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virulence genes and biofilm formation

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https://www.readbyqxmd.com/read/28325850/phenotypic-diversity-and-genotypic-flexibility-of-burkholderia-cenocepacia-during-long-term-chronic-infection-of-cystic-fibrosis-lungs
#1
Amy Huei-Yi Lee, Stephane Flibotte, Sunita Sinha, Adrianna Paiero, Rachel L Ehrlich, Sergey Balashov, Garth D Ehrlich, James E A Zlosnik, Joshua Chang Mell, Corey Nislow
Chronic bacterial infections of the lung are the leading cause of morbidity and mortality in cystic fibrosis patients. Tracking bacterial evolution during chronic infections can provide insights into how host selection pressures-including immune responses and therapeutic interventions-shape bacterial genomes. We carried out genomic and phenotypic analyses of 215 serially collected Burkholderia cenocepacia isolates from 16 cystic fibrosis patients, spanning a period of 2-20 yr and a broad range of epidemic lineages...
March 21, 2017: Genome Research
https://www.readbyqxmd.com/read/28320949/discovery-of-scmr-as-a-global-regulator-of-secondary-metabolism-and-virulence-in-burkholderia-thailandensis-e264
#2
Dainan Mao, Leah B Bushin, Kyuho Moon, Yihan Wu, Mohammad R Seyedsayamdost
Bacteria produce a diverse array of secondary metabolites that have been invaluable in the clinic and in research. These metabolites are synthesized by dedicated biosynthetic gene clusters (BGCs), which assemble architecturally complex molecules from simple building blocks. The majority of BGCs in a given bacterium are not expressed under normal laboratory growth conditions, and our understanding of how they are silenced is in its infancy. Here, we have addressed this question in the Gram-negative model bacterium Burkholderia thailandensis E264 using genetic, transcriptomic, metabolomic, and chemical approaches...
March 20, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28289081/light-modulates-metabolic-pathways-and-other-novel-physiological-traits-in-the-human-pathogen-acinetobacter-baumannii
#3
Gabriela L Müller, Marisel Tuttobene, Matías Altilio, Maitena Martinez Amezaga, Meaghan Nguyen, P Pamela Cribb, Larisa E Cybulski, María Soledad Ramírez, Silvia Altabe, María Alejandra Mussi
Light sensing in chemotrophic bacteria has been relatively recently ascertained. In the human pathogen Acinetobacter baumannii, light modulates motility, biofilm formation and virulence through the BLUF photoreceptor BlsA. In addition, light can induce reduction in susceptibility to certain antibiotics such as minocycline and tigecycline in a photoreceptor-independent manner. In this work we identified new traits whose expression are modulated by light in this pathogen, which comprise not only important determinants related to pathogenicity and antibiotic resistance, but also metabolic pathways, which represents a novel concept for chemotrophic bacteria...
March 13, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28283006/-investigation-of-biofilm-formation-properties-of-staphylococcus-isolates
#4
Duygu Nilüfer Öcal, İştar Dolapçı, Zeynep Ceren Karahan, Alper Tekeli
Biofilm production is an important virulence factor which allows staphylococci to adhere to medical devices. The principal component of biofilm is a "polysaccharide intercellular adhesin (PIA)" which is composed of a beta-1,6-N-acetylglucosamine polymer synthesized by an enzyme (N-acetylglucosamine transferase) encoded by the ica operon found on the bacterial chromosome. This operon is composed of four genes (A, B, C, and D), and a transposable element IS256. In this study, we aimed to determine the biofilm production characteristics of invasive/non-invasive staphylococcus isolates and different staphylococcus species...
