scholarly journals Bacterial biofilm formation on cochlear implants in vitro

2018 ◽  
Author(s):  
B Höing ◽  
L Kirchhoff ◽  
J Arnolds ◽  
S Lang ◽  
J Steinmann ◽  
...  
Keyword(s):  
Cochlear Implants ◽  
Biofilm Formation ◽  
Bacterial Biofilm

scholarly journals Glycation of Host Proteins Increases Pathogenic Potential of Porphyromonas gingivalis

2021 ◽  
Vol 22 (21) ◽  
pp. 12084
Author(s):  
Michał Śmiga ◽  
John W. Smalley ◽  
Paulina Ślęzak ◽  
Jason L. Brown ◽  
Klaudia Siemińska ◽  
...  
Keyword(s):  
Porphyromonas Gingivalis ◽  
Biofilm Formation ◽  
Disease Process ◽  
Human Keratinocytes ◽  
Bacterial Biofilm ◽  
Pathogenic Potential ◽  
Glycated Proteins ◽  
Sds Page

The non-enzymatic addition of glucose (glycation) to circulatory and tissue proteins is a ubiquitous pathophysiological consequence of hyperglycemia in diabetes. Given the high incidence of periodontitis and diabetes and the emerging link between these conditions, it is of crucial importance to define the basic virulence mechanisms employed by periodontopathogens such as Porphyromonas gingivalis in mediating the disease process. The aim of this study was to determine whether glycated proteins are more easily utilized by P. gingivalis to stimulate growth and promote the pathogenic potential of this bacterium. We analyzed the properties of three commonly encountered proteins in the periodontal environment that are known to become glycated and that may serve as either protein substrates or easily accessible heme sources. In vitro glycated proteins were characterized using colorimetric assays, mass spectrometry, far- and near-UV circular dichroism and UV–visible spectroscopic analyses and SDS-PAGE. The interaction of glycated hemoglobin, serum albumin and type one collagen with P. gingivalis cells or HmuY protein was examined using spectroscopic methods, SDS-PAGE and co-culturing P. gingivalis with human keratinocytes. We found that glycation increases the ability of P. gingivalis to acquire heme from hemoglobin, mostly due to heme sequestration by the HmuY hemophore-like protein. We also found an increase in biofilm formation on glycated collagen-coated abiotic surfaces. We conclude that glycation might promote the virulence of P. gingivalis by making heme more available from hemoglobin and facilitating bacterial biofilm formation, thus increasing P. gingivalis pathogenic potential in vivo.

Endotracheal tubes coated with a broad-spectrum antibacterial ceragenin reduce bacterial biofilm in an in vitro bench top model

2021 ◽  
Author(s):  
María Consuelo Latorre ◽  
María Jesús Pérez-Granda ◽  
Paul B Savage ◽  
Beatriz Alonso ◽  
Pablo Martín-Rabadán ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
In Vitro Study ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Endotracheal Tubes ◽  
Clinical Strains ◽  
Number Of Cells

Abstract Background Ventilator-associated pneumonia is one of the most common nosocomial infections, caused mainly by bacterial/fungal biofilm. Therefore, it is necessary to develop preventive strategies to avoid biofilm formation based on new compounds. Objectives We performed an in vitro study to compare the efficacy of endotracheal tubes (ETTs) coated with the ceragenin CSA-131 and that of uncoated ETTs against the biofilm of clinical strains of Pseudomonas aeruginosa (PA), Escherichia coli (EC) and Staphylococcus aureus (SA). Methods We applied an in vitro bench top model using coated and uncoated ETTs that were treated with three different clinical strains of PA, EC and SA for 5 days. After exposure to biofilm, ETTs were analysed for cfu count by culture of sonicate and total number of cells by confocal laser scanning microscopy. Results The median (IQR) cfu/mL counts of PA, EC and SA in coated and uncoated ETTs were, respectively, as follows: 1.00 × 101 (0.0–3.3 × 102) versus 3.32 × 109 (6.6 × 108–3.8 × 109), P < 0.001; 0.0 (0.0–5.4 × 103) versus 1.32 × 106 (2.3 × 103–5.0 × 107), P < 0.001; and 8.1 × 105 (8.5 × 101–1.4 × 109) versus 2.7 × 108 (8.6 × 106–1.6 × 1011), P = 0.058. The median (IQR) total number of cells of PA, EC and SA in coated and non-coated ETTs were, respectively, as follows: 11.0 [5.5–not applicable (NA)] versus 87.9 (60.5–NA), P = 0.05; 9.1 (6.7–NA) versus 62.6 (42.0–NA), P = 0.05; and 97.7 (94.6–NA) versus 187.3 (43.9–NA), P = 0.827. Conclusions We demonstrated significantly reduced biofilm formation in coated ETTs. However, the difference for SA was not statistically significant. Future clinical studies are needed to support our findings.

