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level of biofilm formation

Zulfiqar Ali Mirani, Muhammad Naseem Khan, Anila Siddiqui, Fouzia Khan, Mubashir Aziz, Shagufta Naz, Ayaz Ahmed, Seema Ismat Khan
Objectives: Staphylococcus aureus is a Gram-positive pathogen, well known for its resistance and versatile lifestyle. Under unfavourable conditions, it adapts biofilm mode of growth. For staphylococcal biofilm formation, production of extracellular polymeric substances (EPS) is a pre-requisite, which is regulated by ica operon-encoded enzymes. This study was designed to know the impact of ascorbic acid on biofilm formation and colony spreading processes of S. aureus and MRSA. Materials and Methods: The isolates of methicillin-resistant S...
February 2018: Iranian Journal of Basic Medical Sciences
Niluni M Wijesundara, H P Vasantha Rupasinghe
In the present study, essential oils (EOs) extracted from oregano, sage, cloves, and ginger were evaluated for the phytochemical profile, antibacterial, and anti-biofilm activities against Streptococcus pyogenes. The broth microdilution method was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of EOs. The minimum biofilm inhibitory concentrations (MBICs) were determined using MTT assay and fixed biofilms were observed through scan electron microscopy...
February 13, 2018: Microbial Pathogenesis
Jun Myoung Yu, Dongping Wang, Tessa R Ries, Leland S Pierson, Elizabeth A Pierson
Phenazines are bacterial secondary metabolites and play important roles in the antagonistic activity of the biological control strain P. chlororaphis 30-84 against take-all disease of wheat. The expression of the P. chlororaphis 30-84 phenazine biosynthetic operon (phzXYFABCD) is dependent on the PhzR/PhzI quorum sensing system located immediately upstream of the biosynthetic operon as well as other regulatory systems including Gac/Rsm. Bioinformatic analysis of the sequence between the divergently oriented phzR and phzX promoters identified features within the 5'-untranslated region (5'-UTR) of phzX that are conserved only among 2OHPCA producing Pseudomonas...
2018: PloS One
Barbara Hofbauer, Jan Vomacka, Matthias Stahl, Vadim S Korotkov, Megan C Jennings, William Wuest, Stephan A Sieber
Staphylococcus aureus is a major bacterial pathogen that invades and damages host tissue by the expression of devastating toxins. We here performed a phenotypic screen of 35 molecules that were structurally inspired by previous hydroxyamide-based S. aureus virulence inhibitors compiled from commercial sources or designed and synthesized de novo. One of the most potent compounds, AV73, did not only reduce hemolytic alpha-hemolysin production in S. aureus but also impeded in vitro biofilm formation. The effect of AV73 on bacterial proteomes and extracellular protein levels were analyzed by quantitative proteomics and revealed a significant down-regulation of major virulence and biofilm promoting proteins...
February 16, 2018: Biochemistry
Fangchao Song, Hao Wang, Karin Sauer, Dacheng Ren
Recently, we reported that the stiffness of poly(dimethylsiloxane) (PDMS) affects the attachment of Pseudomonas aeruginosa , and the morphology and antibiotic susceptibility of attached cells. To further understand how P. aeruginosa responses to material stiffness during attachment, the wild-type P. aeruginosa PAO1 and several isogenic mutants were characterized for their attachment on soft and stiff PDMS. Compared to the wild-type strain, mutation of the oprF gene abolished the differences in attachment, growth, and size of attached cells between soft and stiff PDMS surfaces...
2018: Frontiers in Microbiology
Karsten Zecher, Vishwa Prasad Aitha, Kirsten Heuer, Herbert Ahlers, Katrin Roland, Michael Fiedel, Bodo Philipp
Marine biofouling on artificial surfaces such as ship hulls or fish farming nets causes enormous economic damage. The time for the developmental process of antifouling coatings can be shortened by reliable laboratory assays. For designing such test systems, it is important that toxic effects can be excluded, that multiple parameters can be addressed simultaneously and that mechanistic aspects can be included. In this study, a multi-step approach for testing antifouling coatings was established employing photoautotrophic biofilm formation of marine microorganisms in micro- and mesoscoms...
February 10, 2018: Journal of Microbiological Methods
Tian-Nyu Wang, Anna H Kaksonen, Pei-Ying Hong
AIM: This study evaluated two methods, namely high performance liquid chromatography with fluorescence detection (HPLC-FLD) and Vibrio harveyi BB170 bioassay, for autoinducer-2 (AI-2) quantification in marine samples. Using both methods, the study also investigated the stability of AI-2 in varying pH, temperature and media, as well as quantified the amount of AI-2 signals in marine samples. METHODS AND RESULTS: HPLC-FLD method showed a higher level of reproducibility and precision compared to V...
