New Insights into the Bacterial Targets of Antimicrobial Blue Light
Antimicrobial-drug development is facing increased scrutiny following the worldwide antibiotic crisis. Scientists across the world have recognized the urgent need for new antimicrobial therapies. , ABSTRACT Antimicrobial blue light (aBL) offers efficacy and safety in treating infections. However, the bacterial targets for aBL are still poorly understood and may be dependent on bacterial species. Here, we investigated the biological targets of bacterial killing by aBL (λ = 410 nm) on three pathogens: Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa . Initially, we evaluated the killing kinetics of bacteria exposed to aBL and used this information to calculate the lethal doses (LD) responsible for killing 90 and 99.9% of bacteria. We also quantified endogenous porphyrins and assessed their spatial distribution. We then quantified and suppressed reactive oxygen species (ROS) production in bacteria to investigate their role in bacterial killing by aBL. We also assessed aBL-induced DNA damage, protein carbonylation, lipid peroxidation, and membrane permeability in bacteria. Our data showed that P. aeruginosa was more susceptible to aBL (LD 99.9 = 54.7 J/cm 2 ) relative to S. aureus (LD 99.9 = 158.9 J/cm 2 ) and E. coli (LD 99.9 = 195 J/cm 2 ). P. aeruginosa exhibited the highest concentration of endogenous porphyrins and level of ROS production relative to the other species. However, unlike other species, DNA degradation was not observed in P. aeruginosa . Sublethal doses of blue light (textlessLD 90 ) could damage the cell membrane in Gram-negative species but not in S. aureus . In all bacteria, oxidative damage to bacterial DNA (except P. aeruginosa ), proteins, and lipids occurred after high aBL exposures (textgreaterLD 99.9 ). We conclude that the primary targets of aBL depend on the species, which are probably driven by variable antioxidant and DNA-repair mechanisms. IMPORTANCE Antimicrobial-drug development is facing increased scrutiny following the worldwide antibiotic crisis. Scientists across the world have recognized the urgent need for new antimicrobial therapies. In this sense, antimicrobial blue light (aBL) is a promising option due to its antimicrobial properties. Although aBL can damage different cell structures, the targets responsible for bacterial inactivation have still not been completely established and require further exploration. In our study, we conducted a thorough investigation to identify the possible aBL targets and gain insights into the bactericidal effects of aBL on three relevant pathogens: Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa . This research not only adds new content to blue light studies but opens new perspectives to antimicrobial applications.
Citação
@online{anjos,_carolina2023,
author = {Anjos, Carolina, Dos and Leon G. , Leanse and Martha S. ,
Ribeiro and Fábio P. , Sellera and Milena , Dropa and Victor E. ,
Arana-Chavez and Nilton , Lincopan and Maurício S. , Baptista and
Fabio C. , Pogliani and Tianhong , Dai and Caetano P. , Sabino},
title = {New Insights into the Bacterial Targets of Antimicrobial Blue
Light},
volume = {11},
number = {2},
date = {2023-04-13},
doi = {10.1128/spectrum.02833-22},
langid = {pt-BR},
abstract = {Antimicrobial-drug development is facing increased
scrutiny following the worldwide antibiotic crisis. Scientists
across the world have recognized the urgent need for new
antimicrobial therapies. , ABSTRACT Antimicrobial blue light (aBL)
offers efficacy and safety in treating infections. However, the
bacterial targets for aBL are still poorly understood and may be
dependent on bacterial species. Here, we investigated the biological
targets of bacterial killing by aBL (λ = 410 nm) on three pathogens:
Staphylococcus aureus , Escherichia coli , and Pseudomonas
aeruginosa . Initially, we evaluated the killing kinetics of
bacteria exposed to aBL and used this information to calculate the
lethal doses (LD) responsible for killing 90 and 99.9\% of bacteria.
We also quantified endogenous porphyrins and assessed their spatial
distribution. We then quantified and suppressed reactive oxygen
species (ROS) production in bacteria to investigate their role in
bacterial killing by aBL. We also assessed aBL-induced DNA damage,
protein carbonylation, lipid peroxidation, and membrane permeability
in bacteria. Our data showed that P. aeruginosa was more susceptible
to aBL (LD 99.9 = 54.7 J/cm 2 ) relative to S. aureus (LD 99.9 =
158.9 J/cm 2 ) and E. coli (LD 99.9 = 195 J/cm 2 ). P. aeruginosa
exhibited the highest concentration of endogenous porphyrins and
level of ROS production relative to the other species. However,
unlike other species, DNA degradation was not observed in P.
aeruginosa . Sublethal doses of blue light (textlessLD 90 ) could
damage the cell membrane in Gram-negative species but not in S.
aureus . In all bacteria, oxidative damage to bacterial DNA (except
P. aeruginosa ), proteins, and lipids occurred after high aBL
exposures (textgreaterLD 99.9 ). We conclude that the primary
targets of aBL depend on the species, which are probably driven by
variable antioxidant and DNA-repair mechanisms. IMPORTANCE
Antimicrobial-drug development is facing increased scrutiny
following the worldwide antibiotic crisis. Scientists across the
world have recognized the urgent need for new antimicrobial
therapies. In this sense, antimicrobial blue light (aBL) is a
promising option due to its antimicrobial properties. Although aBL
can damage different cell structures, the targets responsible for
bacterial inactivation have still not been completely established
and require further exploration. In our study, we conducted a
thorough investigation to identify the possible aBL targets and gain
insights into the bactericidal effects of aBL on three relevant
pathogens: Staphylococcus aureus , Escherichia coli , and
Pseudomonas aeruginosa . This research not only adds new content to
blue light studies but opens new perspectives to antimicrobial
applications.}
}