Characterization of blue light irradiation effects on pathogenic and nonpathogenic <i>Escherichia coli</i>

Abana, Courtney M.; Brannon, John R.; Ebbott, Rebecca A.; Dunigan, Taryn L.; Guckes, Kirsten R.; Fuseini, Hubaida; Powers, Jennifer G.; Rogers, Bridget R.; Hadjifrangiskou, Maria

doi:10.1002/mbo3.466

Cited by 26 publications

(34 citation statements)

References 104 publications

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“…However, Abana et al claimed that the effect of 455 nm is not completely bactericidal on E. coli but depends on the microorganism (pathogenic or non-pathogenic) and growth phase. They demonstrated that the stationary phase was more resistant compared to the exponential phase [45]. Based on our findings, blue light only had an impact on P. fluorescens biofilms under the harshest condition (100% I max ).…”

Section: Blue Lightsupporting

confidence: 60%

“…The number of photodynamic inactivation studies has greatly increased in recent years. These studies have mainly examined planktonic cells [38][39][40][41]43,[45][46][47][48][49][50][51][52], while few studies have taken bacterial biofilms into consideration [16,30,32,[50][51][52][53][54][55]. Since biofilms pose a major global healthcare problem, the impact of photodynamic inactivation on them is both crucial and innovative.…”

Section: Discussionmentioning

confidence: 99%

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Visible Light as an Antimicrobial Strategy for Inactivation of Pseudomonas fluorescens and Staphylococcus epidermidis Biofilms

et al. 2020

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The increase of antimicrobial resistance is challenging the scientific community to find solutions to eradicate bacteria, specifically biofilms. Light-Emitting Diodes (LED) represent an alternative way to tackle this problem in the presence of endogenous or exogenous photosensitizers. This work adds to a growing body of research on photodynamic inactivation using visible light against biofilms. Violet (400 nm), blue (420 nm), green (570 nm), yellow (584 nm) and red (698 nm) LEDs were used against Pseudomonas fluorescens and Staphylococcus epidermidis. Biofilms, grown on a polystyrene surface, were irradiated for 4 h. Different irradiance levels were investigated (2.5%, 25%, 50% and 100% of the maximum irradiance). Surviving cells were quantified and the inactivation kinetic parameters were estimated. Violet light could successfully inactivate P. fluorescens and S. epidermidis (up to 6.80 and 3.69 log10 reduction, respectively), while blue light was effective only against P. fluorescens (100% of maximum irradiance). Green, yellow and red irradiation neither increased nor reduced the biofilm cell density. This is the first research to test five different wavelengths (each with three intensities) in the visible spectrum against Gram-positive and Gram-negative biofilms. It provides a detailed study of the potential of visible light against biofilms of a different Gram-nature.

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Section: Blue Lightsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Visible Light as an Antimicrobial Strategy for Inactivation of Pseudomonas fluorescens and Staphylococcus epidermidis Biofilms

et al. 2020

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“…Abana et al delineated the effectiveness of aBL at 455 nm throughout different growth phases of E coli , i.e., log, transition, and early stationary phases (Abana et al, 2017). Five E coli strains belonging to different phylogenetic groups and in suspensions were studied.…”

Section: Efficacy Of Antimicrobial Blue Light Inactivation Of Pathmentioning

confidence: 99%

Antimicrobial blue light inactivation of pathogenic microbes: State of the art

Wang

et al. 2017

Drug Resistance Updates

223

192

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As an innovative non-antibiotic approach, antimicrobial blue light in the spectrum of 400–470 nm has demonstrated its intrinsic antimicrobial properties resulting from the presence of endogenous photosensitizing chromophores in pathogenic microbes and, subsequently, its promise as a counteracter of antibiotic resistance. Since we published our last review of antimicrobial blue light in 2012, there have been a substantial number of new studies reported in this area. Here we provide an updated overview of the findings from the new studies over the past 5 years, including the efficacy of antimicrobial blue light inactivation of different microbes, its mechanism of action, synergism of antimicrobial blue light with other angents, its effect on host cells and tissues, the potential development of resistance to antimicrobial blue light by microbes, and a novel interstitial delivery approach of antimicrobial blue light. The potential new applications of antimicrobial blue light are also discussed.

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“…A key limitation in the use of the popular ratiometric probe, pHluorin, is that the illumination wavelengths used to excite the fluorophore promote the well-known blue light effect-incident light at 405 nm has bactericidal effects on a variety of species [42][43][44][45][46]. This could interfere with pH measurements by affecting cell physiology [45,47]. Another problem is the need for multi-wavelength excitation setups, which can cost more and can limit measurements of rapid changes in the pH, especially if the excitation wavelength must be repeatedly alternated.…”

Section: Introductionmentioning

confidence: 99%

Protein expression-independent response of intensity-based pH-sensitive fluorophores in Escherichia coli

2020

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Fluorescent proteins that modulate their emission intensities when protonated serve as excellent probes of the cytosolic pH. Since the total fluorescence output fluctuates significantly due to variations in the fluorophore levels in cells, eliminating the dependence of the signal on protein concentration is crucial. This is typically accomplished with the aid of ratiometric fluorescent proteins such as pHluorin. However, pHluorin is excited by blue light, which can complicate pH measurements by adversely impacting bacterial physiology. Here, we characterized the response of intensity-based, pH-sensitive fluorescent proteins that excite at longer wavelengths where the blue light effect is diminished. The pH-response was interpreted in terms of an analytical model that assumed two emission states for each fluorophore: a low intensity protonated state and a high intensity deprotonated state. The model suggested a scaling to eliminate the dependence of the signal on the expression levels as well as on the illumination and photon-detection settings. Experiments successfully confirmed the scaling predictions. Thus, the internal pH can be readily determined with intensity-based fluorophores with appropriate calibrations irrespective of the fluorophore concentration and the signal acquisition setup. The framework developed in this work improves the robustness of intensity-based fluorophores for internal pH measurements in E. coli, potentially extending their applications.

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Characterization of blue light irradiation effects on pathogenic and nonpathogenic Escherichia coli

Cited by 26 publications

References 104 publications

Visible Light as an Antimicrobial Strategy for Inactivation of Pseudomonas fluorescens and Staphylococcus epidermidis Biofilms

Visible Light as an Antimicrobial Strategy for Inactivation of Pseudomonas fluorescens and Staphylococcus epidermidis Biofilms

Antimicrobial blue light inactivation of pathogenic microbes: State of the art

Protein expression-independent response of intensity-based pH-sensitive fluorophores in Escherichia coli

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