scholarly journals Smart Nanomaterials for Treatment of Biofilm in Orthopedic Implants

2021 ◽  
Vol 9 ◽  
Author(s):  
Qimin Hong ◽  
Shicheng Huo ◽  
Haozheng Tang ◽  
Xinhua Qu ◽  
Bing Yue
Keyword(s):  
Smart Materials ◽  
Bacterial Communities ◽  
Biofilm Formation ◽  
Defense Mechanisms ◽  
Orthopedic Implants ◽  
Immune Defense ◽  
Persistent Infections ◽  
Pathogenic Biofilms ◽  
Nano Size ◽  
Made In

Biofilms refer to complex bacterial communities that are attached to the surface of animate or inanimate objects, which highly resist the antibiotics or the host immune defense mechanisms. Pathogenic biofilms in medicine are general, chronic, and even costly, especially on medical devices and orthopedic implants. Bacteria within biofilms are the cause of many persistent infections, which are almost impossible to eradicate. Though some progress has been made in comprehending the mechanisms of biofilm formation and persistence, novel alternative compounds or strategies and effective anti-biofilm antibiotics are still lacking. Smart materials of nano size which are able to respond to an external stimulus or internal environment have a great range of applications in clinic. Recently, smart nanomaterials with or without carriage of antibiotics, targeting specific bacteria and biofilm under some stimuli, have shown great potential for pathogenic biofilm and resident bacteria eradication. First, this review briefly summarizes and describes the significance of biofilms and the process of biofilm formation. Then, we focus on some of the latest research studies involving biofilm elimination, which probably could be applied in orthopedic implants. Finally, some outstanding challenges and limitations that need to be settled urgently in order to make smart nanomaterials effectively target and treat implant biofilms are also discussed. It is hoped that there will be more novel anti-biofilm strategies for biofilm infection in the prospective future.

Phagocytosis of Staphylococci Biofilms by Polymorphonuclear Neutrophils: S. aureus and S. epidermidis Differ with Regard to Their Susceptibility Towards the Host Defense

2009 ◽  
Vol 32 (9) ◽  
pp. 565-573 ◽  
Author(s):  
Frank Guenther ◽  
Petra Stroh ◽  
Christof Wagner ◽  
Ursula Obst ◽  
Gertrud Maria Hänsch
Keyword(s):  
Host Defense ◽  
Defense Mechanisms ◽  
Orthopedic Implants ◽  
Time Lapse ◽  
Polymorphonuclear Neutrophils ◽  
Bacterial Strains ◽  
Phagocytic Cells ◽  
First Line ◽  
Persistent Infections

Bacteria organized in biofilms are a common cause of relapsing or persistent infections. In patients receiving orthopedic implants, such as endoprostheses or osteosynthesis materials, Staphylococcus aureus and S. epidermidis are prevalent and it is widely assumed that bacteria in biofilms are not only relatively resistant towards antibiotics and biocides, but also towards host defense mechanisms. In that context, we addressed the question how polymorphonuclear neutrophils (PMN), the “first line defense” against bacterial infection, interact with biofilms generated in vitro. By time-lapse video microscopy, we observed migration of PMN towards the biofilms. In the case of S. aureus, the PMN moved across the biofilm and took up bacteria as they moved along. On S. epidermidis, in contrast, the PMN were rather immobile, and phagocytosis was limited to bacteria in the immediate vicinity. By labeling the bacteria within the biofilm with 3H-thymidine we found that S. aureus biofilms were more sensitive towards the PMN attack than S. epidermidis. Following phagocytosis of either bacteria strain, the PMN underwent apoptosis, in line with the dogma, that phagocytosis induces programmed cell-death in order to prevent spilling of the bactericidal and cytotoxic entities. In conclusion, biofilms are not inherently protected against the attack by phagocytic cells; their sensitivity, however, varies among bacterial strains, presumably due to properties of the extracellular biofilm matrix affecting the motility of PMN on the film.

scholarly journals Silver nanoparticles as an alternative strategy against bacterial biofilms.