February 11, 2018: Journal of Applied Microbiology
Monica Feng, Andrew C Schaff, Sara A Cuadra Aruguete, Hailey E Riggs, Steven L Distelhorst, Mitchell F Balish
Mycoplasma pneumoniae is a bacterial pathogen of humans that is a major causative agent of chronic respiratory disease. M. pneumoniae infections often recur even after successful treatment of symptoms with antibiotics, and resistance to antibiotics is increasing worldwide, with nearly complete resistance in some places. Although biofilms often contribute to chronicity and resistance, M. pneumoniae biofilms remain poorly characterized. Scanning electron microscopy revealed that cells of wild-type (WT) M. pneumoniae strain M129 biofilms, as well as mutants II-3 and II-3R, in vitro became increasingly rounded as the biofilm towers matured over 5 days...
February 7, 2018: International Journal of Medical Microbiology: IJMM
Alexandre Lamas, Patricia Regal, Beatriz Vázquez, José M Miranda, Alberto Cepeda, Carlos M Franco
It takes several steps to bring food from the farm to the fork (dining table), and contamination with food-borne pathogens can occur at any point in the process. Campylobacter spp. and Salmonella spp. are the main microorganisms responsible for foodborne disease in the European Union. These two pathogens are able to persist throughout the food supply chain thanks to their ability to form biofilms. Owing to the high prevalence of Salmonella and especially of Campylobacter in the food supply chain and the huge efforts of food authorities to reduce these levels, it is of great importance to fully understand their mechanisms of persistence...
February 9, 2018: Journal of the Science of Food and Agriculture
Leila Asadpour
OBJECTIVES: Pseudomonas aeruginosa is frequent in infectious diseases, such as burn and wound infections, making it one of the most promising opportunistic pathogens. The aim of this study was to investigate the antibiotic resistance, biofilm production capacity, and the frequency of genes, which are effective in the biofilm formation and virulence of Pseudomonas aeruginosa, from burn infections. METHODS: In this study, resistance of 90 P. aeruginosa strains to twelve antibacterial agents and extended-spectrum beta-lactamases (ESBLs) and Metallo-β-lactamases(MBL) enzymes production were phenotypically assessed according to Clinical & Laboratory Standards Institute guidelines...
February 5, 2018: Journal of Global Antimicrobial Resistance
H Z Neihaya, H H Zaman
Silver nanoparticles showed enhanced biofilm inhibitory activity of clinical pathogens. Eleven isolates (45.8%) of E. coli bacteria were obtained from 24 wound specimens. Silver nanoparticles biosynthesized by E. coli culture supernatant with exhibition dark brown color after 24 hr of incubation. Scanning electron microscopy showed that Ag-NPs spherical particles and its size were (14.2-67.8) nm and its average was 33.6 nm. X-ray diffraction shows one high peak at 2ø (32.5°) compared with standard data...
January 31, 2018: Microbial Pathogenesis
C Gökmenoglu, N B Kara, M Beldüz, A Kamburoğlu, I Tosun, E Sadik, C Kara
AIMS: Candida albicans adhesion to any oral substrata is the first and essential stage in forming a pathogenic fungal biofilm. In general, yeast cells have remarkable potential to adhere to host surfaces, such as teeth or mucosa, and to artificial, non-biological surfaces, such as dental materials. C. albicans adhesion to denture materials is widely recognized as the main reason for the development of stomatitis. This study compared the susceptibility of different parts of the implant system with C...
January 2018: Nigerian Journal of Clinical Practice
Nileshkumar Dubey, Kassapa Ellepola, Fanny E D Decroix, Julien L P Morin, A H Castro Neto, Chaminda J Seneviratne, Vinicius Rosa
The time needed for the osseointegration of titanium implants is deemed too long. Moreover, the bacterial colonization of their surfaces is a major cause of failure. Graphene can overcome these issues but its wet transfer onto substrates employs hazardous chemicals limiting the clinical applications. Alternatively, dry transfer technique has been developed, but the biological properties of this technique remain unexplored. Here, a dry transfer technique based on a hot-pressing method allowed to coat titanium substrates with high-quality graphene and coverage area >90% with a single transfer...
February 6, 2018: Nanotoxicology
Deping Tang, Qiyu Gao, Yang Zhao, Yang Li, Peng Chen, Jianping Zhou, Ruixiang Xu, Zhengrong Wu, Yuandong Xu, Hongyu Li
Bioleaching is a promising process for 350 million tons Jinchuan low grade pentlandite. But high concentration of Mg2+ is harmful to bioleaching microorganisms. Interestingly, biofilm formation can improve leaching rate. Thus, it is actual necessary to investigate the effect of Mg2+ stress on Acidithiobacillus ferrooxidans biofilms formatiom. In this study, we found that 0.1 and 0.5M Mg2+ stress significantly reduced the total biomass of biofilm in a dose-dependent manner. The observation results of EPS and bacteria using Confocal Laser Scanning Microscopy showed the biofilm became thinner and looser under Mg2+ stress...
