IU Indianapolis ScholarWorks :: Browsing by Subject "Biofilm"

Browsing by Subject "Biofilm"

Now showing 1 - 10 of 29

A novel Gardnerella, Prevotella, and Lactobacillus standard that improves accuracy in quantifying bacterial burden in vaginal microbial communities
(Frontiers Media, 2023-06-19) Elnaggar, Jacob H.; Ardizzone, Caleb M.; Cerca, Nuno; Toh, Evelyn; Łaniewski, Paweł; Lillis, Rebecca A.; Herbst-Kralovetz, Melissa M.; Quayle, Alison J.; Muzny, Christina A.; Taylor, Christopher M.; Microbiology and Immunology, School of Medicine
Bacterial vaginosis (BV) is the most common vaginal dysbiosis. In this condition, a polymicrobial biofilm develops on vaginal epithelial cells. Accurately quantifying the bacterial burden of the BV biofilm is necessary to further our understanding of BV pathogenesis. Historically, the standard for calculating total bacterial burden of the BV biofilm has been based on quantifying Escherichia coli 16S rRNA gene copy number. However, E. coli is improper for measuring the bacterial burden of this unique micro-environment. Here, we propose a novel qPCR standard to quantify bacterial burden in vaginal microbial communities, from an optimal state to a mature BV biofilm. These standards consist of different combinations of vaginal bacteria including three common BV-associated bacteria (BVAB) Gardnerella spp. (G), Prevotella spp. (P), and Fannyhessea spp. (F) and commensal Lactobacillus spp. (L) using the 16S rRNA gene (G:P:F:L, G:P:F, G:P:L and 1G:9L). We compared these standards to the traditional E. coli (E) reference standard using known quantities of mock vaginal communities and 16 vaginal samples from women. The E standard significantly underestimated the copy numbers of the mock communities, and this underestimation was significantly greater at lower copy numbers of these communities. The G:P:L standard was the most accurate across all mock communities and when compared to other mixed vaginal standards. Mixed vaginal standards were further validated with vaginal samples. This new G:P:L standard can be used in BV pathogenesis research to enhance reproducibility and reliability in quantitative measurements of BVAB, spanning from the optimal to non-optimal (including BV) vaginal microbiota.
A Prospective, Randomized, Controlled Study to Evaluate the Effectiveness of a Fabric-Based Wireless Electroceutical Dressing Compared to Standard-of-Care Treatment Against Acute Trauma and Burn Wound Biofilm Infection
(Mary Ann Liebert, 2024) Chan, Rodney K.; Nuutila, Kristo; Mathew-Steiner, Shomita S.; Diaz, Victoria; Anselmo, Kristin; Batchinsky, Maria; Carlsson, Anders; Ghosh, Nandini; Sen, Chandan K.; Roy, Sashwati; Surgery, School of Medicine
Objective: Despite advances in the use of topical and parenteral antimicrobial therapy and the practice of early tangential burn wound excision to manage bacterial load, 60% of the mortality from burns is attributed to bacterial biofilm infection. A low electric field (∼1 V) generated by the novel FDA-cleared wireless electroceutical dressing (WED) was previously shown to significantly prevent and disrupt burn biofilm infection in preclinical studies. Based on this observation, the purpose of this clinical trial was to evaluate the efficacy of the WED dressing powered by a silver–zinc electrocouple in the prevention and disruption of biofilm infection. Approach: A prospective, randomized, controlled, single-center clinical trial was performed to evaluate the efficacy of the WED compared with standard-of-care (SoC) dressing to treat biofilms. Burn wounds were randomized to receive either SoC or WED. Biopsies were collected on days 0 and 7 for histology, scanning electron microscopy (SEM) examination of biofilm, and for quantitative bacteriological analyses. Results: In total, 38 subjects were enrolled in the study. In 52% of the WED-treated wounds, little to no biofilm could be detected by SEM. WED significantly lowered or prevented increase of biofilm in all wounds compared with the pair-matched SoC-treated wounds. Innovation: WED is a simple, easy, and rapid method to protect the wound while also inhibiting infection. It is activated by a moist environment and the electrical field induces transient and micromolar amounts of superoxide anion radicals that will prevent bacterial growth. Conclusion: WED decreased biofilm infection better compared with SoC. The study was registered in clinicaltrials.gov as NCT04079998.