1970 ◽  
Vol 60 (4) ◽  
Author(s):  
Katarzyna Markowska ◽  
Anna M Grudniak ◽  
Krystyna I Wolska
Keyword(s):  
Silver Nanoparticles ◽  
Immune System ◽  
Medical Devices ◽  
Bacterial Communities ◽  
Biofilm Formation ◽  
Biological Action ◽  
Bacterial Biofilms ◽  
Human Immune System ◽  
Persistent Infections ◽  
Human Immune

Biofilms are complex bacterial communities that resist the action of antibiotics and the human immune system. Bacteria within biofilms are the cause of numerous, almost impossible to eradicate, persistent infections. Biofilms can form on many medical devices and implants, and so have an enormous impact on medicine. Due to the lack of effective anti-biofilm antibiotics, novel alternative compounds or strategies are urgently required. This review describes some of the latest approaches in the field of biofilm treatment. New anti-biofilm technologies target different stages in the biofilm formation process. Some act to modify the colonized biomaterials to make them resistant to biofilm formation. One potentially important candidate treatment uses silver nanoparticles that show anti-bacterial and anti-biofilm activity. The biological action of nano-silver is complex and seems to involve a number of pathways. However, there have been few reports on the anti-biofilm activity of silver nanoparticles and the precise mechanism underlying their action remains unresolved. Here, we describe some anti-biofilm approaches employing AgNPs and consider the challenges and problems that need to be addressed in order to make silver nanoparticles a part of an effective anti-biofilm strategy.

scholarly journals Superhydrophobic Nanocoatings as Intervention against Biofilm-Associated Bacterial Infections

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1046
Author(s):  
Yinghan Chan ◽  
Xun Hui Wu ◽  
Buong Woei Chieng ◽  
Nor Azowa Ibrahim ◽  
Yoon Yee Then
Keyword(s):  
Biofilm Formation ◽  
Bacterial Infections ◽  
Therapeutic Strategies ◽  
Public Healthcare ◽  
Persistent Infections ◽  
Promising Strategy ◽  
Antimicrobial Interventions ◽  
Novel Therapeutic Strategies ◽  
Insight Into ◽  
Microbial Attachment

Biofilm formation represents a significant cause of concern as it has been associated with increased morbidity and mortality, thereby imposing a huge burden on public healthcare system throughout the world. As biofilms are usually resistant to various conventional antimicrobial interventions, they may result in severe and persistent infections, which necessitates the development of novel therapeutic strategies to combat biofilm-based infections. Physicochemical modification of the biomaterials utilized in medical devices to mitigate initial microbial attachment has been proposed as a promising strategy in combating polymicrobial infections, as the adhesion of microorganisms is typically the first step for the formation of biofilms. For instance, superhydrophobic surfaces have been shown to possess substantial anti-biofilm properties attributed to the presence of nanostructures. In this article, we provide an insight into the mechanisms underlying biofilm formation and their composition, as well as the applications of nanomaterials as superhydrophobic nanocoatings for the development of novel anti-biofilm therapies.

scholarly journals Eugenol-Functionalized Magnetite Nanoparticles Modulate Virulence and Persistence in Pseudomonas aeruginosa Clinical Strains

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2189
Author(s):  
Hamzah Basil Mohammed ◽  
Sajjad Mohsin I. Rayyif ◽  
Carmen Curutiu ◽  
Alexandra Catalina Birca ◽  
Ovidiu-Cristian Oprea ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Spherical Shape ◽  
Infectious Process ◽  
Phenotypic Resistance ◽  
Persistent Infections ◽  
Resistant Mutants ◽  
Subinhibitory Concentrations ◽  
Pathogenic Agents ◽  
Soluble Enzymes

Efficient antibiotics to cure Pseudomonas aeruginosa persistent infections are currently insufficient and alternative options are needed. A promising lead is to design therapeutics able to modulate key phenotypes in microbial virulence and thus control the progression of the infectious process without selecting resistant mutants. In this study, we developed a nanostructured system based on Fe3O4 nanoparticles (NPs) and eugenol, a natural plant-compound which has been previously shown to interfere with microbial virulence when utilized in subinhibitory concentrations. The obtained functional NPs are crystalline, with a spherical shape and 10–15 nm in size. The subinhibitory concentrations (MIC 1/2) of the eugenol embedded magnetite NPs (Fe3O4@EUG) modulate key virulence phenotypes, such as attachment, biofilm formation, persister selection by ciprofloxacin, and the production of soluble enzymes. To our knowledge, this is the first report on the ability of functional magnetite NPs to modulate P. aeruginosa virulence and phenotypic resistance; our data highlights the potential of these bioactive nanostructures to be used as anti-pathogenic agents.

scholarly journals Fibrinolysis: A Primordial System Linked to the Immune Response

