A biofilm growth protocol and the design of a magnetic field exposure setup to be used in the study of magnetic fields as a means of controlling bacterial biofilms

McLeod, Bruce R.; Sandvik, Elizabeth L.

doi:10.1002/bem.20529

Cited by 12 publications

(7 citation statements)

References 22 publications

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“…Organisms, such as Pseudomonas aeruginosa, are difficult to treat using antibiotics (30). Changes in the antibiotic susceptibility of Pseudomonas aeruginosa biofilm have been observed in response to changes in weak magnetic fields (31,32). In another well‐controlled trial, low‐intensity millimeter waves were effective at accelerating wound clearance when infected with a microflora containing mixed agent species (33,34).…”

Section: Discussionmentioning

confidence: 99%

Bacterial Bioluminescence, Bioelectromagnetics and Function

Pooley

2010

Photochem & Photobiology

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The biological functions of light emission in bacterial bioluminescence are not always obvious, especially if the bacteria are in a free-living mode. Experimental evidence suggests that light emission confers benefit to the bacteria themselves such as through photoreactivation and involves as much as 20% of cell energy metabolism. A theoretical model shows if the effect is mediated solely by light then cells should be luminescent at both high and low cell densities, therefore raising doubt over the photoreactivation hypothesis and suggesting that another cofactor is involved. It has been postulated that bioelectromagnetics may be involved in biological processes and be involved with coordinated activity in quorate cells. The cell densities associated with autoinduction coincide with a large change in coupling efficiency in the millimeter and submillimeter spectral region. In this paper it is suggested that one function of bioluminescence is as a pump, involving millimeter and submillimeter wave coupling that is of benefit to the quorum. This may be related to the observation that millimeter wave radiation exposure has been reported to induce changes in DNA conformation and possibly gene expression. Agents that change DNA conformation in bioluminescent bacteria can cause increases in light emission. This work may have implications for electromagnetic fields as quorum-quenching agents.

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Section: Discussionmentioning

confidence: 99%

Bacterial Bioluminescence, Bioelectromagnetics and Function

Pooley

2010

Photochem & Photobiology

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“…Isolates were grown on TSA plates incubated at 37 °C for 24 h and then suspended in normal saline to reach a concentration equivalent to a 0.5 McFarland. The in vitro model consisted of a previously described CDC biofilm reactor (CBR) model (BioSurfaces Technologies, Bozeman, MT, USA), which we modified to run PK/PD, simulating human PK to evaluate the in vitro activity of antimicrobials [ 11 , 17 , 18 ]. Briefly, a 40-h biofilm conditioning phase was performed prior to drug therapy initiation and consisted of a 24 h incubation at 37 °C in 1% gSTSB inoculated with the specified organism, followed by 16 h of a continuous flow with 1/10th gSTSB performed with peristaltic pumps (Masterflex ® ; Cole-Parmer Instrument Company, Chicago, IL, USA).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of High-Dose Daptomycin Versus Vancomycin Alone or Combined with Clarithromycin or Rifampin Against Staphylococcus aureus and S. epidermidis in a Novel In Vitro PK/PD Model of Bacterial Biofilm