Analyses of the Effects of Arginine, Nicotine, Serotype and Collagen-Binding Proteins on Biofilm Development by 33 Strains of Streptococcus mutans
(Frontiers Media, 2021-11-25) Wagenknecht, Dawn R.; Gregory, Richard L.; Biomedical and Applied Sciences, School of Dentistry
Streptococcus mutans serotype k strains comprise <3% of oral isolates of S. mutans but are prominent in diseased cardiovascular (CV) tissue. Collagen binding protein (CBP) genes, cbm and cnm, are prevalent in serotype k strains and are associated with endothelial cell invasion. Nicotine increases biofilm formation by serotype c strains of S. mutans, but its effects on serotype k strains and strains with CBP are unknown. Saliva contains arginine which alters certain properties of the extracellular polysaccharides (EPS) in S. mutans biofilm. We examined whether nicotine and arginine affect sucrose-induced biofilm of S. mutans serotypes k (n = 23) and c (n = 10) strains with and without CBP genes. Biofilm mass, metabolism, bacterial proliferation, and EPS production were assessed. Nicotine increased biomass and metabolic activity (p < 0.0001); arginine alone had no effect. The presence of a CBP gene (either cbm or cnm) had a significant effect on biofilm production, but serotype did not. Nicotine increased bacterial proliferation and the effect was greater in CBP + strains compared to strains lacking CBP genes. Addition of arginine with nicotine decreased both bacterial mass and EPS compared to biofilm grown in nicotine alone. EPS production was greater in cnm + than cbm + strains (p < 0.0001). Given the findings of S. mutans in diseased CV tissue, a nicotine induced increase in biofilm production by CBP + strains may be a key link between tobacco use and CV diseases.
The antibacterial effect of a radiopaque double antibiotic paste against both an established multispecies and a single enterococcus faecalis biofilm
(2019) Haslam, Bryce S.; Spolnik, Kenneth J.; Ehrlich, Ygal; Gregory, Richard L.; Bringas, Josef; Warner, Ned A.
For regenerative endodontic procedures (REPs) to be successful an elimination of bacteria from the root canal system must be accomplished. Many different medicaments with antibacterial properties have been used to obtain complete disinfection. Double antibiotic paste (DAP) containing a mixture of ciprofloxacin and metronidazole has been shown to be a promising intracanal medicament. The addition of a radiopaque filler such as zirconium oxide to DAP may affect the antibacterial properties of DAP as well as allow precise placement and radiographic visualization of its position in the canal system. The aim of the proposed study was to evaluate the direct antibacterial properties of zirconium oxide radiopacifier combined with DAP (RoDAP) against a multispecies biofilm from a bacterial isolate from an infected immature tooth with a necrotic pulp and a known single species biofilm. 4x4 mm radicular dentin specimens (n = 112) obtained from human extracted teeth were used prepared and sterilized prior to use. A multispecies clinical bacterial isolate from an immature tooth with a necrotic pulp and a single species Enterococcus faecalis isolate were obtained. These bacterial isolates were used to inoculate dentin slabs and grown for 3 weeks. The dentin slabs were treated for 1 week with 1.0-mg/mL and 10- mg/mL RoDAP, 1.0-mg/mL DAP, and two placebo pastes consisting of methyl cellulose (MC) and methyl cellulose combined with zirconium oxide (RoMC), respectively, as well as two no-treatment controls. Following treatment, the grown biofilm was detached and spiral plated. The plated biofilm cells were cultured for 24 hours and each group examined using a colony counter to determine bacterial numbers (CFUs/mL). Data analysis, using a 5.0-percent significance level was conducted using one-way ANOVA followed by pair-wise group comparisons. Both 1.0-mg/mL and 10 mg/mL RoDAP demonstrated significant antibacterial effects against bacterial isolates from an immature tooth with a necrotic pulp as well as an E. faecalis isolate. The precise application of RoDAP confirmed radiographically with its direct antibacterial properties may be beneficial for intracanal disinfection during REPs.