2021 ◽  
Vol 22 (7) ◽  
pp. 3406
Author(s):  
Robert L. Medcalf ◽  
Charithani B. Keragala
Keyword(s):  
Binding Sites ◽  
Defense Mechanisms ◽  
Immune Cell ◽  
Immune Defense ◽  
Surface Proteins ◽  
Cell Behavior ◽  
Phylogenetic Studies ◽  
Blood Clots ◽  
Lower Vertebrates ◽  
Almost All

The fibrinolytic system provides an essential means to remove fibrin deposits and blood clots. The actual protease responsible for this is plasmin, formed from its precursor, plasminogen. Fibrin is heralded as it most renowned substrate but for many years plasmin has been known to cleave many other substrates, and to also activate other proteolytic systems. Recent clinical studies have shown that the promotion of plasmin can lead to an immunosuppressed phenotype, in part via its ability to modulate cytokine expression. Almost all immune cells harbor at least one of a dozen plasminogen receptors that allows plasmin formation on the cell surface that in turn modulates immune cell behavior. Similarly, a multitude of pathogens can also express their own plasminogen activators, or contain surface proteins that provide binding sites host plasminogen. Plasmin formed under these circumstances also empowers these pathogens to modulate host immune defense mechanisms. Phylogenetic studies have revealed that the plasminogen activating system predates the appearance of fibrin, indicating that plasmin did not evolve as a fibrinolytic protease but perhaps has its roots as an immune modifying protease. While its fibrin removing capacity became apparent in lower vertebrates these primitive under-appreciated immune modifying functions still remain and are now becoming more recognised.

scholarly journals Comparative Genomics Within the Bacillus Genus Reveal the Singularities of Two Robust Bacillus amyloliquefaciens Biocontrol Strains

2015 ◽  
Vol 28 (10) ◽  
pp. 1102-1116 ◽  
Author(s):  
M. C. Magno-Pérez-Bryan ◽  
P. M. Martínez-García ◽  
J. Hierrezuelo ◽  
P. Rodríguez-Palenzuela ◽  
E. Arrebola ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Biofilm Formation ◽  
Bacillus Amyloliquefaciens ◽  
Communication Systems ◽  
Defense Mechanisms ◽  
Ad Hoc ◽  
Cell Communication ◽  
Defense Responses ◽  
Microbial Pathogens ◽  
Stimulate Plant Growth

Bacillus amyloliquefaciens CECT 8237 and CECT 8238, formerly known as Bacillus subtilis UMAF6639 and UMAF6614, respectively, contribute to plant health by facing microbial pathogens or inducing the plant’s defense mechanisms. We sequenced their genomes and developed a set of ad hoc scripts that allowed us to search for the features implicated in their beneficial interaction with plants. We define a core set of genes that should ideally be found in any beneficial Bacillus strain, including the production of secondary metabolites, volatile compounds, metabolic plasticity, cell-to-cell communication systems, and biofilm formation. We experimentally prove that some of these genetic elements are active, such as i) the production of known secondary metabolites or ii) acetoin and 2-3-butanediol, compounds that stimulate plant growth and host defense responses. A comparison with other Bacillus genomes permits us to find differences in the cell-to-cell communication system and biofilm formation and to hypothesize variations in their persistence and resistance ability in diverse environmental conditions. In addition, the major protection provided by CECT 8237 and CECT 8238, which is different from other Bacillus strains against bacterial and fungal melon diseases, permits us to propose a correlation with their singular genetic background and determine the need to search for additional blind biocontrol-related features.

scholarly journals A novel calcium-concentrating compartment drives biofilm formation and persistent infections

2020 ◽  
Author(s):  
Alona Keren-Paz ◽  
Malena Cohen-Cymberknoh ◽  
Dror Kolodkin-Gal ◽  
Iris Karunker ◽  
Simon Dersch ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Calcium Uptake ◽  
Molecular Mechanisms ◽  
Model Organism ◽  
Bacterial Cells ◽  
Mineral Layer ◽  
Cellular Compartment ◽  
Persistent Infections ◽  
Cellular Metal

AbstractBacterial biofilms produce a robust internal mineral layer, composed of calcite, which strengthens the colony and protects the residing bacteria from antibiotics. In this work, we provide evidence that the assembly of a functional mineralized macro-structure begins with mineral precipitation within a defined cellular compartment in a differentiated subpopulation of cells. Transcriptomic analysis of a model organism, Bacillus subtilis, revealed that calcium was essential for activation of the biofilm state, and highlighted the role of cellular metal homeostasis and carbon metabolism in biomineralization. The molecular mechanisms promoting calcite formation were conserved in pathogenic Pseudomonas aeruginosa biofilms, resulting in formation of calcite crystals tightly associated with bacterial cells in sputum samples collected from cystic fibrosis patients. Biomineralization inhibitors targeting calcium uptake and carbonate accumulation significantly reduced the damage inflicted by P. aeruginosa biofilms to lung tissues. Therefore, better understanding of the conserved molecular mechanisms promoting biofilm calcification can path the way to the development of novel classes of antibiotics to combat otherwise untreatable biofilm infections.

