Dataset Information

Methylene Blue-Mediated Antimicrobial Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An In Vitro Study.

ABSTRACT:

Background/purpose

Some multidrug-resistant gram-negative bacteria as a global threat have been recently prioritized for research and development of new treatments. We studied the efficacy of methylene blue-mediated antimicrobial photodynamic therapy (MB-aPDT) for the reduction of extensively drug-resistant Acinetobacter baumannii (XDR-AB) and Pseudomonas aeruginosa (XDR-PS) and multidrug-resistant Klebsiella pneumoniae (MDR-KP) isolated in a university hospital setting in Thailand.

Method

Two isolates of each selected bacterium were collected, XDR-AB1 and AB2, XDR- PS1 and PS2, and MDR-KP1 and KP2. Three triplicate experiments using various MB concentrations alone, various red light fluences alone, as well as the selected non-toxic doses of MB and fluences of red light combined as MB-aPDT were applied on each selected isolate. The colonies were counted [colony forming units (CFU)/ml]. Estimation of the lethal treatment dose defined as reduction of > 2 log₁₀ in CFU/ml compared with untreated bacteria.

Result

There were generally negligible changes in the viable counts of the bacterial suspensions treated with all the MB concentrations (p > 0.05). In the second experiment with the only red light treatments, at fluences higher than 2 J/cm, reduction trend in viable counts across all the isolates was observed. Only for MDR-KP1, however, the lethal dose was achieved with the highest fluence of red light (80 J/cm). With the concentration of MB, 50 and 150 mg/L in the third experiment (MB-aPDT), the greater bacterial reduction was observed in all clinical isolates leading to their lethal viable cell reduction when escalating the light fluence to 80 J/cm.

Conclusions

MB-aPDT evidently killed the selected XDR and MDR-gram negative bacteria. In highly drug-resistant crisis era, MB-aPDT could be a promising option, particularly for local infections and infection complicating chronic wounds.

SUBMITTER: Songsantiphap C

PROVIDER: S-EPMC9283779 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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Publications

Methylene Blue-Mediated Antimicrobial Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An <i>In Vitro</i> Study.

Songsantiphap Chankiat C Vanichanan Jakapat J Chatsuwan Tanittha T Asawanonda Pravit P Boontaveeyuwat Einapak E

Frontiers in cellular and infection microbiology 20220701

<h4>Background/purpose</h4>Some multidrug-resistant gram-negative bacteria as a global threat have been recently prioritized for research and development of new treatments. We studied the efficacy of methylene blue-mediated antimicrobial photodynamic therapy (MB-aPDT) for the reduction of extensively drug-resistant <i>Acinetobacter baumannii</i> (XDR-AB) and <i>Pseudomonas aeruginosa</i> (XDR-PS) and multidrug-resistant <i>Klebsiella pneumoniae</i> (MDR-KP) isolated in a university hospital sett ...[more]

PMID: 35846758

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Project description:A promising alternative to antibiotics for treatment of Staphylococcus aureus infections is photodynamic inactivation (PDI), which employs a photosensitizer (PS) that produces cytotoxic reactive oxygen species (ROS) when exposed to molecular oxygen and antimicrobial blue light in the spectrum of 400-470 nm. Although the precise mechanistic basis of PDI has not been defined, the formation of ROS and free radicals that oxidize a number of cellular targets, including membrane lipids, damage to proteins and nucleic acids result in inactivation of essential cellular functions and subsequent cell death. Because PDI is non-selective and affects multiple cellular targets, development of resistance or tolerance to PDI has been considered to be unlikely and attempts to induce S. aureus resistance or tolerance upon repeated sub-lethal doses of PDI have not succeeded. However, multiple aspects of PDI suggest that development of tolerance is highly probable, in particular when PDI is used for treatment of infections where the environment at the infection site prevents penetration of PDI at a level sufficient to cause death of all bacteria and with tolerant phenotypes emerging from the surviving bacteria. In this study, we sought to identify the mechanisms that contribute to PDI tolerance in S. aureus. S. aureus HG003 and the isogenic HG003DmutSL strain with defects in DNA mismatch repair were used to evaluate the response of S. aureus and the roles of DNA mismatch repair and gene regulatory networks to repeated sublethal doses of PDI. Global transcriptome and genome analyses were used in an agnostic approach to identify the underlying transcriptional responses and genetic adaptations that occur as a result of repeated PDI and contribute to PDI tolerance. Our results reveal multiple metabolic, transport and cell wall biogenesis pathways that contribute to PDI tolerance, and a S. aureus regulatory gene likely responsible for the adaptive transcriptional response to PDI.

Project description:BackgroundCombination therapies comprising multiple methods, such as photodynamic therapy have been applied to be complements chemotherapy as they increase the therapeutic efficiency by enabling the intelligent drug delivery to target sites by exposing the photosensitizer to light and activating it in the tumor tissue. This study evaluated in vitro photodynamic therapy of methylene blue (MB)-loaded acetyl resistant starch (ARS) nanoparticles (NPs).MethodsARS was synthesized by the reaction between resistant starch (RS) and acetic anhydride. MB-loaded ARS NPs and ARS NPs were prepared by a single emulsion method. Synthesized ARS was measured by NMR. Prepared ARS NPs and MB-loaded ARS NPs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction, UV/Vis, and circular dichroism (CD). MB-loaded ARS NPs were treated in mouse colon cancer cells (CT-26) and they were treated under near-infrared (NIR) laser irradiation.ResultsSynthesis of ARS was confirmed by NMR and the degree of substitutions in the ARS was 7.1. The morphologies of ARS NPs observed by TEM were spherical shapes and the particle sizes of ARS NPs were 173.4 nm with a surface charge of - 17.24 mV. The d-spacing of ARS NPs was smaller than those of RS and the conformational changes of RS occurred by the formation of self-assembled polymeric NPs with induction of CD of the MB by chiral ARS NPs. The phototoxicity of CT-26 cells treated by MB-loaded ARS NPs dramatically decreased in a dose-dependent manner under NIR laser irradiation compared to free MB.ConclusionThis study demonstrated the ordered nanosized structures in the ARS NPs and conformational change from random coil structure of RS to alpha-helices one of ARS occurred and CD of the achiral MB was induced. The MB-loaded ARS NPs showed a higher generation of reactive oxygen species (ROS) in the CT-26 cells than free MB with the NIR laser irradiation and resulting in phototoxicity under irradiation.

Dataset Information

Methylene Blue-Mediated Antimicrobial Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An In Vitro Study.

Background/purpose

Method

Result

Conclusions

Publications

Methylene Blue-Mediated Antimicrobial Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An <i>In Vitro</i> Study.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Dataset Information

Methylene Blue-Mediated Antimicrobial ​Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant ​Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An In Vitro Study.

Background/purpose

Method

Result

Conclusions

Publications

Methylene Blue-Mediated Antimicrobial ​Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant ​Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An <i>In Vitro</i> Study.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Methylene Blue-Mediated Antimicrobial Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An In Vitro Study.

Methylene Blue-Mediated Antimicrobial Photodynamic Therapy Against Clinical Isolates of Extensively Drug Resistant Gram-Negative Bacteria Causing Nosocomial Infections in Thailand, An <i>In Vitro</i> Study.