Premium
Violet 405 nm light: A novel therapeutic agent against β‐lactam‐resistant Escherichia coli
Author(s) -
Rhodes Nathaniel L.R.,
de la Presa Martin,
Barneck Mitchell D.,
Poursaid Ahrash,
Firpo Matthew A.,
Langell John T.
Publication year - 2016
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.22457
Subject(s) - escherichia coli , bacteria , microbiology and biotechnology , sterilization (economics) , irradiance , antibacterial activity , antibiotics , ampicillin , biology , chemistry , gene , biochemistry , genetics , physics , quantum mechanics , monetary economics , economics , foreign exchange market , foreign exchange
Background and Objective Approximately 1.7 million patients are affected by hospital‐acquired infections every year in the United States. The increasing prevalence of multidrug‐resistant bacteria associated with these infections prompts the investigation of alternative sterilization and antibacterial therapies. One method currently under investigation is the antibacterial properties of visible light. This study examines the effect of a visible light therapy (VLT) on β‐lactam‐resistant Escherichia coli , a common non‐skin flora pathogen responsible for a large percentage of indwelling medical device‐associated clinical infection. Materials and Methods 405 nm light‐emitting diodes were used to treat varying concentrations of a common laboratory E. coli K‐12 strain transformed with the pCIG mammalian expression vector. This conferred ampicillin resistance via expression of the β‐lactamase gene. Bacteria were grown on sterile polystyrene Petri dishes plated with Luria‐Bertani broth. Images of bacterial growth colonies on plates were processed and analyzed using ImageJ. Irradiance levels between 2.89 ± 0.19 and 9.45 ± 0.63 mW cm −2 and radiant exposure levels between 5.60 ± 0.39 and 136.91 ± 4.06 J cm −2 were tested. Results VLT with variable irradiance and constant treatment time (120 minutes) demonstrated significant reduction ( P < 0.001) in E. coli between an irradiance of 2.89 mW cm −2 (81.70%) and 9.37 mW cm −2 (100.00%). Similar results were found with variable treatment time with constant irradiance. Log 10 reduction analysis produced between 1.98 ± 0.53 (60 minute treatment) and 6.27 ± 0.54 (250 minute treatment) log 10 reduction in bacterial concentration ( P < 0.001). Conclusions We have successfully demonstrated a significant bacterial reduction using high intensity 405 nm light. Illustrating the efficacy of this technology against a β‐lactam‐resistant E. coli is especially relevant to the need for novel methods of sterilization in healthcare settings. These results suggest that VLT using 405 nm light could be a suitable clinical option for eradication of β‐lactam‐resistant E. coli . Lasers Surg. Med. 48:311–317, 2016. © 2015 Wiley Periodicals, Inc. Visible light kills statistically significant concentrations of E. coli . Antibiotic‐resistant Gram‐negative bacteria exhibits sensitivity to 405 nm light. Greater than 6 log 10 reduction in β‐lactam‐resistant E. coli when treated with visible light therapy.