scholarly journals Linearmycins Activate a Two-Component Signaling System Involved in Bacterial Competition and Biofilm Morphology

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Reed M. Stubbendieck ◽  
Paul D. Straight
Keyword(s):  
Antibiotic Resistance ◽  
Abc Transporter ◽  
Bacterial Communities ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Bioactive Metabolites ◽  
Signaling System ◽  
Content Type ◽  
Two Component ◽  
Analytical Approaches

ABSTRACT Bacteria use two-component signaling systems to adapt and respond to their competitors and changing environments. For instance, competitor bacteria may produce antibiotics and other bioactive metabolites and sequester nutrients. To survive, some species of bacteria escape competition through antibiotic production, biofilm formation, or motility. Specialized metabolite production and biofilm formation are relatively well understood for bacterial species in isolation. How bacteria control these functions when competitors are present is not well studied. To address fundamental questions relating to the competitive mechanisms of different species, we have developed a model system using two species of soil bacteria, Bacillus subtilis and Streptomyces sp. strain Mg1. Using this model, we previously found that linearmycins produced by Streptomyces sp. strain Mg1 cause lysis of B. subtilis cells and degradation of colony matrix. We identified strains of B. subtilis with mutations in the two-component signaling system yfiJK operon that confer dual phenotypes of specific linearmycin resistance and biofilm morphology. We determined that expression of the ATP-binding cassette (ABC) transporter yfiLMN operon, particularly yfiM and yfiN, is necessary for biofilm morphology. Using transposon mutagenesis, we identified genes that are required for YfiLMN-mediated biofilm morphology, including several chaperones. Using transcriptional fusions, we found that YfiJ signaling is activated by linearmycins and other polyene metabolites. Finally, using a truncated YfiJ, we show that YfiJ requires its transmembrane domain to activate downstream signaling. Taken together, these results suggest coordinated dual antibiotic resistance and biofilm morphology by a single multifunctional ABC transporter promotes competitive fitness of B. subtilis. IMPORTANCE DNA sequencing approaches have revealed hitherto unexplored diversity of bacterial species in a wide variety of environments that includes the gastrointestinal tract of animals and the rhizosphere of plants. Interactions between different species in bacterial communities have impacts on our health and industry. However, many approaches currently used to study whole bacterial communities do not resolve mechanistic details of interspecies interactions, including how bacteria sense and respond to their competitors. Using a competition model, we have uncovered dual functions for a previously uncharacterized two-component signaling system involved in specific antibiotic resistance and biofilm morphology. Insights gleaned from signaling within interspecies interaction models build a more complete understanding of gene functions important for bacterial communities and will enhance community-level analytical approaches.

Immunotherapy of Chemically-Induced Tumors in the Hamster Cheek Pouch with Dinitrochlorobenzene

1978 ◽  
Vol 57 (4) ◽  
pp. 625-630 ◽  
Author(s):  
Martin Marshack ◽  
Patrick Toto ◽  
Ronald Kerman
Keyword(s):  
Defense Mechanisms ◽  
Immune Defense ◽  
Lymphoid Cells ◽  
Cheek Pouch ◽  
Hamster Cheek Pouch ◽  
Time Intervals ◽  
Tumor Induction ◽  
Chemically Induced ◽  
Induced Tumors ◽  
Tumor Area

Immune stimulation with an agent such as dinitrochlorobenzene (DNCB) may delay chemcal carcinogenesis. Dimethylbenzanthracene (DMBA) was used to chemically induce tumors in the hamster buccal pouch. Hamsters were studied for the effect of DNCB sensitization in the buccal pouch prior to or after DMBA tumor induction. At appropriate time intervals the hamsters were sacrificed and each cheek pouch was examined histologically for the development of DMBA-induced tumors and for the presence of lymphoid cells infiltrating the tumor site. The results show that DNCB immunotherapy or immunoprophylaxis prior to or following DMBA tumor induction can alter the type of tumor produced and stimulate an infiltration of lymphoid cells into the tumor area probably invoking immune defense mechanisms.

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