are attractive PGPR due to their ease of storage and application. Here, we characterized two rhizosphere-associated Bacillus velezensis isolates (Y6 and F7) that possess strong antagonistic activity against Ralstonia solanacearum and Fusarium oxysporum under both laboratory and greenhouse conditions. We identified three lipopeptide (LP) compounds (surfactin, iturin and fengycin) as responsible for the antimicrobial activity of these two strains...
March 12, 2018: Scientific Reports
Jobina Rajkumari, Subhomoi Borkotoky, Ayaluru Murali, Kitlangki Suchiang, Saswat Kumar Mohanty, Siddhardha Busi
The production of virulence determinants and biofilm formation in numerous pathogens is regulated by the cell-density-dependent phenomenon, Quorum sensing (QS). The QS system in multidrug resistant opportunistic pathogen, P. aeruginosa constitutes of three main regulatory circuits namely Las, Rhl, and Pqs which are closely linked to its pathogenicity and establishment of chronic infections. In spite intensive antibiotic therapy, P. aeruginosa continue to be an important cause of nosocomial infections and also the major cause of mortality in Cystic Fibrosis patients with 80% of the adults suffering from chronic P...
March 8, 2018: Microbial Pathogenesis
Govindan Rajivgandhi, Ramachandran Vijayan, Muthuchamy Maruthupandy, Baskaralingam Vaseeharan, Natesan Manoharan
Urinary tract infections (UTIs) are a diverse public health complication and are caused by range of pathogens, however most often by Gram negative bacteria which cause significant life threatening risks to different populations. The prevalence rate and antimicrobial resistance among the Gram negative uropathogens alarmed to significantly heighten the economic burden of these infections. In this study, we investigated the role of Pyrrolo[1,2-a] pyrazine-1,4-dione,hexahydro-3-(2-methylpropyl) on endophytic actinomycetes Nocardiopsis sp...
March 7, 2018: Microbial Pathogenesis
Manmohit Kalia, Vivek Kumar Yadav, Pradeep Kumar Singh, Deepmala Sharma, Shahid Suhail Narvi, Vishnu Agarwal
AIMS: Pseudomonas aeruginosa is a well-known pathogen responsible for various infections due to its capability to develop biofilm and various virulent phenotypes that are regulated by quorum sensing. Pathogenesis of the bacteria may be halted by interfering with the signaling molecules and the quorum sensing receptors. Therefore, the present study explores the potential of parthenolide, a sesquiterpene lactone of feverfew plant, as a promising candidate against P. aeruginosa PAO1 associated virulence factors and biofilm...
March 7, 2018: Life Sciences
Alejandro Avilés-Reyes, Irlan Almeida Freires, Jessica K Kajfasz, Dicler Barbieri, James H Miller, José A Lemos, Jacqueline Abranches
We report the whole genome sequence (WGS) of the serotype e Cbm+ strain LAR01 of Streptococcus mutans, a dental pathogen frequently associated with extra-oral infections. The LAR01 genome is a single circular chromosome of 2.1 Mb with a GC content of 36.96%. The genome contains 15 PTS gene clusters, 7 cell wall-anchored (LPxTG) proteins, all genes required for the development of natural competence and genes coding for mutacins VI and K8. Interestingly, the cbm gene is genetically linked to a putative type VII secretion system that has been found in Mycobacteria and few other gram-positive bacteria...
March 9, 2018: Molecular Oral Microbiology
Michael Hornsey, David W Wareham
Multidrug-resistant lineages of Acinetobacter baumannii (MDRAB) are important nosocomial pathogens. As tigecycline remains active against most MDRAB we sought to investigate whether tigecycline resistance impacts biological fitness. The effects of treatment-emergent tigecycline resistance were investigated in vitro and in vivo using two pre- (AB210; W6976) and post-therapy (AB211; W7282) clinical pairs, recovered from individual patients, where tigecycline resistance was associated with up-regulated efflux activity...
March 9, 2018: Scientific Reports
Helma Wennemers, Carlotta Foletti, Rolf Kramer, Harald Mauser, Urs Jenal, Konrad Bleicher
c di GMP is an attractive target in the fight against bacterial infections as it is a near ubiquitous second messenger that regulates important cellular processes, including biofilm formation and virulence of pathogens. The screening of a combinatorial peptide library enabled the identification of the proline-rich tetrapeptide Gup-Gup-Nap-Arg that binds c di GMP in water with selectivity over other nucleotides. Computational and CD spectroscopic studies provided a binding mode of the complex and enabled the design of a pentapeptide with even higher binding strength towards c di GMP...
March 9, 2018: Angewandte Chemie
Hua Qi, Baosheng Li, Heling Wang, Qing Cai, Xu Quan, Yunxia Cui, Weiyan Meng
BACKGROUND: When presented with a surface or an interface, bacteria often grow as biofilms in which cells are held together by an extracellular matrix. Biofilm formation on implants is an initiating factor for their failure. Porphyromonas gingivalis is the primary etiologic bacteria of initiation and progression of periodontal disease. This microorganism is also the risk factor of many systemic diseases, such as cardiovascular disease, diabetes, and pulmonary infection. To date, no medication that can remove such biofilm has been accepted for clinical use...
March 2018: Journal of Periodontology
Roeland L Berendsen, Gilles Vismans, Ke Yu, Yang Song, Ronnie de Jonge, Wilco P Burgman, Mette Burmølle, Jakob Herschend, Peter A H M Bakker, Corné M J Pieterse
Disease suppressive soils typically develop after a disease outbreak due to the subsequent assembly of protective microbiota in the rhizosphere. The role of the plant immune system in the assemblage of a protective rhizosphere microbiome is largely unknown. In this study, we demonstrate that Arabidopsis thaliana specifically promotes three bacterial species in the rhizosphere upon foliar defense activation by the downy mildew pathogen Hyaloperonospora arabidopsidis. The promoted bacteria were isolated and found to interact synergistically in biofilm formation in vitro...
March 8, 2018: ISME Journal
Siphathele Sibanda, Stanford Kwenda, Collins K Tanui, Divine Y Shyntum, Teresa A Coutinho, Lucy N Moleleki
Pantoea ananatis LMG 2665T synthesizes and utilizes acyl homoserine lactones (AHLs) for signalling. The complete set of genes regulated by the EanI/R quorum sensing (QS) system in this strain is still not fully known. In this study, RNA-sequencing (RNA-seq) was used to identify the EanI/R regulon in LMG 2665T . Pairwise comparisons of LMG 2665T in the absence of AHLs (Optical density (OD)600 = 0.2) and in the presence of AHLs (OD600 = 0.5) were performed. Additionally, pairwise comparisons of LMG 2665T and its QS mutant at OD600 = 0...
March 7, 2018: Genes
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