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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Inactivation kinetics and lethal dose analysis of antimicrobial blue light and photodynamic therapy

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Author(s):
Sabino, Caetano P. [1, 2] ; Wainwright, Mark [3] ; dos Anjos, Carolina [4] ; Sellera, Fabio P. [4] ; Baptista, Mauricio S. [5] ; Lincopan, Nilton [6, 1] ; Ribeiro, Martha S. [7]
Total Authors: 7
Affiliation:
[1] Univ Sao Paulo, Sch Pharmaceut Sci, Dept Clin Anal, Sao Paulo, SP - Brazil
[2] BioLambda, Sci & Commercial LTD, Sao Paulo, SP - Brazil
[3] Liverpool John Moores Univ, Sch Pharm & Biomol Sci, Liverpool, Merseyside - England
[4] Univ Sao Paulo, Sch Vet Med & Anim Sci, Dept Internal Med, Sao Paulo, SP - Brazil
[5] Univ Sao Paulo, Inst Chem, Dept Biochem, Sao Paulo, SP - Brazil
[6] Univ Sao Paulo, Inst Biomed Sci, Dept Microbiol, Sao Paulo, SP - Brazil
[7] Natl Commiss Nucl Energy, Ctr Lasers & Applicat, Nucl & Energy Res Inst, Sao Paulo, SP - Brazil
Total Affiliations: 7
Document type: Journal article
Source: Photodiagnosis and Photodynamic Therapy; v. 28, p. 186-191, DEC 2019.
Web of Science Citations: 1
Abstract

Background: Antimicrobial Photodynamic therapy (A-PDT) has been used to treat infections. Currently, microbial inactivation data is reported presenting survival fraction averages and standard errors as discrete points instead of a continuous curve of inactivation kinetics. Standardization of this approach would allow clinical protocols to be introduced globally, instead of the piecemeal situation which currently applies. Methods: To this end, we used a power-law function to fit inactivation kinetics and directly report values of lethal doses (LD) and a tolerance factor (T) that informs if inactivation rate varies along the irradiation procedure. A deduced formula was also tested to predict LB for any given survival fraction value. We analyzed the photoantimicrobial effect caused by red light activation of methylene blue (MB-APDT) and by blue light (BL) activation of endogenous microbial pigments against 5 clinically relevant pathogens. Results: Following MB- APDT, Escherichia coli and Staphylococcus aureus cells become increasingly more tolerant to inactivation along the irradiation process (T < 1). Klebsiella pneumoniae presents opposite behavior, i.e., more inactivation is observed towards the end of the process (T > 1). P. aeruginosa and Candida albicans present constant inactivation rate (T(similar to)1). In contrast, all bacterial species presented similar behavior during inactivation caused by BL, i.e., continuously becoming more sensitive to blue light exposure (T > 1). Conclusion: The power-law function successfully fit all experimental data. Our proposed method precisely predicted LD and T values. We expect that these analytical models may contribute to more standardized methods for comparisons of photodynamic inactivation efficiencies. (AU)

FAPESP's process: 17/22406-0 - Development of a smart clinical equipment for phototherapies with automatic dosimetry calibration and on demand payment
Grantee:Caetano Padial Sabino
Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
FAPESP's process: 13/07937-8 - Redoxome - Redox Processes in Biomedicine
Grantee:Ohara Augusto
Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 16/08593-9 - Pan-Resistome of beta-lactamase (KPC-2, CTX-M-8, CTX-M-15)-producing Klebsiella pneumoniae and Escherichia coli isolates endemic in Brazil
Grantee:Nilton Erbet Lincopan Huenuman
Support Opportunities: Regular Research Grants