scholarly journals Assessment of Inhibitory Effects of Fluoride-Coated Tubes on Biofilm Formation by Using the In Vitro Dental Unit Waterline Biofilm Model

2008 ◽  
Vol 74 (19) ◽  
pp. 5958-5964 ◽  
Author(s):  
Toshiaki Yabune ◽  
Satoshi Imazato ◽  
Shigeyuki Ebisu
Keyword(s):  
Biofilm Formation ◽  
Polyvinylidene Fluoride ◽  
In Vitro Model ◽  
Bacterial Species ◽  
Biofilm Model ◽  
Dental Unit Waterlines ◽  
Vitro Model ◽  
Methylobacterium Mesophilicum ◽  
The One

ABSTRACT This study aimed to establish an in vitro model to simulate biofilms formed in dental unit waterlines (DUWLs) and to investigate the ability of polyvinylidene fluoride (PVDF)-coated tubes to inhibit biofilm formation using this model. The water and biofilm samples were obtained from DUWLs which had been clinically used for 2.5 years, and the predominant bacteria were identified. A conventional polyurethane tube was incubated for 24 to 96 h in the mixed flora of isolated bacteria, and the optimal incubation conditions to simulate a clinically formed biofilm were determined by observation with a scanning electron microscope. Biofilm formation on a PVDF-coated tube was observed using this in vitro model, and the adherence of different bacterial species to conventional and PVDF-coated tubes was assessed. Sphingomonas paucimobilis, Acinetobacter haemolytics, and Methylobacterium mesophilicum were predominantly isolated from contaminated DUWLs. Incubation of the polyurethane tube with the mixed flora containing these three species for 96 h resulted in the formation of a mature biofilm similar to the one clinically observed. The PVDF-coated tube was significantly less adhesive to all three bacterial species than the polyurethane tube (P < 0.05 by the Mann-Whitney U test), and the attachment of small amounts of rods was observed even after incubation with the mixed flora for 96 h. In conclusion, an in vitro biofilm model was obtained by using a mixed flora of bacteria isolated from DUWLs, and the PVDF-coated tube was found to be effective in preventing biofilm formation using this model.

Effect of TrisEDTA and Chlorhexidine 0.12% on an In Vitro-Defined Biofilm Representing the Subgingival Plaque Biofilm of the Dog

2021 ◽  
pp. 089875642110584
Author(s):  
Katherine E. Kling ◽  
Carol W. Maddox ◽  
Sandra Manfra Marretta ◽  
Christina Nowicki ◽  
David J. Schaeffer
Keyword(s):  
In Vitro Model ◽  
Complex Dynamics ◽  
Bacterial Species ◽  
Test Solution ◽  
Deionized Water ◽  
Subgingival Plaque ◽  
Biofilm Model ◽  
Vitro Model ◽  
Plaque Biofilm

This study was designed to investigate the effects of chlorhexidine 0.12%, TrisEDTA (tromethamine ethylenediamintetraacetic acid), and a combination of chlorhexidine 0.12% and TrisEDTA on an in vitro plaque biofilm model comprised of three bacterial species commonly found in canine subgingival plaque. Porphyromonas gulae, Actinomyces canis, and Neisseria canis were grown in a biofilm on polished hydroxyapatite coated titanium alloy pucks for 72 h prior to exposure to one of four test solutions: TrisEDTA, chlorhexidine 0.12%, a combination of TrisEDTA and chlorhexidine 0.12%, or sterile deionized water as a control. Following exposure to the test solution, a sample was collected of the biofilm either immediately or following 24 h of additional incubation in a broth medium. Lower numbers of CFU/mL of Porphyromonas gulae resulted when the biofilm was treated with a solution of chlorhexidine 0.12% and TrisEDTA compared to with chlorhexidine 0.12% alone, TrisEDTA alone, or the control and so this solution can be said to be synergistic against Porphyromonas gulae in this controlled in vitro model. Greater reductions in the numbers of CFU/mL of Actinomyces canis and Neisseria canis resulted from treatment with chlorhexidine 0.12% alone than if treated with the combination of TrisEDTA and chlorhexidine 0.12%. When treated biofilm samples were allowed 24 h of additional growth in fresh media, greater variance resulted and this variance highlights the complex dynamics involved in bacterial growth within a biofilm.