February 2, 2018: FEMS Microbiology Letters
James Paul Hovis, Ryan Montalvo, Dimitrius Marinos, Manjari Joshi, Mark Shirtliff, Theodore T Manson, Robert V O'Toole
OBJECTIVES: To evaluate the effectiveness of intraoperative vancomycin powder in prevention of surgical site infection and biofilm formation on implants in a contaminated animal fixation model. METHODS: We created a rabbit surgical model including fixation implants at a tibial surgical site seeded with methicillin-resistant Staphylococcus aureus. Our study cohort included 18 rabbits. Nine received vancomycin powder at the surgical site, and the other 9 did not. Serum vancomycin levels were measured at scheduled time points over 24 hours...
January 30, 2018: Journal of Orthopaedic Trauma
Shinya Sugimoto, Fumiya Sato, Reina Miyakawa, Akio Chiba, Shoichi Onodera, Seiji Hori, Yoshimitsu Mizunoe
Staphylococcus aureus is a major causative agent for biofilm-associated infections. Inside biofilms, S. aureus cells are embedded in an extracellular matrix (ECM) composed of polysaccharide-intercellular adhesins (PIA), proteins, and/or extracellular DNA (eDNA). However, the importance of each component and the relationship among them in biofilms of diverse strains are largely unclear. Here, we characterised biofilms formed by 47 S. aureus clinical isolates. In most (42/47) of the strains, biofilm formation was augmented by glucose supplementation...
February 2, 2018: Scientific Reports
Candela Muriel, Eva Arrebola, Miguel Redondo-Nieto, Francisco Martínez-Granero, Blanca Jalvo, Sebastian Pfeilmeier, Esther Blanco-Romero, Irene Baena, Jacob G Malone, Rafael Rivilla, Marta Martín
The transcriptional regulator AmrZ is a global regulatory protein conserved within the pseudomonads. AmrZ can act both as a positive and a negative regulator of gene expression, controlling many genes implicated in environmental adaption. Regulated traits include motility, iron homeostasis, exopolysaccharides production and the ability to form biofilms. In Pseudomonas fluorescens F113, an amrZ mutant presents a pleiotropic phenotype, showing increased swimming motility, decreased biofilm formation and very limited ability for competitive colonization of rhizosphere, its natural habitat...
January 31, 2018: Scientific Reports
Roberto E Bruna, María Victoria Molino, Martina Lazzaro, Javier F Mariscotti, Eleonora García Véscovi
PrtA is the major secreted metalloprotease of Serratia marcescens. Previous reports implicate PrtA in the pathogenic capacity of this bacteria. PrtA is also clinically used as a potent analgesic and anti-inflammatory drug and its catalytic properties attract industrial interest. Comparatively, there is scarce knowledge about the mechanisms that physiologically govern PrtA expression in Serratia In this work, we demonstrate that PrtA production is de-repressed when the bacterial growth temperature decreases from 37°C to 30°C...
January 29, 2018: Journal of Bacteriology
Imke Grimm, Jessika Dumke, Jens Dreier, Cornelius Knabbe, Tanja Vollmer
Streptococcus gallolyticus subsp. gallolyticus is a commensal bacterium of the human gastrointestinal tract, and a pathogen causing infective endocarditis and other biofilm-associated infections via exposed collagen. This study focuses on the characterization of the biofilm formation and collagen adhesion of S. gallolyticus subsp. gallolyticus under different conditions. In this study, it has been observed that the isolate UCN 34 is resistant to 20 mg/ml lysozyme in BHI medium, whereas the strain BAA-2069 builds more biofilm in the presence of lysozyme compared to in a control of BHI without lysozyme...
2018: PloS One
Jinzhi Han, Zhi Ma, Peng Gao, Zhaoxin Lu, Hongxia Liu, Ling Gao, Wenjun Lu, Xiangyu Ju, Fengxia Lv, Haizhen Zhao, Xiaomei Bie
LI-F type peptides are a family of cyclic lipodepsipeptide antibiotics isolated from Paenibacillus polymyxa and display potent activities against positive bacteria including methicillin-resistant S. aureus (MRSA). In this study, we investigated the mechanism of action of LI-F type peptide AMP-jsa9 against a MRSA (S. aureus CICC10790), which is resistant to ciprofloxacin, gentamicin, kanamycin, chloramphenicol, methicillin, and tetracycline. It was found that AMP-jsa9 mainly targets the cell membrane of MRSA and is able to inhibit biofilm formation through killing planktonic bacteria cells...
January 26, 2018: Applied Microbiology and Biotechnology
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