scholarly journals Impact of Bacterial Biofilm Formation on In Vitro and In Vivo Activities of Antibiotics

1998 ◽  
Vol 42 (4) ◽  
pp. 895-898 ◽  
Author(s):  
Silvia Schwank ◽  
Zarko Rajacic ◽  
Werner Zimmerli ◽  
Jürg Blaser
Keyword(s):  
Animal Model ◽  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Phenotypic Resistance ◽  
Vitro Model ◽  
The Impact ◽  
Isogenic Strains

ABSTRACT The impact of bacterial adherence on antibiotic activity was analyzed with two isogenic strains of Staphylococcus epidermidis that differ in the features of their in vitro biofilm formation. The eradication of bacteria adhering to glass beads by amikacin, levofloxacin, rifampin, or teicoplanin was studied in an animal model and in a pharmacokinetically matched in vitro model. The features of S. epidermidis RP62A that allowed it to grow on surfaces in multiple layers promoted phenotypic resistance to antibiotic treatment, whereas strain M7 failed to accumulate, despite initial adherence on surfaces and growth in suspension similar to those for RP62A. Biofilms of S. epidermidis M7 were better eradicated than those of strain RP62A in vitro (46 versus 31%;P < 0.05) as well as in the animal model (39 versus 9%; P < 0.01).

Effect of vancomycin-coated tympanostomy tubes on methicillin-resistant Staphylococcus aureus biofilm formation: in vitro study

2010 ◽  
Vol 124 (6) ◽  
pp. 594-598 ◽  
Author(s):  
C H Jang ◽  
H Park ◽  
Y B Cho ◽  
C H Choi
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Silver Oxide ◽  
In Vitro Study ◽  
Bacterial Biofilm ◽  
Tube Placement ◽  
Tympanostomy Tube ◽  
Methicillin Resistant ◽  
Tympanostomy Tubes

AbstractBackground and objective:Bacterial biofilm formation has been implicated in the high incidence of persistent otorrhoea after tympanostomy tube insertion. It has been suggested that the tube material may be an important factor in the persistence of such otorrhoea. Development of methicillin-resistant Staphylococcus aureus otorrhoea after tympanostomy tube placement is a growing concern. We evaluated the effect of using vancomycin and chitosan coated tympanostomy tubes on the incidence of methicillin-resistant Staphylococcus aureus biofilm formation in vitro.Materials and methods:Three sets each of vancomycin-coated silicone tubes (n = 5), commercial silver oxide coated silicone tubes (n = 5) and uncoated tympanostomy tubes (as controls; n = 5) were compared as regards resistance to methicillin-resistant Staphylococcus aureus biofilm formation after in vitro incubation.Results:Scanning electron microscopy showed that the surfaces of the silver oxide coated tubes supported the formation of thick biofilms with crusts, comparable to the appearance of the uncoated tubes. In contrast, the surface of the vancomycin-coated tympanostomy tubes was virtually devoid of methicillin-resistant Staphylococcus aureus biofilm.Conclusion:Vancomycin-coated tympanostomy tubes resist methicillin-resistant Staphylococcus aureus biofilm formation. Pending further study, such tubes show promise in assisting the control of methicillin-resistant Staphylococcus aureus biofilm formation.