scholarly journals Highly variable effect of sonication to dislodge biofilm-embedded Staphylococcus epidermidis directly quantified by epifluorescence microscopy: an in vitro model study

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Erik T. Sandbakken ◽  
Eivind Witsø ◽  
Bjørnar Sporsheim ◽  
Kjartan W. Egeberg ◽  
Olav A. Foss ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
In Vitro Model ◽  
Laser Scanning Microscopy ◽  
Epifluorescence Microscopy ◽  
Variable Effect ◽  
Prosthetic Joint Infections ◽  
Before And After ◽  
Vitro Model

Abstract Background In cases of prosthetic joint infections, culture of sonication fluid can supplement culture of harvested tissue samples for correct microbial diagnosis. However, discrepant results regarding the increased sensitivity of sonication have been reported in several studies. To what degree bacteria embedded in biofilm are dislodged during the sonication process has to our knowledge not been fully elucidated. In the present in vitro study, we have evaluated the effect of sonication as a method to dislodge biofilm by quantitative microscopy. Methods We used a standard biofilm method to cover small steel plates with biofilm forming Staphylococcus epidermidis ATCC 35984 and carried out the sonication procedure according to clinical practice. By comparing area covered with biofilm before and after sonication with epifluorescence microscopy, the effect of sonication on biofilm removal was quantified. Two series of experiments were made, one with 24-h biofilm formation and another with 72-h biofilm formation. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to confirm whether bacteria were present after sonication. In addition, quantitative bacteriology of sonication fluid was performed. Results Epifluorescence microscopy enabled visualization of biofilm before and after sonication. CLSM and SEM confirmed coccoid cells on the surface after sonication. Biofilm was dislodged in a highly variable manner. Conclusion There is an unexpected high variation seen in the ability of sonication to dislodge biofilm-embedded S. epidermidis in this in vitro model.

scholarly journals Impact of sarA on Antibiotic Susceptibility of Staphylococcus aureus in a Catheter-Associated In Vitro Model of Biofilm Formation

2009 ◽  
Vol 53 (6) ◽  
pp. 2475-2482 ◽  
Author(s):  
Elizabeth C. Weiss ◽  
Horace J. Spencer ◽  
Sonja J. Daily ◽  
Brian D. Weiss ◽  
Mark S. Smeltzer
Keyword(s):  
Staphylococcus Aureus ◽  
Clinical Isolate ◽  
Antimicrobial Susceptibility ◽  
Antibiotic Susceptibility ◽  
Biofilm Formation ◽  
In Vitro Model ◽  
Susceptibility Testing ◽  
Specific Context ◽  
Vitro Model

ABSTRACT Mutation of the staphylococcal accessory regulator (sarA) in Staphylococcus aureus limits but does not abolish the capacity of the organism to form a biofilm. As a first step toward determining whether this limitation is therapeutically relevant, we carried out in vitro studies comparing the relative susceptibility of an S. aureus clinical isolate (UAMS-1) and its isogenic sarA mutant (UAMS-929) in the specific context of a catheter-associated biofilm. The antibiotics tested were daptomycin, linezolid, and vancomycin, all of which were evaluated by using concentrations based on the MIC defined as the breakpoint for a susceptible strain of S. aureus (≤1.0, ≤2.0, and ≤4.0 μg/ml for daptomycin, vancomycin, and linezolid, respectively). Mutation of sarA had no significant impact on the MIC of UAMS-1 for any of the targeted antibiotics, as defined by Etest antimicrobial susceptibility testing. However, mutation of sarA did result in a significant increase in antimicrobial susceptibility to all targeted antibiotics when they were tested in the specific context of a biofilm. Additionally, whether susceptibility was assessed by using UAMS-1 or its sarA mutant, daptomycin was found to be more effective against established S. aureus biofilms than either linezolid or vancomycin.