January 2017: Mikrobiyoloji Bülteni
https://www.readbyqxmd.com/read/28280492/mitochondrial-complex-v-%C3%AE-subunit-is-critical-for-candida-albicans-pathogenicity-through-modulating-multiple-virulence-properties
#5
Shui-Xiu Li, Yan-Jun Song, Yi-Shan Zhang, Hao-Tian Wu, Hui Guo, Kun-Ju Zhu, Dong-Mei Li, Hong Zhang
The α subunit (ATP1) is a vital component of mitochondrial complex V which counts for the majority of cellular ATP production in a living organism. Nevertheless, how the α subunit influences other cellular processes such as pathogenicity in Candida albicans remains poorly understood. To address this question, ATP1 mutant (atp1Δ/Δ) and the gene-reconstituted strain (atp1Δ/ATP1) have been constructed in this study and their pathogenicity-related traits are compared to those of wild type (WT). In a murine model of disseminated candidiasis, atp1Δ/Δ infected mice have a significantly higher survival rate and experience a lower fungal burden in tissues...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28278272/additional-regulatory-activities-of-mrkh-for-the-transcriptional-expression-of-the-klebsiella-pneumoniae-mrk-genes-antagonist-of-h-ns-and-repressor
#6
Miguel A Ares, José L Fernández-Vázquez, Sabino Pacheco, Verónica I Martínez-Santos, Ma Dolores Jarillo-Quijada, Javier Torres, María D Alcántar-Curiel, Jorge A González-Y-Merchand, Miguel A De la Cruz
Klebsiella pneumoniae is a common opportunistic pathogen causing nosocomial infections. One of the main virulence determinants of K. pneumoniae is the type 3 pilus (T3P). T3P helps the bacterial interaction to both abiotic and biotic surfaces and it is crucial for the biofilm formation. T3P is genetically organized in three transcriptional units: the mrkABCDF polycistronic operon, the mrkHI bicistronic operon and the mrkJ gene. MrkH is a regulatory protein encoded in the mrkHI operon, which positively regulates the mrkA pilin gene and its own expression...
2017: PloS One
https://www.readbyqxmd.com/read/28270274/crispr-cas-system-presents-multiple-transcriptional-units-including-antisense-rnas-that-are-expressed-in-minimal-medium-and-upregulated-by-ph-in-salmonella-enterica-serovar-typhi
#7
Liliana Medina-Aparicio, Javier E Rebollar-Flores, América A Beltrán-Luviano, Alejandra Vázquez, Rosa M Gutiérrez-Ríos, Leticia Olvera, Edmundo Calva, Ismael Hernández-Lucas
The CRISPR-Cas system is involved in bacterial immunity, virulence, gene regulation, biofilm formation and sporulation. In Salmonella enterica serovar Typhi, this system consists of five transcriptional units including antisense RNAs. It was determined that these genetic elements are expressed in minimal medium and are up-regulated by pH. In addition, a transcriptional characterization of cas3 and ascse2-1 is included herein.
February 2017: Microbiology
https://www.readbyqxmd.com/read/28261183/effect-of-quorum-quenching-lactonase-in-clinical-isolates-of-pseudomonas-aeruginosa-and-comparison-with-quorum-sensing-inhibitors
#8
Assia Guendouze, Laure Plener, Janek Bzdrenga, Pauline Jacquet, Benjamin Rémy, Mikael Elias, Jean-Philippe Lavigne, David Daudé, Eric Chabrière
Pseudomonas aeruginosa is a Gram negative pathogenic bacterium involved in many human infections including otitis, keratitis, pneumonia, and diabetic foot ulcers. P. aeruginosa uses a communication system, referred to as quorum sensing (QS), to adopt a group behavior by synchronizing the expression of certain genes. Among the regulated traits, secretion of proteases or siderophores, motility and biofilm formation are mainly involved in the pathogenicity. Many efforts have been dedicated to the development of quorum sensing inhibitors (QSI) and quorum quenching (QQ) agents to disrupt QS...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28255686/reducing-virulence-and-biofilm-of-pseudomonas-aeruginosa-by-potential-quorum-sensing-inhibitor-carotenoid-zeaxanthin
#9
Barış Gökalsın, Busecan Aksoydan, Burak Erman, Nüzhet Cenk Sesal
Pseudomonas aeruginosa can regulate its virulence gene expressions by using a signal system called quorum sensing. It is known that inhibition of quorum sensing can block biofilm formation and leave the bacteria defenseless. Therefore, it is necessary to determine natural sources to obtain potential quorum sensing inhibitors. This study aims to investigate an alternative treatment approach by utilizing the carotenoid zeaxanthin to reduce the expressions of P. aeruginosa virulence factors through quorum sensing inhibition...