Antibiotic Treatment of Pseudomonas aeruginosa Biofilms Stimulates Expression of mgtE, a Virulence Modulator
(2012-08-07) Redelman, Carly Virginia; Anderson, Gregory G.; Blazer-Yost, Bonnie.; Bauer, Margaret.
Pseudomonas aeruginosa is a gram negative opportunistic pathogen with the capacity to cause serious disease by forming biofilms, most notably in the lungs of cystic fibrosis (CF) patients. Biofilms are communities of microorganisms that adhere to a solid surface, undergo global regulatory changes, secrete exopolysaccharides, and are innately antibiotic resistant. Virulence modulation is an important tool utilized by P. aeruginosa to propagate infection and biofilm formation in the CF airway. Many different virulence modulatory pathways and proteins have been identified including the protein, MgtE. MgtE has recently been discovered and has been implicated in virulence modulation, as an isogeneic mutation of mgtE leads to increased cytotoxicity. To further elucidate the role of MgtE in P. aerugionsa infections, transcriptional and translational regulation of this protein following antibiotic treatment has been explored. I have demonstrated that mgtE is transcriptionally upregulated following antibiotic treatment of most of the twelve antibiotics tested utilizing RT-PCR and QRT-PCR. A novel model system was employed, which utilizes cystic fibrosis bronchial epithelial (CFBE) cells homozygous for the ΔF508 mutation for these studies. This model system allows P. aeruginosa biofilms to form on CFBE cells modeling the P. aeruginosa in the CF airway. Translational effects of antibiotic treatment on MgtE have been attempted via Western blotting and cytotoxicity assays. Furthermore, to explore the possibility that mgtE is interacting with a known regulatory pathway, a transposon-mutant library was utilized and the regulatory proteins, AlgR and NarX, among others have been identified as possibly interacting with MgtE. Lastly, an MgtE homologue from Staphylococcus aureus was utilized to further demonstrate the virulence modulatory effects of MgtE by demonstrating the expression of the homologue results in decreased cytotoxicity, exactly like expression of the native P. aeruginosa MgtE. This research explores a newly discovered protein that impacts cytotoxicity and biofilm formation and provides valuable information about P. aeruginosa virulence.
The antimicrobial efficacy of innovative 3D triple antibiotic paste-mimic tubular scaffold against actinomyces naeslundii
(2015) Azabi, Asma Abulqasem; Bottino, Marco C.; Gregory, Richard L.; Spolnik, Kenneth J.; Cook, Norman Blaine, 1954-; Chu, Tien-Min Gabriel
Background: Root canal disinfection is an essential requirement for the success of regenerative endodontics. Currently, the so-called triple antibiotic paste (TAP) is considered the standard of care. Notwithstanding the good antimicrobial capacity, the high concentration of TAP has shown significant toxicity to human cells, especially dental pulp stem cells. A novel drug release system, i.e., a triple antibiotic paste-mimic electrospun scaffold containing low concentrations of the antibiotics present in the TAP, has emerged as an effective and reliable alternative to fight root canal infections without potential toxic effects on dental stem cells, which are an integral part of the regenerative treatment. Objectives: The aim of this study was to determine the antimicrobial efficacy of an innovative three-dimensional (3D) triple antibiotic paste-mimic tubular scaffold against Actinomyces naeslundii biofilm formed inside human root canal dentinal tubules. Materials and methods: Pure polydioxanone (PDS) polymer solution and PDS loaded with metronidazole, ciprofloxacin and minocycline (35 wt.% of each antibiotic, 3D-TAP-mimic scaffold) were spun into 3D fibrous scaffolds. A. naeslundii (ATCC 43146) was centrifuged to induce biofilm formation inside human root canal dentinal tubules using a dentin slice model (1 mm thickness and 2.5 mm canal diameter). The infected dentin slices were exposed to the 3D-TAP-mimic scaffold, TAP solution (50 mg/mL of each antibiotic), and antibiotic-free PDS. Biofilm elimination was quantitatively and qualitatively analyzed by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), respectively. Results: A dense penetration of A. naeslundii biofilm was observed by CLSM throughout the dentinal tubules. 3D-TAP-mimic scaffold significantly reduced the percentage of viable bacteria compared with PDS (p <.05). TAP solution completely eliminated viable bacteria without differing from 3D-TAP-mimic scaffolds. SEM images showed results similar to CLSM. Conclusion: Collectively, the proposed tubular 3D-TAP-mimic scaffold holds significant clinical potential for root canal disinfection strategy prior to regenerative endodontics.
