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

2018 ◽  
Vol 45 (4) ◽  
pp. 1399-1409 ◽  
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.

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

Biomedicines ◽  
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.

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

Scanning ◽  
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.

scholarly journals The vicK gene of Streptococcus mutans mediates its cariogenicity via exopolysaccharides metabolism

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Yalan Deng ◽  
Yingming Yang ◽  
Bin Zhang ◽  
Hong Chen ◽  
Yangyu Lu ◽  
...  
Keyword(s):  
Dental Caries ◽  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Single Species ◽  
Laser Scanning Microscopy ◽  
Gas Chromatography Mass Spectrometry ◽  
Extracellular Polysaccharides ◽  
Confocal Laser

AbstractStreptococcus mutans (S. mutans) is generally regarded as a major contributor to dental caries because of its ability to synthesize extracellular polysaccharides (EPS) that aid in the formation of plaque biofilm. The VicRKX system of S. mutans plays an important role in biofilm formation. The aim of this study was to investigate the effects of vicK gene on specific characteristics of EPS in S. mutans biofilm. We constructed single-species biofilms formed by different mutants of vicK gene. Production and distribution of EPS were detected through atomic force microscopy, scanning electron microscopy and confocal laser scanning microscopy. Microcosmic structures of EPS were analyzed by gel permeation chromatography and gas chromatography-mass spectrometry. Cariogenicity of the vicK mutant was assessed in a specific pathogen-free rat model. Transcriptional levels of cariogenicity-associated genes were confirmed by quantitative real-time polymerase chain reaction. The results showed that deletion of vicK gene suppressed biofilm formation as well as EPS production, and EPS were synthesized mostly around the cells. Molecular weight and monosaccharide components underwent evident alterations. Biofilms formed in vivo were sparse and contributed a decreased degree of caries. Moreover, expressional levels of genes related to EPS synthesis were down-regulated, except for gtfB. Our report demonstrates that vicK gene enhances biofilm formation and subsequent caries development. And this may due to its regulations on EPS metabolism, like synthesis or microcosmic features of EPS. This study suggests that vicK gene and EPS can be considered as promising targets to modulate dental caries.

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

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.

scholarly journals Protozoan impact on bacterial biofilm formation

2010 ◽  
Vol 47 (1) ◽  
pp. 3-10 ◽  
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.

scholarly journals Effect of Novel Antibacterial Composites on Bacterial Biofilms

2020 ◽  
Vol 11 (3) ◽  
pp. 55 ◽  
Author(s):  
Rayan B. Yaghmoor ◽  
Wendy Xia ◽  
Paul Ashley ◽  
Elaine Allan ◽  
Anne M. Young
Keyword(s):  
Laser Scanning ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Surface Layers ◽  
Composite Surface ◽  
Biofilm Thickness ◽  
Diffusion Controlled ◽  
Restoration Failure

Continuing cariogenic bacterial growth demineralizing dentine beneath a composite filling is the most common cause of tooth restoration failure. Novel composites with antibacterial polylysine (PLS) (0, 4, 6, or 8 wt%) in its filler phase were therefore produced. Remineralising monocalcium phosphate was also included at double the PLS weight. Antibacterial studies involved set composite disc placement in 1% sucrose-supplemented broth containing Streptococcus mutans (UA159). Relative surface bacterial biofilm mass (n = 4) after 24 h was determined by crystal violet-binding. Live/dead bacteria and biofilm thickness (n = 3) were assessed using confocal laser scanning microscopy (CLSM). To understand results and model possible in vivo benefits, cumulative PLS release from discs into water (n = 3) was determined by a ninhydrin assay. Results showed biofilm mass and thickness decreased linearly by 28% and 33%, respectively, upon increasing PLS from 0% to 8%. With 4, 6, and 8 wt% PLS, respectively, biofilm dead bacterial percentages and PLS release at 24 h were 20%, 60%, and 80% and 85, 163, and 241 μg/disc. Furthermore, initial PLS release was proportional to the square root of time and levelled after 1, 2, and 3 months at 13%, 28%, and 42%. This suggested diffusion controlled release from water-exposed composite surface layers of 65, 140, and 210 μm thickness, respectively. In conclusion, increasing PLS release initially in any gaps under the restoration to kill residual bacteria or longer-term following composite/tooth interface damage might help prevent recurrent caries.

scholarly journals Role of Exopolysaccharides in Pseudomonas aeruginosa Biofilm Formation and Architecture

2011 ◽  
Vol 77 (15) ◽  
pp. 5238-5246 ◽  
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.

scholarly journals R-Thanatin Inhibits Growth and Biofilm Formation of Methicillin-Resistant Staphylococcus epidermidisIn VivoandIn Vitro

2013 ◽  
Vol 57 (10) ◽  
pp. 5045-5052 ◽  
Author(s):  
Zheng Hou ◽  
Fei Da ◽  
Baohui Liu ◽  
Xiaoyan Xue ◽  
Xiuli Xu ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Drug Candidate ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACTStaphylococcus epidermidisis one of the most frequent causes of device-associated infections, because it is known to cause biofilms that grow on catheters or other surgical implants. The persistent increasing resistance ofS. epidermidisand other coagulase-negative staphylococci (CoNS) has driven the need for newer antibacterial agents with innovative therapeutic strategies. Thanatin is reported to display potent antibiotic activities, especially against extended-spectrum-beta-lactamase-producingEscherichia coli. The present study aimed to investigate whether a shorter derivative peptide (R-thanatin) could be used as a novel antibacterial agent. We found that R-thanatin was highly potentin vitroagainst coagulase-negative staphylococci, such asS. epidermidis,S. haemolyticus, andS. hominis, and inhibited biofilm formation at subinhibitory concentrations. Properties of little toxicity to human red blood cells (hRBCs) and human umbilical vein endothelial cells, a low incidence of resistance, and relatively high stability in plasma were confirmed. Excellentin vivoprotective effects were also observed using a methicillin-resistantS. epidermidis(MRSE)-induced urinary tract infection rat model. Electron microscopy and confocal laser-scanning microscopy analyses suggested that R-thanatin disturbed cell division of MRSE severely, which might be the reason for inhibition of MRSE growth. These findings indicate that R-thanatin is active against the growth and biofilm formation of MRSEin vitroandin vivo. R-thanatin might be considered as a specific drug candidate for treating CoNS infections.

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

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1783
Author(s):  
Alessandra Cataldo Cataldo Russomando ◽  
Ronit Vogt Vogt Sionov ◽  
Michael Friedman ◽  
Irith Gati ◽  
Ron Eliashar ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Bacterial Biofilm ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Disc Diffusion ◽  
Biofilm Growth ◽  
Disc Diffusion Assay ◽  
Diffusion Assay

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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