et al. 2014

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IntroductionMedical device infections are associated with significant morbidity and mortality. These difficult-to-treat infections often result in antibiotic failure and resistance. Combination therapy is often required, however, the most optimal combination is unknown. We evaluated the in vitro activity of daptomycin (DAP) or vancomycin (VAN) alone and in combination with rifampin (RIF) or clarithromycin (CLA) against strains of Staphylococcus aureus and S. epidermidis grown in biofilm on 3 prosthetic device materials.MethodsOne methicillin-resistant S. aureus (MRSA R5266), one heteroresistant vancomycin-intermediate S. aureus (hVISA R3640), and one methicillin-resistant S. epidermidis (MRSE R461) strain was evaluated in a CDC biofilm reactor with titanium, Teflon®, and steel coupons. Regimens simulated included DAP 10 mg/kg/day, and VAN 1 g q12h alone or in combination with RIF 600 mg q24h or CLA 250 mg q12h. Additional regimens including DAP 12 mg/kg/day or VAN ± RIF 450 mg q12h were evaluated against the hVISA strain.ResultsDAP + RIF or VAN + RIF demonstrated enhanced activity against R3640 in embedded biofilm (EB) cells in all materials versus DAP or VAN alone (P ≤ 0.040). Only DAP + RIF demonstrated sustained bactericidal activity (≥3.80 log10 CFU/cm2 reduction from baseline) against EB and planktonic cells of R5266 and EB cells of R461 in all 3 materials. Of interest, CLA did not appear to enhance DAP or VAN killing activities, and the addition of RIF prevented the emergence of resistance to DAP or VAN in all organisms.ConclusionUsing an in vitro bacterial biofilm model containing three common prosthetic device materials, DAP + RIF and VAN + RIF were the most effective regimens. DAP + RIF displayed the greatest activity and represents a promising combination to evaluate for treatment of biofilm-associated staphylococcal infections.Electronic supplementary materialThe online version of this article (doi:10.1007/s40121-014-0055-5) contains supplementary material, which is available to authorized users.

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“…We based our protocol for biofilm growth upon the methods previously published by Donlan et al and McLeod and Sandvik (14,23). Briefly, a CDC biofilm reactor (CBR) model (BioSurfaces Technologies, Bozeman, MT) was set up with 24 polycarbonate coupons inserted into eight rods (3 coupons per rod).…”

Section: Methodsmentioning

confidence: 99%

Activities of High-Dose Daptomycin, Vancomycin, and Moxifloxacin Alone or in Combination with Clarithromycin or Rifampin in a NovelIn VitroModel ofStaphylococcus aureusBiofilm

Parra-Ruiz

Vidaillac

Rose

et al. 2010

Antimicrob Agents Chemother

116

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Biofilm formation is an important virulence factor that allows bacteria to resist host responses and antibacterial agents. The aim of the study was to assess the in vitro activities of several antimicrobials alone or in combination against two Staphylococcus aureus isolates in a novel pharmacokinetic/pharmacodynamic (PK/PD) model of biofilm for 3 days. One methicillin-susceptible S. aureus strain (SH1000) and one methicillin-resistant S. aureus strain (N315) were evaluated in a modified biofilm reactor with polystyrene coupons. Simulated regimens included vancomycin (VAN) plus rifampin (RIF), moxifloxacin (MOX), and high doses (10 mg/kg of body weight/day) of daptomycin (DAP) alone or combined with RIF or clarithromycin (CLA). Against viable planktonic bacteria (PB) and biofilm-embedded bacteria (BB) of SH1000, neither DAP nor MOX alone was bactericidal. In contrast, the combination of DAP or MOX with CLA significantly increased the activity of the two agents against both PB and BB (P < 0.01), and DAP plus CLA reached the limit of detection at 72 h. Against PB of N315, DAP alone briefly achieved bactericidal activity at 24 h, whereas sustained bactericidal activity was observed at 32 h with VAN plus RIF. Overall, only a minimal reduction was observed with both regimens against BB (<2.8 log 10 CFU/ml). Finally, the combination of DAP and RIF was bactericidal against both PB and BB, achieving the limit of detection at 72 h. In conclusion, we developed a novel in vitro PK/PD model to assess the activities of antimicrobials against mature bacterial biofilm. Combinations of DAP or MOX with CLA were the most effective regimens and may represent promising options to treat persistent infections caused by S. aureus biofilms.

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A biofilm growth protocol and the design of a magnetic field exposure setup to be used in the study of magnetic fields as a means of controlling bacterial biofilms

Cited by 12 publications

References 22 publications

Bacterial Bioluminescence, Bioelectromagnetics and Function

Bacterial Bioluminescence, Bioelectromagnetics and Function

Evaluation of High-Dose Daptomycin Versus Vancomycin Alone or Combined with Clarithromycin or Rifampin Against Staphylococcus aureus and S. epidermidis in a Novel In Vitro PK/PD Model of Bacterial Biofilm

Activities of High-Dose Daptomycin, Vancomycin, and Moxifloxacin Alone or in Combination with Clarithromycin or Rifampin in a NovelIn VitroModel ofStaphylococcus aureusBiofilm

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