Efficacy of a Topical Wound Agent Methanesulfonic Acid and Dimethylsulfoxide on In Vitro Biofilms

A topical desiccating wound agent containing methanesulfonic acid, dimethylsulfoxide and amorphous silica was evaluated in three in vitro models for its efficacy against biofilms produced by Pseudomonas aeruginosa (ATCC-15442) and Staphylococcus aureus (ATCC-6538). The in vitro biofilm models used were; the MBEC Assay®, Centre for Disease Control (CDC) Biofilm Reactor® and a Semi-solid biofilm model. A 30-s exposure of a topical wound desiccating agent was used in each model. A complete eradication of viable cells was demonstrated in all models for both strains (p < 0.0001). Imaging with scanning electron microscopy (SEM) was performed where possible. All three models demonstrated complete eradication of viable cells with a 30 s application of a topical wound desiccating agent.

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Impact of Daptomycin Dose Exposure Alone or in Combination with β-Lactams or Rifampin against Vancomycin-Resistant Enterococci in an In Vitro Biofilm Model

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02074-19 ◽

2020 ◽

Vol 64 (5) ◽

Cited By ~ 1

Author(s):

Seyedehameneh Jahanbakhsh ◽

Nivedita B. Singh ◽

Juwon Yim ◽

Razieh Kebriaei ◽

Jordan R. Smith ◽

...

Keyword(s):

Bactericidal Activity ◽

Enterococcus Faecium ◽

Biofilm Reactor ◽

Content Type ◽

Biofilm Model ◽

Vancomycin Resistant Enterococci ◽

Dosing Regimens ◽

Vancomycin Resistant ◽

Reactor Models

ABSTRACT Enterococcus faecium strains are commonly resistant to vancomycin and β-lactams. In addition, E. faecium often causes biofilm-associated infections and these infections are difficult to treat. In this context, we investigated the activity of dosing regimens using daptomycin (DAP) (8, 10, 12, and 14 mg/kg of body weight/day) alone and in combination with ceftaroline (CPT), ampicillin (AMP), ertapenem (ERT), and rifampin (RIF) against 2 clinical strains of biofilm-producing vancomycin-resistant Enterococcus faecium (VREfm), namely, strains S447 and HOU503, in an in vitro biofilm model. HOU503 harbors common LiaS and LiaR substitutions, whereas S447 lacks mutations associated with the LiaFSR pathway. MIC results demonstrated that both strains were susceptible to DAP and resistant to CPT, AMP, ERT, and RIF. The 168-h pharmacokinetic/pharmacodynamic (PK/PD) CDC biofilm reactor models (simulating human antibiotic exposures) were used with titanium and polyurethane coupons to evaluate the efficacy of antibiotic combinations. DAP 12 and 14 achieved bactericidal activity against S447 but lacked such effect against HOU503. Addition of ERT and RIF enhanced DAP activity, allowing DAP 8 and 10 plus ERT or RIF to produce bactericidal activity against both strains at 168 h. While DAP 8 and 10 plus CPT improved killing, they did not reach bactericidal reduction against S447. Combination of AMP, CPT, ERT, or RIF resulted in enhanced and bactericidal activity for DAP against HOU503 at 168 h. Our data provide further support for the use of combinations of DAP with AMP, ERT, CPT, and RIF in infections caused by biofilm producing VREfm. Further research involving DAP combinations against biofilm-producing enterococci is warranted.

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In Vitro Models to Study Influenza Virus and Staphylococcus aureus Super-Infection on a Molecular Level

Methods in Molecular Biology - Influenza Virus ◽

10.1007/978-1-4939-8678-1_18 ◽

2018 ◽

pp. 375-386

Author(s):

Christin Bruchhagen ◽

Andre van Krüchten ◽

Carolin Klemm ◽

Stephan Ludwig ◽

Christina Ehrhardt

Keyword(s):

Staphylococcus Aureus ◽

Influenza Virus ◽

Molecular Level ◽

In Vitro Models ◽

Super Infection ◽

And Staphylococcus Aureus

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An in vitro collagen perfusion wound biofilm model; with applications for antimicrobial studies and microbial metabolomics

BMC Microbiology ◽

10.1186/s12866-019-1682-5 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 3

Author(s):

Elisabeth A. Slade ◽

Robin M. S. Thorn ◽

Amber Young ◽

Darren M. Reynolds

Keyword(s):