Effects of vancomycin, daptomycin, and tigecycline on coagulase-negative staphylococcus biofilm and bacterial viability within biofilm: an in vitro biofilm model

2016 ◽  
Vol 62 (9) ◽  
pp. 735-743 ◽  
Author(s):  
Barcin Ozturk ◽  
Necati Gunay ◽  
Bulent M. Ertugrul ◽  
Serhan Sakarya
Keyword(s):  
Biofilm Formation ◽  
Treatment Time ◽  
Antimicrobial Effect ◽  
Bacterial Biofilm ◽  
Coagulase Negative Staphylococcus ◽  
Biofilm Inhibition ◽  
Major Barrier ◽  
Biofilm Model ◽  
Repeated Doses

Bacteria may hide in a hydrated polysaccharide matrix known as a biofilm. The structure of the bacterial biofilm renders phagocytosis difficult and increases antibiotic resistance. We hypothesized that repeated doses of antibiotics have an effect on bacteria within the biofilm and that it could inhibit or eradicate biofilm formation. Two clinical biofilm-positive coagulase-negative staphylococcus isolates were evaluated. The effects of antibiotics on preformed and nascent biofilm and on bacterial eradication within the biofilm were determined using different doses of vancomycin, daptomycin, and tigecycline for different durations in an in vitro biofilm model. Vancomycin neither penetrated the biofilm nor had any microbicidal effect on bacteria within the biofilm. Daptomycin had a microbicidal effect on bacteria within the biofilm but had no effect on biofilm inhibition and eradication (independent from dose and treatment time). Tigecycline inhibited and eradicated biofilm formation and had a microbicidal effect on bacteria within the biofilm. In conclusion, (i) biofilm formation appeared to be a major barrier to vancomycin activity, (ii) daptomycin had an antimicrobial effect on the bacteria within the biofilm but not on the biofilm burden, and (iii) tigecycline had effects both on bacteria within the biofilm and on biofilm burden. Thus, both tigecycline and daptomycin might be promising candidates for the treatment of biofilm infections.

scholarly journals Extracellular DNA and Type IV Pilus Expression Regulate the Structure and Kinetics of Biofilm Formation by Nontypeable Haemophilus influenzae

mBio ◽  
2017 ◽  
Vol 8 (6) ◽  
Author(s):  
Jayajit Das ◽  
Elaine Mokrzan ◽  
Vinal Lakhani ◽  
Lucia Rosas ◽  
Joseph A. Jurcisek ◽  
...  
Keyword(s):  
Middle Ear ◽  
In Silico ◽  
Biofilm Formation ◽  
Rational Design ◽  
Bacterial Biofilm ◽  
Confocal Imaging ◽  
Extracellular Dna ◽  
Fractal Structures ◽  
Biofilm Development

