In vitro augmented photodynamic bactericidal activity of tetracycline and chitosan against Clostridium difficile KCTC5009 in the planktonic cultures

Choi, SungSook; Lee, HaeKyung; Yu, Jin; Chae, Hiun-Suk

doi:10.1016/j.jphotobiol.2015.09.003

Cited by 16 publications

(17 citation statements)

References 26 publications

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“…PDT is a method widely used in dermatology and periodontics, less frequently in ophthalmology, gastroenterology, or other medicine branches [21][22][23][24]. This method is also successfully used against gram-positive and gram-negative bacteria in in vitro studies [25][26][27][28][29][30][31]. However, it should be underlined that there are only a few reports describing the use of aPDT in urological infection [13,14].…”

Section: Discussionmentioning

confidence: 99%

Photodynamic enhancement of the activity of antibiotics used in urinary tract infections

et al. 2019

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Photodynamic therapy (PDT) has been proven to kill different microbial cells. However, to our knowledge, none of the available reports describes the modulatory effect of this therapy on the antibacterial activity of antibiotics against Escherichia coli rods being the main causative agent of urinary tract infections (UTIs). Therefore, the aim of our study was to verify if the PDT can enhance the antibacterial activity of antibiotics recommended in the treatment of UTIs. An attempt to determine the optimal conditions of PDT to enhance the bactericidal activity of ciprofloxacin, amikacin, and colistin has been made. In order to find the optimal antimicrobial conditions, the efficacy of four protocols associated with the use of different energy doses (70 and 120 J/ cm 2 ) and chlorin e6 (Ce6) concentrations (50 and 100 μg/mL) has been verified. The antibacterial effect of combined PDT and antibiotics was assessed by the time-kill assay. The best results were achieved for Ce6 at a concentration of 100 μg/mL and the energy dose 120 J/cm 2 for bacterial suspensions treated with ciprofloxacin. Taken together, our results showed that PDT using Ce6 improves the antibacterial activity of antibiotics effectively inhibiting bacterial growth and being promising in the elimination of bacterial UTIs in humans.

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Section: Discussionmentioning

confidence: 99%

Photodynamic enhancement of the activity of antibiotics used in urinary tract infections

et al. 2019

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“…Endogenous porphyrins were also used in eradication of Clostridium difficile which is an etiological agent of pseudomembranous colitis and is responsible for opportunistic infections in intensive care units, which are mainly caused by the eradication of natural flora as a result of antibiotic administration (Musher et al, 2013 ; De Sordi et al, 2015 ). Choi et al ( 2015 ) proved that application of aPDI in combination with tetracycline (0.5 mg/ml) gave a 2 log 10 increased reduction in viable count after 5 min of irradiation and 3 log 10 after 10 min of light exposure. In addition, this effect could be further enhanced (4 log 10 greater than the count reduction in the control group) when chitosan was applied (Choi et al, 2015 ).…”

Section: Antimicrobial Photodynamic Inactivation Combined With Antimimentioning

confidence: 99%

“…Choi et al ( 2015 ) proved that application of aPDI in combination with tetracycline (0.5 mg/ml) gave a 2 log 10 increased reduction in viable count after 5 min of irradiation and 3 log 10 after 10 min of light exposure. In addition, this effect could be further enhanced (4 log 10 greater than the count reduction in the control group) when chitosan was applied (Choi et al, 2015 ). The application of aPDI in combination with tetracycline (1.0 mg/ml) or chloramphenicol reduced the number of viable counts for C. difficile by 7 log 10 more than UVA monotherapy.…”

Section: Antimicrobial Photodynamic Inactivation Combined With Antimimentioning

confidence: 99%

Combined Antimicrobial Activity of Photodynamic Inactivation and Antimicrobials–State of the Art

Woźniak

Grinholc

2018

Front. Microbiol.

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Antimicrobial photodynamic inactivation (aPDI) is a promising tool for the eradication of life-threatening pathogens with different profiles of resistance. This study presents the state-of-the-art published studies that have been dedicated to analyzing the bactericidal effects of combining aPDI and routinely applied antibiotics in in vitro (using biofilm and planktonic cultures) and in vivo experiments. Furthermore, the current paper reviews the methodology used to obtain the published data that describes the synergy between these antimicrobial approaches. The authors are convinced that even though the combined efficacy of aPDI and antimicrobials could be investigated with the wide range of methods, the use of a unified experimental methodology that is in agreement with antimicrobial susceptibility testing (AST) is required to investigate possible synergistic cooperation between aPDI and antimicrobials. Conclusions concerning the possible synergistic activity between the two treatments can be drawn only when appropriate assays are employed. It must be noticed that some of the described papers were just aimed at determination if combined treatments exert enhanced antibacterial outcome, without following the standard methodology to evaluate the synergistic effect, but in most of them (18 out of 27) authors indicated the existence of synergy between described antibacterial approaches. In general, the increase in bacterial inactivation was observed when both therapies were used in combination.

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“…The first report that tetracyclines could act as antibacterial PS was published as long ago as 1987 by Martin [ 8 ]. Since then there have only been two more reports about carrying out aPDI with tetracyclines [ 9 , 10 ]. Tetracyclines function by inhibiting bacterial ribosomal protein synthesis [ 11 ], and are generally considered to be bacteriostatic rather than bactericidal, although this has been questioned [ 12 ].…”

Section: Introductionmentioning

confidence: 99%

Tetracyclines function as dual-action light-activated antibiotics

Huang

et al. 2018

PLoS ONE

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Antimicrobial photodynamic inactivation (aPDI) employs photosensitizing dyes activated by visible light to produce reactive oxygen species. aPDI is independent of the antibiotic resistance status of the target cells, and is thought unlikely to produce resistance itself. Among many PS that have been investigated, tetracyclines occupy a unique niche. They are potentially dual-action compounds that can both kill bacteria under illumination, and prevent bacterial regrowth by inhibiting ribosomes. Tetracycline antibiotics are regarded as bacteriostatic rather than bactericidal. Doxycycline (DOTC) is excited best by UVA light (365 nm) while demeclocycline (DMCT) can be efficiently activated by blue light (415 nm) as well as UVA. Both compounds were able to eradicate Gram-positive (methicillin-resistant Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria (>6 log(10) steps of killing) at concentrations (10–50μM) and fluences (10-20J/cm2). In contrast to methylene blue, MB plus red light, tetracyclines photoinactivated bacteria in rich growth medium. When ~3 logs of bacteria were killed with DMCT/DOTC+light and the surviving cells were added to growth medium, further bacterial killing was observed, while the same experiment with MB allowed complete regrowth. MIC studies were carried out either in the dark or exposed to 0.5mW/cm2 blue light. Up to three extra steps (8-fold) increased antibiotic activity was found with light compared to dark, with MRSA and tetracycline-resistant strains of E. coli. Tetracyclines can accumulate in bacterial ribosomes, where they could be photoactivated with blue/UVA light producing microbial killing via ROS generation.

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In vitro augmented photodynamic bactericidal activity of tetracycline and chitosan against Clostridium difficile KCTC5009 in the planktonic cultures

Cited by 16 publications

References 26 publications

Photodynamic enhancement of the activity of antibiotics used in urinary tract infections

Photodynamic enhancement of the activity of antibiotics used in urinary tract infections

Combined Antimicrobial Activity of Photodynamic Inactivation and Antimicrobials–State of the Art

Tetracyclines function as dual-action light-activated antibiotics

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