Staphylococcus aureus growth delay after exposure to low fluencies of blue light (470 nm).

I D C Galo,B E De Lima,W G Dos Santos,R P Prado,A Braoios,T G Santos

doi:10.1590/1519-6984.226473

I D C Galo, B E De Lima + Show 4 more

Open Access

https://doi.org/10.1590/1519-6984.226473

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Abstract

Antibiotic resistance is one of the greatest challenges to treat bacterial infections worldwide, leading to increase in medical expenses, prolonged hospital stay and increased mortality. The use of blue light has been suggested as an innovative alternative to overcome this problem. In this study we analyzed the antibacterial effect of blue light using low emission parameters on Staphylococcus aureus cultures. In vitro bacterial cultures were used in two experimental approaches. The first approach included single or fractionated blue light application provided by LED emitters (470 nm), with the following fluencies: 16.29, 27.16 and 54.32 J/cm2. For the second approach a power LED (470 nm) was used to deliver 54.32 J/cm2 fractionated in 3 applications. Our results demonstrated that bacterial cultures exposed to fractionated blue light radiation exhibited significantly smaller sizes colonies than the control group after 24 h incubation, however the affected bacteria were able to adapt and continue to proliferate after prolonged incubation time. We could conclude that the hypothetical clinical use of low fluencies of blue light as an antibacterial treatment is risky, since its action is not definitive and proves to be ineffective at least for the strain used in this study.

Highlights

Introduction(Dai et al, 2012; Bumah et al, 2013; Meurer et al, 2019; Rupel et al, 2019)
It has been demonstrated that several bacterial species are able to develop resistance to pharmacological treatment due to inappropriate and longstanding use of antibiotic drugs 370 370/376(Dai et al, 2012; Bumah et al, 2013; Meurer et al, 2019; Rupel et al, 2019)
The verified inhibition pattern suggests a fluence-dependent of the blue light antibacterial action, with 54.32 J/cm2 the most effective fluence

Summary

Introduction

(Dai et al, 2012; Bumah et al, 2013; Meurer et al, 2019; Rupel et al, 2019). S. aureus growth delay by blue light exposure evolved capacity of developing resistance to antimicrobial drugs. It is an important etiological agent in skin wound contaminations, often evolving to generalized infections (Enwemeka et al, 2009; Bumah et al, 2013, 2015; Sousa et al, 2015; Freitas et al, 2018; Ferrer‐Espada et al, 2019; Rupel et al, 2019)

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