Sinonasal Stent Coated with Slow-Release Varnish of Chlorhexidine Has Sustained Protection against Bacterial Biofilm Growth in the Sinonasal Cavity: An In Vitro Study

The aim of the study was to develop a sustained-release varnish (SRV) containing chlorhexidine (CHX) for sinonasal stents (SNS) to reduce bacterial growth and biofilm formation in the sinonasal cavity. Segments of SNS were coated with SRV-CHX or SRV-placebo and exposed daily to bacterial cultures of Staphylococcus aureus subsp. aureus ATCC 25923 or Pseudomonas aeruginosa ATCC HER-1018 (PAO1). Anti-bacterial effects were assessed by disc diffusion assay and planktonic-based activity assay. Biofilm formation on the coated stents was visualized by confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM). The metabolic activity of the biofilms was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method. Disc diffusion assay showed that SRV-CHX-coated SNS segments inhibited bacterial growth of S. aureus subsp. aureus ATCC 25923 for 26 days and P. aeruginosa ATCC HER-1018 for 19 days. CHX was released from coated SNS segments in a pH 6 medium up to 30 days, resulting in growth inhibition of S. aureus subsp. aureus ATCC 25923 for 22 days and P. aeruginosa ATCC HER-1018 for 24 days. The MTT assay showed a reduction of biofilm growth on the coated SNS by 69% for S. aureus subsp. aureus ATCC 25923 and 40% for P. aeruginosa ATCC HER-1018 compared to the placebo stent after repeated exposure to planktonic growing bacteria. CLSM and HR-SEM showed a significant reduction of biofilm formation on the SRV-CHX-coated SNS segments. Coating of SNS with SRV-CHX maintains a sustained delivery of CHX, providing an inhibitory effect on the bacterial growth of S. aureus subsp. aureus ATCC 25923 and P. aeruginosa ATCC HER-1018 for approximately 3 weeks.

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The Interaction of N-Acetylcysteine and Serum Transferrin Promotes Bacterial Biofilm Formation

Cellular Physiology and Biochemistry ◽

10.1159/000487566 ◽

2018 ◽

Vol 45 (4) ◽

pp. 1399-1409 ◽

Cited By ~ 7

Author(s):

Supeng Yin ◽

Bei Jiang ◽

Guangtao Huang ◽

Yulong Zhang ◽

Bo You ◽

...

Keyword(s):

Human Serum ◽

Biofilm Formation ◽

Laser Scanning ◽

Serum Proteins ◽

Venous Catheter ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Bacterial Strains

Background/Aims: N-acetylcysteine (NAC) is a novel and promising agent with activity against bacterial biofilms. Human serum also inhibits biofilm formation by some bacteria. We tested whether the combination of NAC and human serum offers greater anti-biofilm activity than either agent alone. Methods: Microtiter plate assays and confocal laser scanning microscopy were used to evaluate bacterial biofilm formation in the presence of NAC and human serum. qPCR was used to examine expression of selected biofilm-associated genes. Extracellular matrix (ECM) was observed by transmission electron microscopy. The antioxidants GSH or ascorbic acid were used to replace NAC, and human transferrin, lactoferrin, or bovine serum albumin were used to replace serum proteins in biofilm formation assays. A rat central venous catheter model was developed to evaluate the effect of NAC on biofilm formation in vivo. Results: NAC and serum together increased biofilm formation by seven different bacterial strains. In Staphylococcus aureus, expression of genes for some global regulators and for genes in the ica-dependent pathway increased markedly. In Pseudomonas aeruginosa, transcription of las, the PQS quorum sensing (QS) systems, and the two-component system GacS/GacA increased significantly. ECM production by S. aureus and P. aeruginosa was also enhanced. The potentiation of biofilm formation is due mainly to interaction between NAC and transferrin. Intravenous administration of NAC increased colonization by S. aureus and P. aeruginosa on implanted catheters. Conclusions: NAC used intravenously or in the presence of blood increases bacterial biofilm formation rather than inhibits it.

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

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkab019 ◽

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.

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Organo-Selenium-Containing Polyester Bandage Inhibits Bacterial Biofilm Growth on the Bandage and in the Wound

Biomedicines ◽

10.3390/biomedicines8030062 ◽

2020 ◽

Vol 8 (3) ◽

pp. 62

Author(s):

Phat Tran ◽

Tyler Enos ◽

Keaton Luth ◽

Abdul Hamood ◽

Coby Ray ◽

...