Pseudomonas Aeruginosa ◽

Steady State ◽

Hydrogen Cyanide ◽

Solid Matrix ◽

Wound Fluid ◽

Biofilm Model ◽

Selected Ion Flow Tube ◽

Semi Solid

Abstract Background The majority of in vitro studies of medically relevant biofilms involve the development of biofilm on an inanimate solid surface. However, infection in vivo consists of biofilm growth on, or suspended within, the semi-solid matrix of the tissue, whereby current models do not effectively simulate the nature of the in vivo environment. This paper describes development of an in vitro method for culturing wound associated microorganisms in a system that combines a semi-solid collagen gel matrix with continuous flow of simulated wound fluid. This enables culture of wound associated reproducible steady state biofilms under conditions that more closely simulate the dynamic wound environment. To demonstrate the use of this model the antimicrobial kinetics of ceftazidime, against both mature and developing Pseudomonas aeruginosa biofilms, was assessed. In addition, we have shown the potential application of this model system for investigating microbial metabolomics by employing selected ion flow tube mass spectrometry (SIFT-MS) to monitor ammonia and hydrogen cyanide production by Pseudomonas aeruginosa biofilms in real-time. Results The collagen wound biofilm model facilitates growth of steady-state reproducible Pseudomonas aeruginosa biofilms under wound like conditions. A maximum biofilm density of 1010 cfu slide− 1 was achieved by 30 h of continuous culture and maintained throughout the remainder of the experiment. Treatment with ceftazidime at a clinically relevant dose resulted in a 1.2–1.6 log reduction in biofilm density at 72 h compared to untreated controls. Treatment resulted in loss of complex biofilm architecture and morphological changes to bacterial cells, visualised using confocal microscopy. When monitoring the biofilms using SIFT-MS, ammonia and hydrogen cyanide levels peaked at 12 h at 2273 ppb (±826.4) and 138 ppb (±49.1) respectively and were detectable throughout experimentation. Conclusions The collagen wound biofilm model has been developed to facilitate growth of reproducible biofilms under wound-like conditions. We have successfully used this method to: (1) evaluate antimicrobial efficacy and kinetics, clearly demonstrating the development of antimicrobial tolerance in biofilm cultures; (2) characterise volatile metabolite production by P. aeruginosa biofilms, demonstrating the potential use of this method in metabolomics studies.

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A Study on the Synbiotic Composition of Bifidobacterium bifidum and Fructans from Arctium lappa Roots and Helianthus tuberosus Tubers against Staphylococcus aureus

Microorganisms ◽

10.3390/microorganisms9050930 ◽

2021 ◽

Vol 9 (5) ◽

pp. 930

Author(s):

Svetlana A. Evdokimova ◽

Vera S. Nokhaeva ◽

Boris A. Karetkin ◽

Elena V. Guseva ◽

Natalia V. Khabibulina ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Jerusalem Artichoke ◽

Quantitative Model ◽

In Vitro Models ◽

Bifidobacterium Bifidum ◽

Arctium Lappa ◽

Suppression Effect ◽

Plant Sources ◽

And Staphylococcus Aureus

A number of mechanisms have been proposed explaining probiotics and prebiotics benefit human health, in particular, probiotics have a suppression effect on pathogen growth that can be enhanced with the introduction of prebiotics. In vitro models enhanced with computational biology can be useful for selecting a composition with prebiotics from new plant sources with the greatest synergism. Water extracts from burdock root and Jerusalem artichoke tubers were purified by ultrafiltration and activated charcoal and concentrated on a rotary evaporator. Fructans were precipitated with various concentrations of ethanol. Bifidobacterium bifidum 8 VKPM AC−2136 and Staphylococcus aureus ATCC 43300 strains were applied to estimate the synbiotic effect. The growth of bifidobacteria and staphylococci in monocultures and cocultures in broths with glucose, commercial prebiotics, as well as isolated fructans were studied. The minimum inhibitory concentrations (MICs) of lactic and acetic acids for the Staphylococcus strain were determined. A quantitative model joining the formation of organic acids by probiotics as antagonism factors and the MICs of pathogens (as the measure of their inhibition) was tested in cocultures and showed a high predictive value (R2 ≥ 0.86). The synbiotic factor obtained from the model was calculated based on the experimental data and obtained constants. Fructans precipitated with 20% ethanol and Bifidobacterium bifidum have the greater synergism against Staphylococcus.

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