Altering the viscoelastic properties of mucus-grown Pseudomonas aeruginosa biofilms affects antibiotic susceptibility

Rouillard, Kaitlyn R.; Markovetz, Matthew R.; Kissner, William J.; Boone, William L.; Plott, Lucas M.; Hill, David B.

doi:10.1016/j.bioflm.2023.100104

Cited by 9 publications

(35 citation statements)

References 59 publications

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“…52,53 Akin to dispersal, reducing the viscoelastic moduli of biofilms, thus making the biofilms more susceptible to flow and deformation, should aid in the eradication of bacteria. 54 Upon treatment with CD-EDA 7 /NO, the G' of tobramycin-susceptible biofilms was reduced by 36− 66%, regardless of the dose (Figure 3A). Similarly, concentrations of Alg-PAPA-DPTA/NO greater than 1 mg mL −1 led to a 67−80% reduction in G'.…”

Section: ■ Results and Discussionmentioning

confidence: 97%

“…Control biofilms exhibited average elastic ( G ’) and viscous moduli ( G ”) of 0.38 and 0.09 Pa, respectively. The G ”-to- G ’ ratio of 0.23 indicates that these biofilms exhibit viscoelastic characteristics of a cross-linked gel, stemming from the production of EPS in the biofilm matrix that serves as a protective barrier. , Akin to dispersal, reducing the viscoelastic moduli of biofilms, thus making the biofilms more susceptible to flow and deformation, should aid in the eradication of bacteria . Upon treatment with CD-EDA 7 /NO, the G ’ of tobramycin-susceptible biofilms was reduced by 36–66%, regardless of the dose (Figure A).…”

Section: Resultsmentioning

confidence: 99%

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Biofilm Dispersal, Reduced Viscoelasticity, and Antibiotic Sensitization via Nitric Oxide-Releasing Biopolymers

et al. 2023

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Compared to planktonic bacteria, biofilms are notoriously difficult to eradicate due to their inherent protection against the immune response and antimicrobial agents. Inducing biofilm dispersal to improve susceptibility to antibiotics is an attractive therapeutic avenue for eradicating biofilms. Nitric oxide (NO), an endogenous antibacterial agent, has previously been shown to induce biofilm dispersal, but with limited understanding of the effects of NO-release properties. Herein, the antibiofilm effects of five promising NO-releasing biopolymer candidates were studied by assessing dispersal, changes in biofilm viscoelasticity, and increased sensitization to tobramycin after treatment with NO. A threshold level of NO was needed to achieve biofilm dispersal, with longer-releasing systems requiring lower concentrations. The most positively charged NO-release systems (from the presence of primary amines) led to the greatest reduction in viscoelasticity of Pseudomonas aeruginosa biofilms. Co-treatment of tobramycin with the NO-releasing biopolymer greatly decreased the dose of tobramycin required to eradicate tobramycin-susceptible and -resistant biofilms in both cellular and tissue models.

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Section: ■ Results and Discussionmentioning

confidence: 97%

Section: Resultsmentioning

confidence: 99%

Biofilm Dispersal, Reduced Viscoelasticity, and Antibiotic Sensitization via Nitric Oxide-Releasing Biopolymers

et al. 2023

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“…While results indicate that C. difficile does not break down mucins sufficiently to detect decreased molecular weights, the observed increase in viscosity could reflect additional ways C. difficile responds to mucus. Biofilm formation within mucus can lead to increased viscosity, as observed with Pseudomonas aeruginosa 48 . We therefore examined the impact of mucus on C. difficile biofilm formation in vitro .…”

Section: Resultsmentioning

confidence: 99%

“…S3A). We applied particle tracking microrheology (PTMR) to measure the viscosity C. difficile-and mock-inoculated mucus, using a Gaussian mixture model to distinguish watery (less viscous) vs. mucoid (more viscous) fractions of mucus 28,[46][47][48] . After 24 hours, mucus containing C. difficile had more mucoid signal relative to the mock-inoculated control, as indicated by increased detection of microbeads within the mucoid vs. watery fraction (Fig.…”

Section: Difficile Biofilm Formation May Increase Viscosity Of Ex Viv...mentioning

confidence: 99%

Clostridioides difficile-mucus interactions encompass shifts in gene expression, metabolism, and biofilm formation

