Biofilm formation in cochlear implants with cochlear drug delivery channels in an in vitro model

2007 ◽  
Vol 136 (4) ◽  
pp. 577-582 ◽  
Author(s):  
Trey A. Johnson ◽  
Kimberly A. Loeffler ◽  
Robert A. Burne ◽  
Claude N. Jolly ◽  
Patrick J. Antonelli
Keyword(s):  
Drug Delivery ◽  
Cochlear Implants ◽  
Biofilm Formation ◽  
In Vitro Model ◽  
Vitro Model

Biofilm formation in an in vitro model of cochlear implants with removable magnets

2007 ◽  
Vol 136 (4) ◽  
pp. 583-588 ◽  
Author(s):  
Kimberly A. Loeffler ◽  
Trey A. Johnson ◽  
Robert A. Burne ◽  
Patrick J. Antonelli
Keyword(s):  
Cochlear Implants ◽  
Biofilm Formation ◽  
In Vitro Model ◽  
Vitro Model

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.

Biocompatibility study of quaternized chitosan on the proliferation and differentiation of Caco-2 cells as an in vitro model of the intestinal barrier

2016 ◽  
Vol 32 (1) ◽  
pp. 92-107 ◽  
Author(s):  
Ratjika Wongwanakul ◽  
Suree Jianmongkol ◽  
Pattarapond Gonil ◽  
Warayuth Sajomsang ◽  
Rawiwan Maniratanachote ◽  
...  
Keyword(s):  
Drug Delivery ◽  
In Vitro Model ◽  
Oral Drug Delivery ◽  
Intestinal Barrier ◽  
Oral Drug ◽  
Chitosan Derivatives ◽  
Quaternized Chitosan ◽  
Proliferative Effect ◽  
Vitro Model

The development of different chitosan derivatives for medical applications has increased recently. Among these chitosan derivatives, quaternized chitosan was designed to improve the solubility of chitosan in biological fluids for oral drug delivery while retaining the cationic character for mucoadhesion. However, the biocompatibility of quaternized chitosan on the human intestine is unknown. In this study, we aimed to examine the potential biological effects of quaternized chitosan on the intestinal barrier, in terms of cell proliferation and cell differentiation, using the Caco-2 cell line as an in vitro model. The lower the degree of substitution of quaternized chitosan, the lower the cytotoxic and anti-proliferative effect on Caco-2 cells. In addition, the anti-proliferative effect of quaternized chitosan might induce a cell cycle disturbance and differentiation delay. Long-term continuous exposure (9 days) to quaternized chitosan caused a delay in differentiation of the Caco-2 cells even at non-cytotoxic quaternized chitosan doses (0.005% (w/v)), as shown by the low level of alkaline phosphatase in the quaternized chitosan–treated group compared to the control cells. In contrast, short-term discontinuous exposure to quaternized chitosan (0.005% (w/v) for 4 h/day over 9 days) that more realistically mimics the daily intestinal exposure did not inhibit the intestinal differentiation of Caco-2 cells. Thus, the use of a low degree of substitution and a low concentration of quaternized chitosan resulted in a good biocompatibility to the intestinal barrier supporting the potential usefulness of quaternized chitosan in the application of an oral drug delivery system.

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.

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