ABSTRACT Biofilms formed in the middle ear by nontypeable Haemophilus influenzae (NTHI) are central to the chronicity, recurrence, and refractive nature of otitis media (OM). However, mechanisms that underlie the emergence of specific NTHI biofilm structures are unclear. We combined computational analysis tools and in silico modeling rooted in statistical physics with confocal imaging of NTHI biofilms formed in vitro during static culture in order to identify mechanisms that give rise to distinguishing morphological features. Our analysis of confocal images of biofilms formed by NTHI strain 86-028NP using pair correlations of local bacterial densities within sequential planes parallel to the substrate showed the presence of fractal structures of short length scales (≤10 μm). The in silico modeling revealed that extracellular DNA (eDNA) and type IV pilus (Tfp) expression played important roles in giving rise to the fractal structures and allowed us to predict a substantial reduction of these structures for an isogenic mutant (ΔcomE) that was significantly compromised in its ability to release eDNA into the biofilm matrix and had impaired Tfp function. This prediction was confirmed by analysis of confocal images of in vitro ΔcomE strain biofilms. The fractal structures potentially generate niches for NTHI survival in the hostile middle ear microenvironment by dramatically increasing the contact area of the biofilm with the surrounding environment, facilitating nutrient exchange, and by generating spatial positive feedback to quorum signaling. IMPORTANCE NTHI is a major bacterial pathogen for OM, which is a common ear infection in children worldwide. Chronic OM is associated with bacterial biofilm formation in the middle ear; therefore, knowledge of the mechanisms that underlie NTHI biofilm formation is important for the development of therapeutic strategies for NTHI-associated OM. Our combined approach using confocal imaging of NTHI biofilms formed in vitro and mathematical tools for analysis of pairwise density correlations and agent-based modeling revealed that eDNA and Tfp expression were important factors in the development of fractal structures in NTHI biofilms. These structures may help NTHI survive in hostile environments, such as the middle ear. Our in silico model can be used in combination with laboratory or animal modeling studies to further define the mechanisms that underlie NTHI biofilm development during OM and thereby guide the rational design of, and optimize time and cost for, benchwork and preclinical studies. IMPORTANCE NTHI is a major bacterial pathogen for OM, which is a common ear infection in children worldwide. Chronic OM is associated with bacterial biofilm formation in the middle ear; therefore, knowledge of the mechanisms that underlie NTHI biofilm formation is important for the development of therapeutic strategies for NTHI-associated OM. Our combined approach using confocal imaging of NTHI biofilms formed in vitro and mathematical tools for analysis of pairwise density correlations and agent-based modeling revealed that eDNA and Tfp expression were important factors in the development of fractal structures in NTHI biofilms. These structures may help NTHI survive in hostile environments, such as the middle ear. Our in silico model can be used in combination with laboratory or animal modeling studies to further define the mechanisms that underlie NTHI biofilm development during OM and thereby guide the rational design of, and optimize time and cost for, benchwork and preclinical studies.

scholarly journals Tissue Plasminogen Activator Coating on Implant Surfaces Reduces Staphylococcus aureus Biofilm Formation

2015 ◽  
Vol 82 (1) ◽  
pp. 394-401 ◽  
Author(s):  
Jakub Kwiecinski ◽  
Manli Na ◽  
Anders Jarneborn ◽  
Gunnar Jacobsson ◽  
Marijke Peetermans ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Medical Devices ◽  
Biofilm Formation ◽  
Bacterial Biofilm ◽  
Content Type ◽  
Tissue Plasminogen

ABSTRACTStaphylococcus aureusbiofilm infections of indwelling medical devices are a major medical challenge because of their high prevalence and antibiotic resistance. As fibrin plays an important role inS. aureusbiofilm formation, we hypothesize that coating of the implant surface with fibrinolytic agents can be used as a new method of antibiofilm prophylaxis. The effect of tissue plasminogen activator (tPA) coating onS. aureusbiofilm formation was tested within vitromicroplate biofilm assays and anin vivomouse model of biofilm infection. tPA coating efficiently inhibited biofilm formation by variousS. aureusstrains. The effect was dependent on plasminogen activation by tPA, leading to subsequent local fibrin cleavage. A tPA coating on implant surfaces prevented both early adhesion and later biomass accumulation. Furthermore, tPA coating increased the susceptibility of biofilm infections to antibiotics.In vivo, significantly fewer bacteria were detected on the surfaces of implants coated with tPA than on control implants from mice treated with cloxacillin. Fibrinolytic coatings (e.g., with tPA) reduceS. aureusbiofilm formation bothin vitroandin vivo, suggesting a novel way to prevent bacterial biofilm infections of indwelling medical devices.

scholarly journals Mutation of luxS Affects Biofilm Formation in Streptococcus mutans