The ATP-Dependent Protease ClpP Inhibits Biofilm Formation by Regulating Agr and Cell Wall Hydrolase Sle1 in Staphylococcus aureus
(Frontiers, 2017-05-15) Liu, Qian; Wang, Xing; Qin, Juanxiu; Cheng, Sen; Yeo, Won-Sik; He, Lei; Ma, Xiaowei; Liu, Xiaoyun; Li, Min; Bae, Taeok; Microbiology and Immunology, School of Medicine
Biofilm causes hospital-associated infections on indwelling medical devices. In Staphylococcus aureus, Biofilm formation is controlled by intricately coordinated network of regulating systems, of which the ATP-dependent protease ClpP shows an inhibitory effect. Here, we demonstrate that the inhibitory effect of ClpP on biofilm formation is through Agr and the cell wall hydrolase Sle1. Biofilm formed by clpP mutant consists of proteins and extracellular DNA (eDNA). The increase of the protein was, at least in part, due to the reduced protease activity of the mutant, which was caused by the decreased activity of agr. On the other hand, the increase of eDNA was due to increased cell lysis caused by the higher level of Sle1. Indeed, as compared with wild type, the clpP mutant excreted an increased level of eDNA, and showed higher sensitivity to Triton-induced autolysis. The deletion of sle1 in the clpP mutant decreased the biofilm formation, the level of eDNA, and the Triton-induced autolysis to wild-type levels. Despite the increased biofilm formation capability, however, the clpP mutant showed significantly reduced virulence in a murine model of subcutaneous foreign body infection, indicating that the increased biofilm formation capability cannot compensate for the intrinsic functions of ClpP during infection.
Effect of a chlorhexidine-encapsulated nanotube modified pit-and-fissure sealant on oral biofilm
(J-STAGE, 2021-05) Feitosa, Sabrina; Carreiro, Adriana F. P.; Martins, Victor M.; Platt, Jeffrey A.; Duarte, Simone; Biomedical Sciences and Comprehensive Care, School of Dentistry
The purpose of this study was to characterize a chlorhexidine-encapsulated nanotube modified pit-and-fissure sealant for biofilm development prevention. HS (commercial control); HNT (HS+15wt%Halloysite®-clay-nanotube); CHX10% (HS+15wt% HNT-encapsulated with chlorhexidine 10%); and CHX20% (HS+15wt% HNT-encapsulated with CHX20%) were tested. Degree-of-conversion (DC%), Knoop hardness (KHN), and viscosity were analyzed. The ability of the sealant to wet the fissures was evaluated. Specimens were tested for zones of inhibition of microbial growth. S. mutans biofilm was tested by measuring recovered viability. Data were statistically analyzed (p<0.05). DC% was significantly higher for the HNT-CHX groups. For KHN, CHX10% presented a lower mean value than the other groups. Adding HNT resulted in higher viscosity values. The biofilm on CHX10% and CHX20% sealants presented remarkable CFU/mL reduction in comparison to the HS. The experimental material was able to reduce the biofilm development in S. mutans biofilm without compromising the sealant properties.