Furtado,

Plott,

Markovetz

et al. 2024

Preprint

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In a healthy colon, the stratified mucus layer serves as a crucial innate immune barrier to protect the epithelium from microbes. Mucins are complex glycoproteins that serve as a nutrient source for resident microflora and can be exploited by pathogens. We aimed to understand how the intestinal pathogen,Clostridioides diffiicile, independently uses or manipulates mucus to its benefit, without contributions from members of the microbiota. Using a 2-D primary human intestinal epithelial cell model to generate physiologic mucus, we assessedC. difficile-mucus interactions through growth assays, RNA-Seq, biophysical characterization of mucus, and contextualized metabolic modeling. We found that host-derived mucus promotesC. difficilegrowth bothin vitroand in an infection model. RNA-Seq revealed significant upregulation of genes related to central metabolism in response to mucus, including genes involved in sugar uptake, the Wood-Ljungdahl pathway, and the glycine cleavage system. In addition, we identified differential expression of genes related to sensing and transcriptional control. Analysis of mutants with deletions in highly upregulated genes reflected the complexity ofC. difficile-mucus interactions, with potential interplay between sensing and growth. Mucus also stimulated biofilm formation in vitro, which may in turn alter viscoelastic properties of mucus. Context-specific metabolic modeling confirmed differential metabolism and predicted importance of enzymes related to serine and glycine catabolism with mucus. Subsequent growth experiments supported these findings, indicating mucus is an important source of serine. Our results better define responses ofC. difficileto human gastrointestinal mucus and highlight a flexibility in metabolism that may influence pathogenesis.

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“…(23,24) For example, tobramycin exhibits reduced antibiotic action in sputum and does not disrupt the viscoelastic properties of P. aeruginosa biofilms grown in airway mucus. (21,24,25) It has been proposed that disruption of the biofilm matrix may potentiate antibiotic efficacy and improve the potential for clearance, (25,26) which has previously been observed with the use of alginate oligosaccharides. (27)(28)(29)(30)(31) Enzymatic degradation of DNA in the matrix via DNase has also demonstrated synergistic bactericidal action when used in combination with antibiotics.…”

Section: Introductionmentioning

confidence: 99%

Combination Treatment to Improve Mucociliary Transport ofPseudomonas aeruginosaBiofilms

Rouillard

Esther

Plott

et al. 2023

Preprint

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People with muco-obstructive pulmonary diseases such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD) often have acute or chronic respiratory infections that are difficult to treat due in part to the accumulation of hyperconcentrated mucus within the airway. Mucus accumulation and obstruction promote chronic inflammation and infection and reduce therapeutic efficacy. Bacterial aggregates in the form of biofilms exhibit increased resistance to mechanical stressors from the immune response (e.g., phagocytosis) and chemical treatments including antibiotics. Herein, combination treatments designed to disrupt the mechanical properties of biofilms and potentiate antibiotic efficacy are investigated against mucus-grown Pseudomonas aeruginosa biofilms and optimized to 1) alter biofilm viscoelastic properties, 2) increase mucociliary transport rates, and 3) reduce bacterial viability. A disulfide bond reducing agent (tris(2-carboxyethyl)phosphine, TCEP), a surfactant (NP40), a biopolymer (hyaluronic acid, HA), a DNA degradation enzyme (DNase), and an antibiotic (tobramycin) are tested in various combinations to maximize biofilm disruption. The viscoelastic properties of biofilms are quantified with particle tracking microrheology and transport rates are quantified in a mucociliary transport device comprised of fully differentiated primary human bronchial epithelial cells. The combination of the NP40 with hyaluronic acid and tobramycin was the most effective at increasing mucociliary transport rates, decreasing the viscoelastic properties of mucus, and reducing bacterial viability. Multimechanistic targeting of biofilm infections may ultimately result in improved clinical outcomes, and the results of this study may be translated into future in vivo infection models.

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Altering the viscoelastic properties of mucus-grown Pseudomonas aeruginosa biofilms affects antibiotic susceptibility

Cited by 9 publications

References 59 publications

Biofilm Dispersal, Reduced Viscoelasticity, and Antibiotic Sensitization via Nitric Oxide-Releasing Biopolymers

Biofilm Dispersal, Reduced Viscoelasticity, and Antibiotic Sensitization via Nitric Oxide-Releasing Biopolymers

Clostridioides difficile-mucus interactions encompass shifts in gene expression, metabolism, and biofilm formation

Combination Treatment to Improve Mucociliary Transport ofPseudomonas aeruginosaBiofilms

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