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Inhibition of Klebseilla pneumoniae by Visible and Near-IR Radiation
Authors: J. Stephen Guffey, William C. Payne, Jessica Greenway, Ben Buchanan, Carly M. Dodson, Kristoffer Lancaster
Number of views: 305
Abstract: We have studied the effect of blue light on Mycobacterium smegmatis, and the effects of combined blue and
infrared on Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans and found that inhibition can be
obtained. This research sought to determine the potential for visible and near-IR radiation to inhibit Klebseilla pneumoniae.
Additionally, the study sought to determine whether wavelength, dose or a combination of wavelength and dose could
produce a significant inhibitory effect. K. pneumoniae was tested due to its addition to the “urgent threat” list compiled by the
Centers for Disease Control. The organism was treated in vitro with 464nm, 850nm and a combined 464 & 850nm light
emitted from a supraluminous diode (SLD) array. Doses of 3, 10, 30, 45, 60 Joules per square centimeter (J/cm2) were used.
Colony counts were compared to untreated controls using a Repeated Measures ANOVA. One-way ANOVA with Tukey
HSD was used for post hoc analysis. The results revealed statistically significant inhibition of K. pneumoniae for wavelength,
dose and interaction of wavelength and dose (Main Effect F1,9 = 3971.89, p = 0.00; Interactive Effect F1,9 = 645.68, p = 0.00).
Post hoc analysis revealed that the combined 464 & 850nm wavelength at 45 and 60 J/cm2 were significantly effective and
different from the other treatment conditions. A maximum kill rate of 96.19% was achieved with the combination blue/IR
wavelength at 60 J/cm2
. We concluded that a combined visible and near-IR radiation at 45 and 60 J/cm2
is an effective
inhibitor of K. pneumoniae.