Antimicrobial Blue Light Inactivation of Gram-Negative Pathogens in Biofilms: In Vitro and In Vivo Studies

Abstract

aBL has antimicrobial activity in biofilms ofA. baumannii and P. aeruginosa and is a potential therapeutic approach for biofilm-related infections.

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

“…Our group performed studies of aBL inactivation of P. aeruginosa and A. baumannii biofilms using bioluminescent strains (Wang et al, 2016). Biofilms were formed by incubating bacterial suspensions in 96-well microtiter plates for 24 to 72 h. Viability of bacterial cells in biofilms were quantified based on the bacterial luminescence.…”

“…P. aeruginosa (Dai et al, 2013b; Wang et al, 2016), A. baumannii (Wang et al, 2016; Zhang et al, 2014) and C. albicans (Zhang et al, 2016) were investigated by using fluorescence spectroscopy or HPLC analysis. All results implied the presence of endogenous porphyrins and/or flavins in the microbial cells.…”

“…Using in vivo normal mouse skin, our group evaluated the genotoxic effect of 415 nm aBL on skin cells using TUNEL assay (Wang et al, 2016). Immunofluorescence pictures of representative mouse skin before, 0 h, and 24 h after a single aBL exposure (540 J/cm 2 ), shown in Figure 6, revealed no presence of apoptotic cells in aBL-irradiated mouse skin up to 24 h after aBL exposure.…”

The antimicrobial effect of blue light: What are behind?

“…14,23,25,26,30,35 It was also observed that pathogenic microbes are less able to develop resistance to aBL than to conventional antibiotics. Our group recently performed several studies by exposing Pseudomonas aeruginosa, 25 Acinetobacter baumannii, 28 Candida albicans 27 or Escherichia coli (unpublished), to repeated cycles of sub-lethal aBL.…”

“…25,27,28 Other studies demonstrated that aBL did not cause significant damages to host cells and did not impair wound healing. 18,26,28,34,39,40 In this issue of Virulence, Fila et al 22 investigated the effectiveness of aBL inactivation of Pseudomonas aeruginosa using a panel of wide types and clinical strains, including multidrug-resistant and extensively drug-resistant strains. In agreement of previous studies, the authors found that aBL exerted significant antimicrobial effect on all Pseudomonas aeruginosa strains tested, resulting in 5.2-to 8-log 10 reduction of colony forming units (CFU).…”