Keyword(s):

Wound Infection ◽

Wound Dressing ◽

Laser Scanning ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Bacterial Strains ◽

Biofilm Growth ◽

Biofilm Model

The dressing material of a wound plays a key role since bacteria can live in the bandage and keep re-infecting the wound, thus a bandage is needed that blocks biofilm in the bandage. Using an in vivo wound biofilm model, we examined the effectiveness of an organo-selenium (OS)-coated polyester dressing to inhibit the growth of bacteria in a wound. Staphylococcus aureus (as well as MRSA, Methicillin resistant Staph aureus), Stenotrophomonas maltophilia, Enterococcus faecalis, Staphylococcus epidermidis, and Pseudomonas aeruginosa were chosen for the wound infection study. All the bacteria were enumerated in the wound dressing and in the wound tissue under the dressing. Using colony-forming unit (CFU) assays, over 7 logs of inhibition (100%) was found for all the bacterial strains on the material of the OS-coated wound dressing and in the tissue under that dressing. Confocal laser scanning microscopy along with IVIS spectrum in vivo imaging confirmed the CFU results. Thus, the dressing acts as a reservoir for a biofilm, which causes wound infection. The same results were obtained after soaking the dressing in PBS at 37 °C for three months before use. These results suggest that an OS coating on polyester dressing is both effective and durable in blocking wound infection.

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Effects of Bleaching Associated with Er:YAG and Nd:YAG Laser on Enamel Structure and Bacterial Biofilm Formation

Scanning ◽

10.1155/2021/6400605 ◽

2021 ◽

Vol 2021 ◽

pp. 1-7

Author(s):

Xiuxiu Hou ◽

Keyong Yuan ◽

Zhengwei Huang ◽

Rui Ma

Keyword(s):

Nd:Yag Laser ◽

Biofilm Formation ◽

Laser Scanning ◽

Fusobacterium Nucleatum ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Streptococcus Sanguis ◽

Enamel Structure ◽

Significant Difference

Objective. To compare the effects of bleaching associated with Er:YAG and Nd:YAG laser on enamel structure and mixed biofilm formation on teeth surfaces. Materials and Methods. Sixty-eight enamel samples were randomly divided into four groups ( n = 17 ), control, Opalescence Boost only, Opalescence Boost plus Er: YAG laser, and Opalescence Boost plus Nd:YAG laser. The structure was observed using SEM after bleaching. Subsequently, the treated enamel samples were also cultured in suspensions of Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus, and Fusobacterium nucleatum (Fn) for 24 and 48 h. Biofilm formation was quantified by crystal violet staining, and the structure was visualized by confocal laser scanning microscopy. The data were analyzed using the Kruskal-Wallis method. Results. The enamel structure significantly changed after bleaching. There was no obvious difference in the biofilm formation after 24 h; however, after 48 hours, the amount of biofilm increased significantly. Remarkably, the amount was significantly higher on enamel bleached only, however, there was no significant difference between samples bleached with Er:YAG or Nd:YAG laser compared to the control. Conclusions. Bleaching only appeared to markedly promote biofilm formation after 48 h, and the biofilms on samples bleached with Er:YAG or Nd:YAG laser did not change significantly, showing that bleaching with Er:YAG or Nd:YAG laser can be safely applied in clinical practice.

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Sanguinarine Inhibits Mono- and Dual-Species Biofilm Formation by Candida albicans and Staphylococcus aureus and Induces Mature Hypha Transition of C. albicans

Pharmaceuticals ◽

10.3390/ph13010013 ◽

2020 ◽

Vol 13 (1) ◽

pp. 13 ◽

Cited By ~ 1

Author(s):

Weidong Qian ◽

Wenjing Wang ◽

Jianing Zhang ◽

Miao Liu ◽

Yuting Fu ◽

...

Keyword(s):

Biofilm Formation ◽

Laser Scanning ◽

Inhibitory Concentration ◽

Fluorescent Dyes ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Matrix Component ◽

New Agents ◽

Diffusion Assay ◽

And Staphylococcus Aureus

Previous studies have reported that sanguinarine possesses inhibitory activities against several microorganisms, but its effects on mono- and dual-species biofilms of C. albicans and S. aureus have not been fully elucidated. In this study, we aimed to evaluate the efficacy of sanguinarine for mono- and dual-species biofilms and explore its ability to induce the hypha-to-yeast transition of C. albicans. The results showed that the minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC90) of sanguinarine against C. albicans and S. aureus mono-species biofilms was 4, and 2 μg/mL, respectively, while the MIC and MBIC90 of sanguinarine against dual-species biofilms was 8, and 4 μg/mL, respectively. The decrease in the levels of matrix component and tolerance to antibiotics of sanguinarine-treated mono- and dual-species biofilms was revealed by confocal laser scanning microscopy combined with fluorescent dyes, and the gatifloxacin diffusion assay, respectively. Meanwhile, sanguinarine at 128 and 256 μg/mL could efficiently eradicate the preformed 24-h biofilms by mono- and dual-species, respectively. Moreover, sanguinarine at 8 μg/mL could result in the transition of C. albicans from the mature hypha form to the unicellular yeast form. Hence, this study provides useful information for the development of new agents to combat mono- and dual-species biofilm-associated infections, caused by C. albicans and S. aureus.

