Antimicrobial Photodynamic Therapy associated with long term success in endodontic treatment with separated instruments: A case report.

This paper describes a case with a 5- year follow-up of Antimicrobial Photodynamic Therapy (aPDT) associated with long-term success in endodontic treatment in a tooth with separated instruments. The patient presented with a tooth exhibiting a periapical lesion, slight swelling, and severe pain. A radiograph revealed the presence of two separated files in the middle and apical thirds of the mesial root on a lower first molar. Attempts at bypassing were not successful. In the mesial root, instrumentation was limited to the coronal ends of the separated instruments. The apical patency could not be achieved due to the blockage of the separated files. aPDT was performed in two visits, at a 660-nm wavelength and 100 mW of power, for 90 s to a total energy of 9.0 Joules. Methylene blue solution was used as photosensitizer at concentration of 0005%. A 300-µm light diffusor was coupled to the diode laser and was inserted into the root canal 2 mm short of WL, where it was set to allow better diffusion of light. Each root canal was sealed with gutta-percha by warm vertical compaction and Pulp Canal Sealer™. After 5 years of follow-up, clear evidence of remineralization of the radiolucency and bone healing was observed. This case report suggests that the addition of aPDT to conventional endodontic treatment improved microbial disinfection leading to a successful long-term outcome.

Photodynamic therapy as a new approach to Trichomonas vaginalis inactivation.

The emergence of nitroimidazole resistant isolates has been an aggravating factor in the treatment of trichomoniasis, the most common non-viral sexually transmitted disease in the world. This highlights the importance of new technologies that are safe, effective, and have minor side effects or resistance. Hence, we evaluated the effectiveness of photodynamic therapy on the inactivation of Trichomonas vaginalis in vitro. We used methylene blue as a photosensitizing substance, and a light-emitting diode (LED) for irradiation of metronidazole sensitive and resistant strains. Our results showed that only the presence of light did not interfere with parasite growth; however, methylene blue isolated or associated with light inhibited 31.78% ±â€¯7.18 and 80.21% ±â€¯7.11 of the sensitive strain, respectively, and 31.17% ±â€¯4.23 and 91.13% ±â€¯2.31 of the resistant strain, respectively. The high trichomonicidal activity of the photodynamic therapy, associated with low cost and ease of application, signalize its great therapeutic potential not only when conventional treatment fails, but also routinely in women with trichomoniasis.

Use of Surgical Laser for Excision of a Neurofibroma Associated With Neurofibromatosis Type-1.

Introduction: Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder that affects approximately 1/3500 individuals. Various bone manifestations and peripheral nerves neoplastic lesions associated with NF1 are seen in the jaws. Several oral manifestations may occur in this disorder; therefore the dentist's knowledge and multidisciplinary management of these patients are extremely important. Case Presentation: In the present article, we present the use of a high-power surgical laser to excise a neurofibroma in a patient with several intraoral manifestations associated with NF1. Conclusion: The use of diode laser (808 nm) for excision biopsy of tongue nodules showed no thermal damage to the tissue, allowing an adequate histopathological analysis of the neurofibroma.

Benefícios da laserterapia nas lesões bucais da Epidermólise Bolhosa / Benefits of laser therapy in oral lesions of epidermolysis bullosa

A Epidermólise Bolhosa (EB) é um grupo de dermatoses bolhosas hereditárias que acometem a pele e mucosas. No presente trabalho, uma paciente do sexo feminino, seis anos, que foi diagnosticada ao nascimento como sendo portadora da EB distrófica, apresentou, ao exame clínico, ulcerações e bolhas na língua, mucosa jugal, palato, assoalho bucal, vestíbulos e gengivas, microstomia, anquiloglossia, ausência de vestíbulo bucal e lingual e apinhamento dentário. Toda essa condição oral acarretava à paciente dificuldade e sintomatologia dolorosa na alimentação e na higienização, além de dificultar o trabalho do profissional de Odontologia. O tratamento das lesões intraorais com irradiações por laser em baixa intensidade (comprimento de onda = 660 nm) foi proposto visto suas ações biomoduladora, anti-inflamatória, antiálgica, antiedematosa e cicatrizante. Foram realizadas, semanalmente, aplicações pontuais com dose de 90 J/cm² e potência de 40 mW (área de spot de 0,04 cm2). Após laserterapia, observou-se aumento da abertura de boca, melhora da higienização, da alimentação, com introdução de alimentos mais duros, aumento do conforto nestas tarefas, diminuição do número de bolhas intraorais, quando não havia problemas sistêmicos comprometedores, e realização do tratamento odontológico de forma menos traumática e desconfortável para a paciente (AU).

The Epidermolysis Bullosa (EB) is a group of inherited bullous skin diseases that affect the skin and mucous membranes. In the present work, a 6-year-old female patient who was diagnosed at birth as bearer of dystrophic EB, presented, at clinical examination, ulcers and blisters on the tongue, buccal mucosa, palate, mouth floor, vestibule and gums, microstomia, ankyloglossia, absence of buccal and lingual vestibule, and dental crowding. This oral condition brought to the patient pain symptomatology and difficulty to feed and to do oral hygiene, as well as hindered dental professional work. The treatment of intra-oral lesions with laser irradiation at low intensity (wavelength = 660 nm) was proposed due to its biomodulator, antiinflammatory, analgesic, anti-edematous, and healing effects. Punctual weekly applications of 90 J/cm² and power of 40 MW were made. After laser therapy, there was increase of mouth opening, improved oral hygiene, and better feeding, with the introduction of hard food, increased comfort in these tasks, reduction of intra-oral blisters number, when there was no systemic problems compromising, and dental treatment was performed in a less traumatic and uncomfortable way for the patient (AU).