March 2, 2017: Microbial Ecology
https://www.readbyqxmd.com/read/28251783/indole-signaling-and-micro-algal-auxins-decrease-the-virulence-of-vibrio-campbellii-a-major-pathogen-of-aquatic-organisms
#10
Qian Yang, Gde Sasmita Julyantoro Pande, Zheng Wang, Baochuan Lin, Robert A Rubin, Gary J Vora, Tom Defoirdt
Vibrios belonging to the Harveyi clade are major pathogens of marine vertebrates and invertebrates, causing major losses in wild and cultured organisms. Despite their significant impact, the pathogenicity mechanisms of these bacteria are not yet completely understood. In this study, we investigated the impact of indole signaling on the virulence of Vibrio campbellii. Elevated indole levels significantly decreased motility, biofilm formation, exopolysaccharide production and virulence to crustacean hosts. Indole furthermore inhibited the three-channel quorum sensing system of V...
March 2, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28246361/new-mouse-model-for-chronic-infections-by-gram-negative-bacteria-enabling-the-study-of-anti-infective-efficacy-and-host-microbe-interactions
#11
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
https://www.readbyqxmd.com/read/28236620/influence-of-huang-lian-jie-du-decoction-on-quorum-sensing-system-of-pseudomonas-aeruginosa
#12
Fei Xia, Lihua Ye, Ping Wang, Mingwei Zhang
Context • Pseudomonas aeruginosa (P aeruginosa) is an opportunistic and nosocomial, Gram-negative pathogen that is characteristic of quorum sensing (QS) modulation. QS inhibition (QSI) is considered to be a new approach to antimicrobial treatment that may reduce issues of antibiotic resistance. Traditional Chinese herbs have been recognized as a source of QSI. Objective • This study was intended to investigate whether the Huang Lian Jie Du decoction (HLJJD) possesses the ability to produce anti-QS activity...
February 27, 2017: Alternative Therapies in Health and Medicine
https://www.readbyqxmd.com/read/28223377/exopolysaccharide-repressing-small-molecules-with-antibiofilm-and-antivirulence-activity-against-pseudomonas-aeruginosa
#13
Erik van Tilburg Bernardes, Laetitia Charron-Mazenod, David J Reading, Shauna L Reckseidler-Zenteno, Shawn Lewenza
Biofilm formation is a universal virulence strategy in which bacteria grow in dense microbial communities enmeshed within a polymeric extracellular matrix that protects them from antibiotic exposure and the immune system. Pseudomonas aeruginosa is an archetypal biofilm-forming organism that utilizes a biofilm growth strategy to cause chronic lung infections in Cystic Fibrosis (CF) patients. The extracellular matrix of P. aeruginosa biofilms is comprised mainly of exopolysaccharides (EPS) and DNA. Both mucoid and non-mucoid isolates of P...
February 21, 2017: Antimicrobial Agents and Chemotherapy
https://www.readbyqxmd.com/read/28217123/virulence-markers-and-phylogenetic-analysis-of-escherichia-coli-strains-with-hybrid-eaec-upec-genotypes-recovered-from-sporadic-cases-of-extraintestinal-infections
#14
Flaviane B M Lara, Danielly R Nery, Pâmela M de Oliveira, Mayana L Araujo, Fabiana R Q Carvalho, Lorena C F Messias-Silva, Leonardo B Ferreira, Celio Faria-Junior, Alex L Pereira
Virulence genes from different E. coli pathotypes are blended in hybrid strains. E. coli strains with hybrid enteroaggregative/uropathogenic (EAEC/UPEC) genotypes have sporadically emerged causing outbreaks of extraintestinal infections, however their association with routine infections is yet underappreciated. We assessed 258 isolates of E. coli recovered from 86 consecutive cases of extraintestinal infections seeking EAEC and hybrid genotype (EAEC/UPEC) strains. Extensive virulence genotyping was carried out to detect 21 virulence genes, including molecular predictors of EAEC and UPEC strains...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28216386/serotonin-disturbs-colon-epithelial-tolerance-of-commensal-e-coli-by-increasing-nox2-derived-superoxide
#15
Suhrid Banskota, Sushil Chandra Regmi, Jaya Gautam, Pallavi Gurung, Yu-Jeong Lee, Sae Kwang Ku, Jin-Hyung Lee, Jintae Lee, Hyeun Wook Chang, Sang Joon Park, Jung-Ae Kim
Adherent-invasive E. coli colonization and Toll-like receptor (TLR) expression are increased in the gut of inflammatory bowel disease (IBD) patients. However, the underlying mechanism of such changes has not been determined. In the current study, it was examined whether gut serotonin (5-hydroxytryptamine, 5-HT) can induce adherent-invasive E. coli colonization and increase TLR expression. In a co-culture system, commensal E. coli strain (BW25113, BW) adhered minimally to colon epithelial cells, but this was significantly enhanced by 5-HT to the level of a pathogenic strain (EDL933)...