2003 ◽  
Vol 71 (4) ◽  
pp. 1972-1979 ◽  
Author(s):  
Justin Merritt ◽  
Fengxia Qi ◽  
Steven D. Goodman ◽  
Maxwell H. Anderson ◽  
Wenyuan Shi
Keyword(s):  
Quorum Sensing ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Microscopic Analysis ◽  
Homoserine Lactone ◽  
Good Evidence ◽  
Genome Project ◽  
Bacterial Biofilm ◽  
Wild Type

ABSTRACT Quorum sensing is a bacterial mechanism for regulating gene expression in response to changes in population density. Many bacteria are capable of acyl-homoserine lactone-based or peptide-based intraspecies quorum sensing and luxS-dependent interspecies quorum sensing. While there is good evidence about the involvement of intraspecies quorum sensing in bacterial biofilm, little is known about the role of luxS in biofilm formation. In this study, we report for the first time that luxS-dependent quorum sensing is involved in biofilm formation of Streptococcus mutans. S. mutans is a major cariogenic bacterium in the multispecies bacterial biofilm commonly known as dental plaque. An ortholog of luxS for S. mutans was identified using the data available in the S. mutans genome project (http://www.genome.ou.edu/smutans.html ). Using an assay developed for the detection of the LuxS-associated quorum sensing signal autoinducer 2 (AI-2), it was demonstrated that this ortholog was able to complement the luxS negative phenotype of Escherichia coli DH5α. It was also shown that AI-2 is indeed produced by S. mutans. AI-2 production is maximal during mid- to late-log growth in batch culture. Mutant strains devoid of the luxS gene were constructed and found to be defective in producing the AI-2 signal. There are also marked phenotypic differences between the wild type and the luxS mutants. Microscopic analysis of in vitro-grown biofilm structure revealed that the luxS mutant biofilms adopted a much more granular appearance, rather than the relatively smooth, confluent layer normally seen in the wild type. These results suggest that LuxS-dependent signal may play an important role in biofilm formation of S. mutans.

scholarly journals New Adapted In Vitro Technology to Evaluate Biofilm Formation and Antibiotic Activity Using Live Imaging under Flow Conditions

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1746
Author(s):  
Cassandra Pouget ◽  
Catherine Dunyach-Remy ◽  
Alix Pantel ◽  
Sophie Schuldiner ◽  
Albert Sotto ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Cell Imaging ◽  
Chronic Wounds ◽  
Chronic Wound ◽  
Live Imaging ◽  
Bacterial Biofilm ◽  
Flow Conditions ◽  
Promising Tool ◽  
Reference Strains

The polymicrobial nature of biofilms and bacterial interactions inside chronic wounds are keys for the understanding of bacterial cooperation. The aim of this present study was to develop a technique to study and visualize biofilm in live imaging under flow conditions (Bioflux™ 200, Fluxion Biosciences). The BiofluxTM system was adapted using an in vitro chronic wound-like medium (CWM) that mimics the environment encountered in ulcers. Two reference strains of Staphylococcus aureus (Newman) and Pseudomonas aeruginosa (PAO1) were injected in the BiofluxTM during 24 h to 72 h in mono and coculture (ratio 1:1, bacteria added simultaneously) in the CWM vs. a control medium (BHI). The quantification of biofilm formation at each time was evaluated by inverted microscopy. After 72 h, different antibiotics (ceftazidime, imipenem, linezolid, oxacillin and vancomycin) at 1x MIC, 10x MIC and 100x MIC were administrated to the system after an automatic increase of the flow that mimicked a debridement of the wound surface. Biofilm studies highlighted that the two species, alone or associated, constituted a faster and thicker biofilm in the CWM compared to the BHI medium. The effect of antibiotics on mature or “debrided” biofilm indicated that some of the most clinically used antibiotic such as vancomycin or imipenem were not able to disrupt and reduce the biofilm biomass. The use of a life cell imaging with an in vitro CWM represents a promising tool to study bacterial biofilm and investigate microbial cooperation in a chronic wound context.

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