Comparison of toxicity induced by T-2 toxin on human and rat granulo-monocytic progenitors with an in vitro model

1995 ◽  
Vol 14 (8) ◽  
pp. 672-678 ◽  
Author(s):  
S. Lautraite ◽  
D. Parent-Massin ◽  
B. Rio ◽  
H. Hoellinger
Keyword(s):  
In Vitro Model ◽  
The Other ◽  
Human Umbilical Cord Blood ◽  
Human Umbilical Cord ◽  
Trichothecene Mycotoxin ◽  
Rapid Effect ◽  
Effect Relation ◽  
Vitro Model ◽  
The One

T-2 toxin is a trichothecene mycotoxin produced by vari ous species of fungi. Trichothecenes are known as major contaminants of cereals and their derivatives. In man as well as in animals, T-2 toxin has been shown to induce ali mentary intoxication and, among others, haematological symptoms. Granulo-monocytic progenitors from human umbilical cord blood on the one hand and granulo-mono cytic progenitors from rat bone marrow on the other, were cultured in the presence of T-2 toxin (from 10-7 to 10-10 M) for 14 days. A study of concentration and effect relation ships showed a strong and rapid effect of T-2 toxin on rat colony forming unit-granulocyte and macrophage (CFU-GM) between 5.10-9 M and 10-9 M. On the other hand, human CFU-GM were able to grow in the presence of the same T-2 toxin concentrations. IC50 were determined on day 7, 10 and 14. They were, respectively, 1.6.10-9 M; 3.6.10-9 M; 1.4.10-9 M for human cells, and 2.2.10-9 M; 3.3.10-9 M; 2.6.10 -9 M for rat cells. The present study was prompted by the need to define precisely the cytotoxic and inhibitory T-2 toxin concentrations for rat and human CFU-GM. It is particularly relevant for the investigation of cellular T-2 toxin targets and in order to elucidate the mechanism of trichothecene haematotoxicity.

scholarly journals In-Vitro Model of Scardovia wiggsiae Biofilm Formation and Effect of Nicotine

2020 ◽  
Vol 31 (5) ◽  
pp. 471-476
Author(s):  
Abdulrahman A. Balhaddad ◽  
Hadeel M. Ayoub ◽  
Richard L. Gregory
Keyword(s):  
Biofilm Formation ◽  
In Vitro Model ◽  
Brain Heart Infusion ◽  
Bacterial Interaction ◽  
Colony Forming Units ◽  
Negative Effect ◽  
Vitro Model ◽  
Colony Counter ◽  
Overnight Culture

Abstract Recently, Scardovia wiggsiae has been reported to be strongly associated with caries formation. This study aimed to establish an in vitro model of S. wiggsiae biofilm and to investigate the effect of nicotine on S. wiggsiae colony-forming units (CFUs) growth. S. wiggsiae biofilm was grown overnight using brain-heart infusion (BHI) broth supplemented with 5 g of yeast extract/L (BHI-YE). The overnight culture was used as an inoculum to grow S. wiggsiae biofilm on standardized enamel and dentin samples. Samples were incubated with different nicotine concentrations (0, 0.5, 1, 2, 4, 8, 16 and 32 mg/mL) for 3 days. The dissociated biofilms were diluted, spiral plated on blood agar plates, and incubated for 24 h. CFUs/mL were quantified using an automated colony counter. A two-way ANOVA was used to compare the effect of different nicotine concentrations on S. wiggsiae CFUs. This study demonstrated that S. wiggsiae biofilm could be initiated and formed in vitro. Increased CFUs was observed through 0.5-4 mg/mL and 0.5-8 mg/mL of nicotine using enamel and dentin substrates, respectively. 16 and 32 mg/mL of nicotine were determined as the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC), respectively. S. wiggsiae formed greater biofilm on enamel than dentin specimens in response to the nicotine stimulus. This study demonstrated the negative effect of smoking on increasing S. wiggsiae biofilm. Establishing S. wiggsiae biofilm in vitro may allow researchers in the future to have a better understanding of caries pathogenesis and bacterial interaction.

scholarly journals Biofilm Formation and Effect of Caspofungin on Biofilm Structure of Candida Species Bloodstream Isolates