Effect of a Tea Polyphenol on Different Levels of Exposure of Nicotine and Tobacco Extract on Streptococcus mutans Biofilm Formation
(Frontiers Media, 2021-12-01) Taylor, Emily S.; Gomez, Grace F.; Moser, Elizabeth A. S.; Sanders, Brian J.; Gregory, Richard L.; Biomedical and Applied Sciences, School of Dentistry
Objective: The purpose of this study was to compare the effects of different levels of nicotine and tobacco extract exposure on Streptococcus mutans biofilm formation and the inhibitory effect of the polyphenol epigallocatechin-3 gallate (EGCG) found in green tea. This study addressed the results of biofilm assays with EGCG and varying relative concentrations of nicotine and tobacco extract consistent with primary, secondary and tertiary levels of smoking exposure. Primary smoking exposure to nicotine has been demonstrated to significantly increase biofilm formation, while EGCG has been demonstrated to reduce S. mutans biofilm formation. Methods: S. mutans was treated with varying levels of nicotine or cigarette smoke condensate (CSC) concentrations (0–32 mg/ml and 0–2 mg/ml, respectively) in Tryptic Soy broth supplemented with 1% sucrose for different lengths of time simulating primary, secondary and tertiary smoking exposure with and without 0.25 mg/ml EGCG. The amount of total growth and biofilm formed was determined using a spectrophotometric crystal violet dye staining assay. Results: For both nicotine and CSC, primary exposure displayed overall significantly less growth compared to secondary exposure. For nicotine, secondary exposure demonstrated significantly greater growth than tertiary exposure levels. Overall, significantly greater total bacterial growth and biofilm formation in the presence of nicotine and CSC was observed in the absence of EGCG than in the presence of EGCG. However, biofilm growth was not significantly different among different concentrations of CSC. Conclusion: The results of this study help illustrate that nicotine-induced S. mutans biofilm formation is reduced by the presence of EGCG. This provides further evidence of the potential beneficial properties of polyphenols.
Effect of Curcumin-loaded Photoactivatable Polymeric Nanoparticle on peri-implantitis-related biofilm
(2022) Tonon, Caroline Coradi; Panariello, Beatriz; Chorilli, Marlus; Spolidorio, Denise Madalena Palomari; Duarte, Simone; Biomedical and Applied Sciences, School of Dentistry
Curcumin has been used as a photosensitizer (PS) for antimicrobial photodynamic chemotherapy (PACT). However, its low solubility, instability and poor bioavailability are a challenge for its in vivo application. This study aimed to synthesize curcumin-loaded polymeric nanoparticles (curcumin-NP) and to determine their antimicrobial and cytotoxic effects. Nanoparticles (NP) were synthesized by the nanoprecipitation method using polyprolactone as a polymer. Curcumin-NP was characterized by particle size, polydispersity index and zeta potential, scanning electron microscopy and curcumin encapsulation efficiency (EE). Curcumin-NP was compared to free curcumin solubilized in 10% DMSO as photosensitizers for PACT in single and multi-species Porphyromonas gingivalis, Fusobacterium nucleatum and Streptococcus oralis biofilms. Chlorhexidine 0.12% (CHX) and ultrapure water were used as positive and negative controls, respectively. The cytotoxic effect of curcumin-NP was evaluated on human periodontal ligament fibroblast cells (HPLF). Data were analyzed by ANOVA (α=0.05). Curcumin-NP exhibited homogeneity and stability in solution, small particle size and 67.5% EE of curcumin. Curcumin-NP presented antibiofilm activity at 500 µg/ml when photoactivated. Curcumin-NP and curcumin with and without photoactivation were not cytotoxic to HPLF cells. Curcumin-NP has antimicrobial and antibiofilm properties, with better effects when associated with blue-light, being a promising therapy for preventing and treating peri-implant diseases.

Browsing by Subject "Biofilm"

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