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Biofilm Formation on Breast Implant Surfaces By Major Gram-Positive Bacterial Pathogens

Aesthetic Surgery Journal ◽

10.1093/asj/sjaa416 ◽

2020 ◽

Author(s):

Gabriel Rezende-Pereira ◽

Julia P Albuquerque ◽

Monica C Souza ◽

Barbara A Nogueira ◽

Marlei G Silva ◽

...

Keyword(s):

Clinical Isolate ◽

Biofilm Formation ◽

Laser Scanning ◽

Bacterial Pathogens ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Gram Positive ◽

Reference Strains ◽

Collagen Treatment

Abstract Background Bacterial biofilm on surfaces of mammary implants is a predisposing factor for several outcomes. Since Gram-positive bacteria are potential agents of biomaterial-associated infections (BAIs), their abilities to form biofilm on breast implants should be elucidated. Objectives To evaluate biofilm formation on different mammary prosthesis surfaces by major Gram-positive bacterial pathogens involved in BAIs. Methods We initially evaluated biofilm formation on polystyrene plates with and without fibrinogen or collagen for one reference strain and one clinical isolate of Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus pyogenes. We also tested the ability of clinical isolates to form biofilm on four different implant surfaces: polyurethane foam and smooth, microtextured and standard textured silicone. Biofilm structure and cell viability were observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results All strains showed strong biofilm formation on polystyrene. After fibrinogen or collagen treatment, biofilm formation varied. With fibrinogen, reference strains of S. aureus and S. pyogenes increased biofilm formation (p<0.05). Reference strains of all species and the clinical isolate of S. pyogenes increased biofilm formation after collagen treatment (p<0.05). In general, S. aureus showed higher capacity to produce biofilm. SEM showed biofilm attached to all surfaces tested, with the presence of extracellular polymeric substances and voids. Viable cells were more frequent for E. faecalis and S. pyogenes. Conclusions All species produced biofilm on all prosthesis surfaces and under different conditions. Micrographies indicated thicker bacterial biofilm formation on microtextured and/or standard textured silicone by all species, except E. faecalis.

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Protozoan impact on bacterial biofilm formation

Biological Letters ◽

10.2478/v10120-009-0017-x ◽

2010 ◽

Vol 47 (1) ◽

pp. 3-10 ◽

Cited By ~ 4

Author(s):

Krzysztof Rychert ◽

Thomas Neu

Keyword(s):

Activated Sludge ◽

Biofilm Formation ◽

Laser Scanning ◽

Grazing Pressure ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Protozoan Community ◽

Biofilm Development ◽

The Impact

Protozoan impact on bacterial biofilm formationConfocal laser scanning microscopy in combination with digital image analysis was used to assess the impact of protozoa on bacterial colonisation of surfaces. Bacterial biofilms were developed from activated sludge in microscope flow cells and were exposed to the grazing pressure of protozoa. The protozoan community from healthy activated sludge and a culture of flagellateBodo saltanswere used as grazers. Experiments comprised 48-h incubations in 3 treatment variants: bacteria with protozoa, bacteria with protozoa added after some time and bacteria without protozoa. When necessary, the elimination of protozoa from the inoculum was carried out with cycloheximide and NiSO4. Experiments demonstrated that protozoa from healthy activated sludge initially disturbed the biofilm development but later they could stimulate its growth. Similar results could be established in the experiment withBodo saltans(inoculum: 1000 cells/ml), however differences were not statistically significant. The finding that protozoa support biofilm development during specific stages may be relevant for biofilm studies with mixed environmental biofilm communities.