2009 ◽  
Vol 53 (10) ◽  
pp. 4377-4384 ◽  
Author(s):  
J. A. G. Ferreira ◽  
J. H. Carr ◽  
C. E. F. Starling ◽  
M. A. de Resende ◽  
R. M. Donlan
Keyword(s):  
Biofilm Formation ◽  
In Vitro Model ◽  
Drug Exposure ◽  
Sem Analysis ◽  
Paradoxical Growth ◽  
Vitro Model ◽  
Species Specific ◽  
Biofilm Structure ◽  
Lipid Formulations

ABSTRACT Candida biofilms are microbial communities, embedded in a polymeric matrix, growing attached to a surface, and are highly recalcitrant to antimicrobial therapy. These biofilms exhibit enhanced resistance against most antifungal agents except echinocandins and lipid formulations of amphotericin B. In this study, biofilm formation by different Candida species, particularly Candida albicans, C. tropicalis, and C. parapsilosis, was evaluated, and the effect of caspofungin (CAS) was assessed using a clinically relevant in vitro model system. CAS displayed in vitro activity against C. albicans and C. tropicalis cells within biofilms. Biofilm formation was evaluated after 48 h of antifungal drug exposure, and the effects of CAS on preformed Candida species biofilms were visualized using scanning electron microscopy (SEM). Several species-specific differences in the cellular morphologies associated with biofilms were observed. Our results confirmed the presence of paradoxical growth (PG) in C. albicans and C. tropicalis biofilms in the presence of high CAS concentrations. These findings were also confirmed by SEM analysis and were associated with the metabolic activity obtained by biofilm susceptibility testing. Importantly, these results suggest that the presence of atypical, enlarged, conical cells could be associated with PG and with tolerant cells in Candida species biofilm populations. The clinical implications of these findings are still unknown.

scholarly journals Fusarium and Candida albicans Biofilms on Soft Contact Lenses: Model Development, Influence of Lens Type, and Susceptibility to Lens Care Solutions

2007 ◽  
Vol 52 (1) ◽  
pp. 171-182 ◽  
Author(s):  
Yoshifumi Imamura ◽  
Jyotsna Chandra ◽  
Pranab K. Mukherjee ◽  
Ali Abdul Lattif ◽  
Loretta B. Szczotka-Flynn ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Contact Lens ◽  
Biofilm Formation ◽  
In Vitro Model ◽  
Contact Lenses ◽  
Fungal Keratitis ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Vitro Model

ABSTRACT Fungal keratitis is commonly caused by Fusarium species and less commonly by Candida species. Recent outbreaks of Fusarium keratitis were associated with contact lens wear and with ReNu with MoistureLoc contact lens care solution, and biofilm formation on contact lens/lens cases was proposed to play a role in this outbreak. However, no in vitro model for contact lens-associated fungal biofilm has been developed. In this study, we developed and characterized in vitro models of biofilm formation on various soft contact lenses using three species of Fusarium and Candida albicans. The contact lenses tested were etafilcon A, galyfilcon A, lotrafilcon A, balafilcon A, alphafilcon A, and polymacon. Our results showed that clinical isolates of Fusarium and C. albicans formed biofilms on all types of lenses tested and that the biofilm architecture varied with the lens type. Moreover, differences in hyphal content and architecture were found between the biofilms formed by these fungi. We also found that two recently isolated keratitis-associated fusaria formed robust biofilms, while the reference ATCC 36031 strain (recommended by the International Organization for Standardization guidelines for testing of disinfectants) failed to form biofilm. Furthermore, using the developed in vitro biofilm model, we showed that phylogenetically diverse planktonic fusaria and Candida were susceptible to MoistureLoc and MultiPlus. However, Fusarium biofilms exhibited reduced susceptibility against these solutions in a species- and time-dependent manner. This in vitro model should provide a better understanding of the biology and pathogenesis of lens-related fungal keratitis.

