PURPOSE To evaluate in vitro the antibacterial effect of diode laser light of wavelength 650 nm, in association with the photosensitive substance toluidine blue, on the bacteria in infected skin ulcers. METHODS Samples were collected by means of swabs containing a medium for transporting infected material from skin ulcers. The material was inoculated into culturing medium containing azide blo...

This work reports the photophysical and biological evaluation of five cationic porphyrins as photosensitizers (PS) for the photodynamic inactivation (PDI) of Penicillium chrysogenum conidia. Two different cationic porphyrin groups were synthesized from 5,10,15,20-tetrakis(4-pyridyl)porphyrin and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin. The photostability and singlet oxygen generation st...

OBJECTIVES Efforts to control tuberculosis (TB) have been hampered by the emergence of multiple-drug resistant strains, necessitating pursuit of alternative approaches to the current antibiotic-based treatments. Herein, we explore the feasibility of photodynamic inactivation (PDI) of mycobacteria. METHODS In vitro PDI studies employing Mycobacterium smegmatis as a surrogate for Mycobacterium ...

Photodynamic inactivation of Staphylococcus aureus planktonic and biofilm cells by a phtotosensitizer, merocyanine 540 (MC 540), was investigated. For the planktonic experiments, MC 540 binding efficiency to bacterial cells was found to increase with both increasing MC 540 concentration and increasing incubation time, but the binding became saturated following 10 min of incubation. The antimicr...

This study evaluated the in vitro susceptibility of C. albicans, C. dubliniensis, C. tropicalis and C. krusei to photodynamic therapy (PDT) induced by Photogem(®)and light emitted diode (LED). Suspensions of each Candida strain were treated with three photosensitizer (PS) concentrations (10, 25 and 50 mg/L) and exposed to 18, 25.5 and 37.5 J/cm(2) LED light fluences (λ ~ 455 nm). Control suspen...

Introduction: Staphylococcus aureus is a gram positive bacteria responsible by localized and systemic infections. The bacterial resistance to antibiotics is a huge problem and a challenge for the development of new therapeutic modalities [1]. The photodynamic inactivation of microorganisms (PDI) is a promising technique to fight localized infections based on a association of a photosensitizer (...

Spore formation is a sophisticated mechanism by which some bacteria survive conditions of stress and starvation by producing a multilayered protective capsule enclosing their condensed DNA. Spores are highly resistant to damage by heat, radiation, and commonly employed antibacterial agents. Previously, spores have also been shown to be resistant to photodynamic inactivation using dyes and light...

[Ru(II)(bpy)(2)(dppn)](2+) (bpy = 2,2'-bipyridine, dppn = 4,5,9,16-tetraazadibenzo[a,c]naphthacene) was found to be able to photoinactivate Gram-negative Escherichia coli efficiently, showing the potential of transition-metal complexes as photosensitizers in the field of photodynamic antimicrobial chemotherapy (PACT).