Different susceptibility of spores and hyphae of Trichophyton rubrum to methylene blue mediated photodynamic treatment in vitro

Abstract

Trichophyton rubrum (T ruburm) is the most common dermatophyte worldwide. It is responsible for the majority of dermatomycosis, including tinea manus and pedis, tinea cruris, tinea corporis and tinea unguium. 1 With the increases of immunocompromised population and broad-spectrum antibiotics abuse, the incidence of dermatomycosis has also been on the rise in recent years. 2 Although superficial fungal infections are rarely life-threatening, they can cause damage to the skin appearance and normal function, and

In vitro evaluation of photodynamic activity of methylene blue against Trichophyton verrucosum azole‐susceptible and ‐resistant strains

“…Previous studies have demonstrated that methylene blue with light emission diode is effective and safe, with positive response rates of~85% to 100% [44]. The effective action of such therapy has also been shown in the treatment of dermatophytoses [32,33].…”

“…Guffey et al [32] found that methylene blue at concentration equal to 0.64 μg/mL (in the original work the concentration defined as 2 μmol/L), the T. rubrum were completely killed by 625 nm red light at the dose of 60 J/cm 2 . Furthermore, Li et al [33] revealed that methylene blue at concentration equal to 0.625 μg/mL and with 20 J/cm 2 energy of 635 nm light showed significant inhibitory effect toward T. rubrum cells. These results are approximately consistent with our study.…”

“…Subsequently, a LED spotlight (Lifotronic, Shenzen, China) with a light power of 58 mW/cm 2 and peak wavelength of 635 nm was used to deliver the light energy at various dose, that is, 1, 5, 10, 20, 40, 60, 80 and 100 J/ cm 2 , corresponding to the exposure time of 17, 88, 175, 350, 701, 1050, 1400 and 1750 second, respectively. Photodynamic reaction was performed in Eppendorf tube, which has been proved to be not a barrier to the penetration of red light [33]. The irradiation was carried out directly at a distance of 5 cm from the light source.…”

“…Currently, photodynamic therapy has been revealed to be an efficient therapeutic solution against a variety of fungi, including antropophilic, that is, Trichophyton rubrum, and zoophilic, that is, Trichophyton mentagrophytes dermatophytes [30,31]. Several studies have also demonstrated that methylene blue mediated photodynamic therapy has the definite better inhibitory effect on fungi, which solution was tested in detail against T. rubrum [32,33]. Methylene blue is a photosensitiser that has a strong absorption band in the red light wavelength range, presents low toxicity toward human and animal cells, and is relatively inexpensive [34].…”

“…A significant side effect related with the use of such therapy is a cytotoxic effect on neutrophils [35]. As far as we know the inhibitory effect of photodynamic therapy with methylene blue was tested in detail for T. rubrum [32,33]. There are no similar data in the literature in case of zoophilic dermatophytes.…”