February 17, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28214190/biofilm-formation-by-staphylococcus-aureus-isolates-from-a-dental-clinic-in-konya-turkey
#16
Emrah Torlak, Emre Korkut, Ali T Uncu, Yağmur Şener
The ability of Staphylococcus aureus to form biofilm is considered to be a major virulence factor influencing its survival and persistence in both the environment and the host. Biofilm formation in S. aureus is most frequently associated with production of polysaccharide intercellular adhesion by ica operon-encoded enzymes. The present work aimed at evaluating the in vitro biofilm production and presence of the icaA and icaD genes in S. aureus isolates from a dental clinic in Konya, Turkey. The surfaces of inanimate objects were sampled over a period of six months...
February 14, 2017: Journal of Infection and Public Health
https://www.readbyqxmd.com/read/28197135/cloning-and-characterization-of-the-autoinducer-synthase-gene-from-lipid-degrading-bacterium-cedecea-neteri
#17
Kian-Hin Tan, Kah-Yan How, Jia-Yi Tan, Wai-Fong Yin, Kok-Gan Chan
The process of intercellular communication among bacteria, termed quorum sensing (QS), is mediated by small diffusible molecules known as the autoinducers. QS allows the population to react to the change of cell density in unison, in processes such as biofilm formation, plasmid conjugation, virulence, motility and root nodulation. In Gram-negative proteobacteria, N-acyl homoserine lactone (AHL) is the common "language" to coordinate gene expression. This signaling molecule is usually synthesized by LuxI-type proteins...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28188589/synergistic-activity-of-sub-inhibitory-concentrations-of-curcumin-with-ceftazidime-and-ciprofloxacin-against-pseudomonas-aeruginosa-quorum-sensing-related-genes-and-virulence-traits
#18
Shekoufeh Roudashti, Habib Zeighami, Hesam Mirshahabi, Shahin Bahari, Ali Soltani, Fakhri Haghi
Quorum sensing (QS) system in Pseudomonas aeruginosa may be an important target for pharmacological intervention. The present study aimed to investigate the synergetic activity of sub-MIC concentrations of curcumin (C) with ceftazidime (CAZ) and ciprofloxacin (CIP) against P. aeroginusa QS system. We determined the MIC and synergistic activity of C, CAZ and CIP against P. aeroginusa PAO1 using broth microdilution and checkerboard titration methods. The activity of sub-MIC (1/4 and 1/16 MIC) concentrations of C on the QS signal molecules was assessed using a reporter strain assay...
March 2017: World Journal of Microbiology & Biotechnology
https://www.readbyqxmd.com/read/28173753/conjugative-type-ivb-pilus-recognizes-lipopolysaccharide-of-recipient-cells-to-initiate-papi-1-pathogenicity-island-transfer-in-pseudomonas-aeruginosa
#19
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
https://www.readbyqxmd.com/read/28167518/pleiotropic-regulation-of-virulence-genes-in-streptococcus-mutans-by-a-conserved-small-protein-sprv
#20
Manoharan Shankar, Mohammad S Hossain, Indranil Biswas
Streptococcus mutans, an oral pathogen associated with dental caries, colonizes tooth surfaces as polymicrobial biofilms, known as dental plaque. S. mutans expresses several virulence factors that allow the organism to tolerate environmental fluctuations and to compete with other microorganisms. We recently identified that a small hypothetical protein (90 amino acids) was essential for normal growth of the bacterium. Inactivation of the gene SMU.2137 encoding this protein caused a significant growth defect and loss of various virulence-associated functions...
February 6, 2017: Journal of Bacteriology
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