Search results for "BIOFILMS"
showing 10 items of 176 documents
Biofilm development by clinical strains of non-pigmented rapidly growing mycobacteria
2009
AbstractThe relationship between clinical significance of non-pigmented, rapidly growing mycobacteria (NPRGM), in vitro biofilm development and sliding motility was evaluated in this study. One hundred and sixty-eight clinical strains of NPRGM were included. Forty-one of these were clinically significant isolates. Biofilm was formed by 123 strains. Seventy-six biofilm-positive and 25 biofilm-negative strains showed sliding motility. There was a relationship between clinical significance and biofilm development (p <0.000 001), sliding motility (p 0.0037) and species (p <0.000 001). No relationship was found between motility and biofilm development. The ability to develop biofilm is a charact…
Biofilm production in Staphylococcus epidermidis strains, isolated from the skin of hospitalized patients: genetic and phenotypic characteristics.
2014
A major virulence factor of Staphylococcus epidermidis is its ability to form biofilms, permitting it to adhere to a surface and, in turn, to form a mucoid layer on polymer surfaces. Multiple factors have been found to influence bacterial attachment. Currently, this bacterium is commonly associated with hospital infections as a consequence of its ability to colonize, albeit accidentally, medical devices. This study investigated the genetic and phenotypic formation of biofilm in 105 S. epidermidis strains isolated from the skin of hospitalized patients. Fifty-eight of these patients were positive for the mecA gene (MRSE) and 47 were found to be negative (MSSE). Genetic characterizations were…
Zinc oxide and indium tin oxide thin films for the growth and characterization ofShewanella loihicaPV-4 electroactive biofilms
2011
Transition metal oxides (TMO) electrodes provide a suitable platform for spectroscopy- and microscopy-based investigation of viable electroactive biofilms (EABs). Commercially available TMOs, such as indium titanium oxide (ITO), are produced from rare and expensive elements. Thus, there is a significant need to explore alternative technology to meet the demand. ZnO-based TMOs are low-cost and have excellent electrochemical properties. In this study, we report for the first time a model EAB of Shewanella loihica PV-4 on ZnO films deposited on perspex substrates via pulsed laser deposition (PLD). Commercially available ITO electrodes were also used for comparison. 480 Virulence Volume 2 Issue…
Interactions in dual species biofilms between Listeria monocytogenes EGD-e and several strains of Staphylococcus aureus.
2008
International audience; Six environmental isolates of Staphylococcus aureus and one collection strain were investigated for their ability to form monospecies biofilms and dual species biofilms with Listeria monocytogenes EGD-e on stainless steel coupons. All isolates were able to grow as biofilms but their ability to form monospecies biofilms differed. The population of L. monocytogenes EGD-e in dual species biofilms was not affected by the presence of S. aureus isolates except for strain CIP 53.156. The effect of L. monocytogenes EGD-e on the population of S. aureus was strain dependent: S. aureus population either increased or decreased or was not affected in the presence of L. monocytoge…
Marine biominerals: perspectives and challenges for polymetallic nodules and crusts.
2009
Deep sea minerals in polymetallic nodules, crusts and hydrothermal vents are not only formed by mineralization but also by biologically driven processes involving microorganisms (biomineralization). Within the nodules, free-living and biofilm-forming bacteria provide the matrix for manganese deposition, and in cobalt-rich crusts, coccolithophores represent the dominant organisms that act as bio-seeds for an initial manganese deposition. These (bio)minerals are economically important: manganese is an important alloying component and cobalt forms part of special steels in addition to being used, along with other rare metals, in plasma screens, hard-disk magnets and hybrid car motors. Recent p…
Preventing root caries development under oral biofilm challenge in an artificial mouth
2013
Objectives: To study the preventive effects of chlorhexidine against root caries under oral biofilm in an artificial mouth. Study Design: Sixteen human tooth-root disks were inoculated with a salivary sample that was produced by mixing the unstimulated saliva of three adults who had no untreated caries. The disks were incubated in an artificial mouth fed with a 5% sucrose solution three times daily for one week. Eight disks received a twice daily rinse of 0.12% chlorhexidine (test group). The other eight disks were rinsed in distilled water (control). The biofilm was then studied with three techniques: colony forming unit (CFU) counting, scanning electron microscopy (SEM) and confocal laser…
A peptide from human β thymosin as a platform for the development of new anti-biofilm agents for Staphylococcus spp. and Pseudomonas aeruginosa
2016
Conventional antibiotics might fail in the treatment of biofilm-associated infections causing infection recurrence and chronicity. The search for antimicrobial peptides has been performed with the aim to discover novel anti-infective agents active on pathogens in both planktonic and biofilm associated forms. The fragment 9-19 of human thymosin β4 was studied through 1 μs MD simulation. Two main conformations of the peptide were detected, both constituted by a central hydrophobic core and by the presence of peripheral charged residues suggesting a possible mechanism of interaction with two models of biological membranes, related to eukaryotic or bacterial membrane respectively. In addition, …
Effect of C/N shock variation on the performances of a moving bed membrane bioreactor.
2015
Abstract The effect of a sharp variation of C/N ratio in a moving bed membrane bioreactor (MB-MBR) pilot plant treating high strength wastewater has been investigated. The experimental campaign was divided into two periods, each characterized by a different C/N ratio (namely, 2.5 and 15, Period 1 and Period 2, respectively). The MB-MBR system was analyzed in terms of organic carbon removal, nitrification efficiency, biokinetic activity and fouling behavior. The results showed that the nitrification process was severely affected by lower C/N value and by high concentration of ammonia. It was noticed an extensive stress effect on the autotrophic bacteria. Furthermore, it was observed an incre…
Nanostructured medical sutures with antibacterial properties
2014
Bacterial repellence in suture materials is a desirable property that can potentially improve the healing process by preventing infection. We describe a method for generating nanostructures at the surface of commercial sutures of different composition, and their potential for preventing biofilm formation. We show how bacteria attachment is altered in the presence of nanosized topographies and identify optimum designs for preventing it without compromising biocompatibility and applicability in terms of nanostructure robustness or tissue friction. These studies open new possibilities for flexible and cost-effective realization of topography-based antibacterial coatings for absorbable biomedic…
The evolution and changing ecology of the African hominid oral microbiome
2021
Significance The microbiome plays key roles in human health, but little is known about its evolution. We investigate the evolutionary history of the African hominid oral microbiome by analyzing dental biofilms of humans and Neanderthals spanning the past 100,000 years and comparing them with those of chimpanzees, gorillas, and howler monkeys. We identify 10 core bacterial genera that have been maintained within the human lineage and play key biofilm structural roles. However, many remain understudied and unnamed. We find major taxonomic and functional differences between the oral microbiomes of Homo and chimpanzees but a high degree of similarity between Neanderthals and modern humans, incl…