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Role of Exopolysaccharides in Pseudomonas aeruginosa Biofilm Formation and Architecture

Applied and Environmental Microbiology ◽

10.1128/aem.00637-11 ◽

2011 ◽

Vol 77 (15) ◽

pp. 5238-5246 ◽

Cited By ~ 207

Author(s):

Aamir Ghafoor ◽

Iain D. Hay ◽

Bernd H. A. Rehm

Keyword(s):

Pseudomonas Aeruginosa ◽

Biofilm Formation ◽

Laser Scanning ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Extracellular Dna ◽

Confocal Laser ◽

Content Type ◽

Biofilm Architecture

ABSTRACTPseudomonas aeruginosais an opportunistic human pathogen and has been established as a model organism to study bacterial biofilm formation. At least three exopolysaccharides (alginate, Psl, and Pel) contribute to the formation of biofilms in this organism. Here mutants deficient in the production of one or more of these polysaccharides were generated to investigate how these polymers interactively contribute to biofilm formation. Confocal laser scanning microscopy of biofilms formed in flow chambers showed that mutants deficient in alginate biosynthesis developed biofilms with a decreased proportion of viable cells than alginate-producing strains, indicating a role of alginate in viability of cells in biofilms. Alginate-deficient mutants showed enhanced extracellular DNA (eDNA)-containing surface structures impacting the biofilm architecture. PAO1 ΔpslAΔalg8overproduced Pel, and eDNA showing meshwork-like structures presumably based on an interaction between both polymers were observed. The formation of characteristic mushroom-like structures required both Psl and alginate, whereas Pel appeared to play a role in biofilm cell density and/or the compactness of the biofilm. Mutants producing only alginate, i.e., mutants deficient in both Psl and Pel production, lost their ability to form biofilms. A lack of Psl enhanced the production of Pel, and the absence of Pel enhanced the production of alginate. The function of Psl in attachment was independent of alginate and Pel. A 30% decrease in Psl promoter activity in the alginate-overproducing MucA-negative mutant PDO300 suggested inverse regulation of both biosynthesis operons. Overall, this study demonstrated that the various exopolysaccharides and eDNA interactively contribute to the biofilm architecture ofP. aeruginosa.

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Fabrication of Microstructured Surface Topologies for the Promotion of Marine Bacteria Biofilm

Micromachines ◽

10.3390/mi12080926 ◽

2021 ◽

Vol 12 (8) ◽

pp. 926

Author(s):

Ariadni Droumpali ◽

Jörg Hübner ◽

Lone Gram ◽

Rafael Taboryski

Keyword(s):

Marine Bacteria ◽

Biofilm Formation ◽

Laser Scanning ◽

Large Scale ◽

Spatial Organization ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Microstructured Surface ◽

Roseobacter Group

Several marine bacteria of the Roseobacter group can inhibit other microorganisms and are especially antagonistic when growing in biofilms. This aptitude to naturally compete with other bacteria can reduce the need for antibiotics in large-scale aquaculture units, provided that their culture can be promoted and controlled. Micropatterned surfaces may facilitate and promote the biofilm formation of species from the Roseobacter group, due to the increased contact between the cells and the surface material. Our research goal is to fabricate biofilm-optimal micropatterned surfaces and investigate the relevant length scales for surface topographies that can promote the growth and biofilm formation of the Roseobacter group of bacteria. In a preliminary study, silicon surfaces comprising arrays of pillars and pits with different periodicities, diameters, and depths were produced by UV lithography and deep reactive ion etching (DRIE) on polished silicon wafers. The resulting surface microscale topologies were characterized via optical profilometry and scanning electron microscopy (SEM). Screening of the bacterial biofilm on the patterned surfaces was performed using green fluorescent staining (SYBR green I) and confocal laser scanning microscopy (CLSM). Our results indicate that there is a correlation between the surface morphology and the spatial organization of the bacterial biofilm.

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The role of surface adhesion on the macroscopic wrinkling of biofilms

10.1101/2021.12.09.471895 ◽

2021 ◽

Author(s):

Steffen Geisel ◽

Eleonora Secchi ◽

Jan Vermant

Keyword(s):

Laser Scanning ◽

Three Dimensional ◽

Bacterial Biofilm ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Microfluidic Channels ◽

Channel Networks ◽

Biofilm Growth ◽

And Control

Biofilms, bacterial communities of cells encased by a self-produced matrix, exhibit a variety of three-dimensional structures. Specifically, channel networks formed within the bulk of the biofilm have been identified to play an important role in the colonies viability by promoting the transport of nutrients and chemicals. Here, we study channel formation and focus on the role of the adhesion of the biofilm matrix to the substrate in Pseudomonas aeruginosa biofilms grown under constant flow in microfluidic channels. We perform phase contrast and confocal laser scanning microscopy to examine the development of the biofilm structure as a function of the substrates surface energy. The formation of the wrinkles and folds is triggered by a mechanical buckling instability, controlled by biofilm growth rate and the film's adhesion to the substrate. The three-dimensional folding gives rise to hollow channels that rapidly increase the overall volume occupied by the biofilm and facilitate bacterial movement inside them. The experiments and analysis on mechanical instabilities for the relevant case of a bacterial biofilm grown during flow enable us to predict and control the biofilm morphology.

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