Impact of bacterial species and baseline resistance on fosfomycin efficacy in urinary tract infections

2019 ◽  
Vol 75 (4) ◽  
pp. 988-996 ◽  
Author(s):  
Iain J Abbott ◽  
Jordy Dekker ◽  
Elke van Gorp ◽  
Rixt A Wijma ◽  
Merel N Raaphorst ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Bacterial Species ◽  
Clinical Isolates ◽  
Infection Model ◽  
Limit Of Quantification ◽  
E Coli ◽  
Mutant Prevention Concentration ◽  
Vitro Model ◽  
Tract Infections

Abstract Objectives To assess the antibacterial effects of a single 3 g oral fosfomycin dose on Escherichia coli and Klebsiella pneumoniae clinical isolates within a dynamic bladder infection model. Methods An in vitro model simulating dynamic urinary fosfomycin concentrations was used. Target fosfomycin exposure (Cmax = 1984 mg/L and Tmax = 7.5 h) was validated by LC-MS/MS. Pharmacodynamic responses of 24 E. coli and 20 K. pneumoniae clinical isolates were examined (fosfomycin MIC ≤0.25–128 mg/L). Mutant prevention concentration (MPC), fosfomycin heteroresistance, fosfomycin resistance genes and fosA expression were examined. Pathogen kill and emergence of high-level resistance (HLR; MIC &gt;1024 mg/L) were quantified. Results Following fosfomycin exposure, 20 of 24 E. coli exhibited reductions in bacterial counts below the lower limit of quantification without regrowth, despite baseline fosfomycin MICs up to 128 mg/L. Four E. coli regrew (MIC = 4–32 mg/L) with HLR population replacement. At baseline, these isolates had detectable HLR subpopulations and MPC &gt;1024 mg/L. All E. coli isolates were fosA negative. In contrast, 17 of 20 K. pneumoniae regrew post exposure, 6 with emergence of HLR (proportion = 0.01%–100%). The three isolates without regrowth did not have a detectable HLR subpopulation after dynamic drug-free incubation. All K. pneumoniae had MPC &gt;1024 mg/L and were fosA positive. WGS analysis and fosA expression failed to predict fosfomycin efficacy. Conclusions E. coli and K. pneumoniae isolates demonstrate discrepant responses to a single fosfomycin dose in a dynamic bladder infection in vitro model. Treatment failure against E. coli was related to an HLR subpopulation, not identified by standard MIC testing. Activity against K. pneumoniae appeared limited, regardless of MIC testing, due to universal baseline heteroresistance.

scholarly journals Using Bacteriophages To Reduce Formation of Catheter-Associated Biofilms by Staphylococcus epidermidis

2006 ◽  
Vol 50 (4) ◽  
pp. 1268-1275 ◽  
Author(s):  
John J. Curtin ◽  
Rodney M. Donlan
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biofilm Formation ◽  
In Vitro Model ◽  
Flow Reactor ◽  
Divalent Cations ◽  
Exposure Period ◽  
Model System ◽  
Indwelling Catheters ◽  
Vitro Model

ABSTRACT Use of indwelling catheters is often compromised as a result of biofilm formation. This study investigated if hydrogel-coated catheters pretreated with a coagulase-negative bacteriophage would reduce Staphylococcus epidermidis biofilm formation. Biofilms were developed on hydrogel-coated silicone catheters installed in a modified drip flow reactor. Catheter segments were pretreated with the lytic S. epidermidis bacteriophage 456 by exposing the catheter lumen to a 10-log-PFU/ml culture of the bacteriophage for 1 h at 37°C prior to biofilm formation. The untreated mean biofilm cell count was 7.01 ± 0.47 log CFU/cm2 of catheter. Bacteriophage treatment with and without supplemental divalent cations resulted in log-CFU/cm2 reductions of 4.47 (P < 0.0001) and 2.34 (P = 0.001), respectively. Divalent cation supplementation without bacteriophage treatment provided a 0.67-log-CFU/cm2 reduction (P = 0.053). Treatment of hydrogel-coated silicone catheters with an S. epidermidis bacteriophage in an in vitro model system significantly reduced viable biofilm formation by S. epidermidis over a 24-h exposure period, suggesting the potential of bacteriophage for mitigating biofilm formation on indwelling catheters and reducing the incidence of catheter-related infections.

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