In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent

Zolfaghari, Parjam; Packer, S; Singer, Mervyn; Nair, Sean P.; Bennett, J.E.; Street, Cale N.; Wilson, Michael

doi:10.1186/1471-2180-9-27

Cited by 177 publications

(125 citation statements)

References 29 publications

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“…25,26 Much is already known about the photodynamic inactivation of microorganisms: both antibiotic-sensitive and -resistant strains can be successfully photoinactivated, and there is the additional advantage that repeated photosensitization of bacterial cells does not induce a selection of resistant strains. [27][28][29][30] In our previous study, we investigated the photodynamic activity of a new photosensitive (sinoporphyrin sodium [DVDMS]). We observed that light-activated DVDMS enhanced intracellular ROS levels, which significantly induced cell death and markedly damaged S. aureus.…”

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confidence: 99%

Photodynamic antimicrobial chemotherapy for <em>Staphylococcus aureus</em> and multidrug-resistant bacterial burn infection in vitro and in vivo

Mai¹,

Gao²,

Li³

et al. 2017

IJN

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Background and objectives Antibiotic resistance has emerged as one of the most important determinants of outcome in patients with serious infections, along with the virulence of the underlying pathogen. Photodynamic antimicrobial chemotherapy (PACT) has been proposed as an alternative approach for the inactivation of bacteria. This study aims to evaluate the antibacterial effect of sinoporphyrin sodium (DVDMS)-mediated PACT on Staphylococcus aureus and multidrug resistant S. aureus in vitro and in vivo. Materials and methods Bacteria were incubated with DVDMS and exposed to treatment with light. After PACT treatment, colony-forming units were counted to estimate the bactericidal effect. Intracellular reactive oxygen-species production was detected by flow cytometry. Flow cytometry and fluorescence-microscopy detection of bacterial cell-membrane permeability. Enzyme-linked immunosorbent assays were used to determine expression of VEGF, TGFβ 1 , TNFα, IL6, and bFGF factors in burn infection. Results DVDMS-PACT effectively killed bacterial proliferation. Intracellular ROS levels were enhanced obviously in the PACT-treatment group. SYTO 9 and propidium iodide staining showed a decrease in the ratio of green:red fluorescence intensity in the PACT-treatment group in comparison to the control group. Enzyme-linked immunosorbent-assay results revealed that in the healing process, the expression of bFGF, TGFβ 1 , and VEGF in the treatment group were higher than in the control group, which inhibited inflammation-factor secretion. In addition, skin-tissue bacteria were reduced after treatment. Conclusion These results indicate that DVDMS-PACT presents significant bactericidal activity and promotes wound healing after burn infections.

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confidence: 99%

Photodynamic antimicrobial chemotherapy for <em>Staphylococcus aureus</em> and multidrug-resistant bacterial burn infection in vitro and in vivo

Mai¹,

Gao²,

Li³

et al. 2017

IJN

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“…Zolfaghari et al 17 evaluated the in vivo effect of PDT in mice with excisional and superficial skin wounds inoculated with a suspension of MRSA. The wounds were treated with 0.3 µM MB and irradiated with 360 J/cm² of diode laser light for 30 min.…”

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confidence: 99%

Effect of photodynamic therapy on clinical isolates of Staphylococcus spp

et al. 2011

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Staphylococcus spp. are opportunistic microorganisms known for their capacity to develop resistance against antimicrobial agents. The objective of this study was to evaluate the effect of photodynamic therapy (PDT) on 20 Staphylococcus strains isolated from the human oral cavity, including S. aureus, S. schleiferi, S. epidermidis, S. capitis, S. haemolyticus, and S. lentus. A suspension of each Staphylococcus strain (10 6 cells/ mL) was submitted to PDT using methylene blue and a low power laser. The isolated effects of methylene blue, laser treatment and ciprofloxacin were also evaluated. After the experimental treatments, 0.1 mL aliquots of the suspensions were seeded onto BHI agar for determination of the number of colony-forming units (CFU/mL). The results were analyzed by analysis of variance and Tukey's test (p ≤ 0.05). The mean reduction in bacterial counts of the strains submitted to PDT ranged from 4.89 to 6.83 CFU (log 10 )/mL, with the observation of a decreasing susceptibility to treatment of S. schleiferi, S. haemolyticus, S. epidermidis, S. capitis, S. aureus, and S. lentus. The results showed that PDT was effective in reducing the number of viable cells of all clinical Staphylococcus isolates studied.

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“…We have to take into account that photoinactivation is able to eradicate microorganisms without discriminating resistant isolates, both planktonic and biofilm species. This is in concert with the potential of localized photooxidative stress to inactivate virulence factors 134,135 and virulence determinants [136][137][138] in the absence of any documented conventional resistance mechanism. The possibility of active efflux seems to be related with some but not all the molecular classes of PSs although improved delivery methods may overcome this barrier.…”

Section: Biofilm Eradicationmentioning

confidence: 96%