In vivo probiotic and antimicrobial photodynamic therapy as alternative therapies against cryptococcosis are ineffective.

Cryptococcosis, an invasive fungal infection distributed worldwide that affects both domestic and wild animals, has incredible rates regarding treatment failure, leading to the necessity of the development of new therapies. In this way, we aimed to evaluate the probiotic (Saccharomyces boulardii, Lactobacillus paracasei ST-11, and Lactobacillus rhamnosus GG) and antimicrobial photodynamic alternative therapies against Cryptococcus gattii in a murine model. Although previous studies suggest that these therapies can be promising against cryptococcosis, our experimental conditions for both probiotic and antimicrobial photodynamic therapies (aPDT) were not able to improve the survival of mice with cryptococcosis, even with the treatment combined with fluconazole. Our results may help other researchers to find the best protocol to test alternative therapies against Cryptococcus gattii.

Evaluation of polymeric PLGA nanoparticles conjugated to curcumin for use in aPDT

ABSTRACT Antimicrobial photodynamic therapy (aPDT) involves the association of a photosensitizing agent with a light source with the goal of causing apoptosis or microbial lysing. The use of compounds with natural active principles is gaining prominence throughout the world. Several studies from groups that are linked to the development of innovations in the pharmaceutical market have used natural dyes, such as curcumin, the efficacy of which has been demonstrated in aPDT trials. Difficulties related to physicochemical stability, solubility and cell penetration are some of the challenges associated with this field. The present work aimed to prepare, investigate the characteristics and improve the photodynamic activity of PLGA-based nanoparticles loaded with curcumin for use in aPDT therapy. Using the simple technique of emulsion during the evaporation of a solvent, the particles were built, characterized and tested against microorganisms with importance for medicine and dentistry. The results revealed that the particles were able to protect the curcumin against degradation and eliminate some microorganism species at nanomolar concentrations.

Monitoring the effectiveness of photodynamic therapy with periodic renewal of the photosensitizer on intracanal Enterococcus faecalis biofilms.

BACKGROUND AND OBJECTIVE: Photodynamic therapy (PDT) can eliminate microorganisms in a root canal. However, the parameters for disinfection remain undefined. This study assessed the effectiveness of a PDT protocol against intracanal Enterococcus faecalis biofilms. MATERIALS AND METHODS: Root canals were contaminated with E. faecalis for 21 days. The instrumentation was associated to irrigation with 0.85% saline or an alternate irrigation (AI) with 5.25% NaOCl and 17% EDTA. Complementary treatments included saline/PDT and AI/PDT. Four PDT cycles were performed using a diode laser (660nm, 40mW) delivered through a tapered optical fiber. In each cycle, the root canal was filled with 1.56µM/mL methylene blue and irradiated for 150s. Microbiological samples were collected before (S1) and after (S2) instrumentation; after PDT (S3); and daily over the course of 14 days (S4-S17). Colony-forming units (CFUs) were counted, positive cultures verified, and data subjected to parametric and proportion's tests. RESULTS: The highest bacterial load reduction was observed in S2. In regard to S3, Saline/PDT reduced 1.3 log(10) CFU counts (p=0.000 for S2) and no CFUs were recovered after AI/PDT treatment. All canals were CFU-free on the 14th day for saline/PDT, AI and AI/PDT. Positive cultures were observed in 60% of saline-irrigated canals on the 14th day, whereas the saline/PDT, AI and AI/PDT treatments resulted in germ-free canals after 10, 5 and 2 days, respectively. CONCLUSION: Our findings suggest immediate and delayed antibacterial effects using the PDT protocol tested.

Avaliação do efeito térmico do laser de diodo de alta potência e do bisturi elétrico após incisões em mandíbula de porco / Evaluation of thermic effect of high power diode laser and electric bistoury after incisions in pig jaws

Atualmente, equipamentos que facilitam as cirurgias e diminuem as complicações pós- -operatórias vêm sendo utilizados por profissionais da área de saúde, dentre eles estão os lasers e os bisturis elétricos. O laser de diodo de alta intensidade é utilizado para cirurgias em tecido mole, como incisões na gengiva e na mucosa oral, com pouco ou nenhum sangramento, devido ao selamento dos vasos sanguíneos e efeito analgésico pelo selamento das terminações nervosas. O bisturi elétrico, quando utilizado como técnica de cauterização, produz calor por meio de uma corrente elétrica, que é transmitido diretamente para os tecidos alvos, com o intuito de conseguir efeitos terapêuticos favoráveis. Este estudo objetivou avaliar a variação de temperatura de incisões feitas em mandíbulas de porco. Foram realizadas incisões lineares utilizando-se um laser de diodo de alta intensidade e um bisturi elétrico. A temperatura durante as incisões cirúrgicas, utilizando ambos os equipamentos, foi avaliada por meio de análises termográficas. O bisturi elétrico produziu maior aumento da temperatura tecidual se comparado ao laser de alta potência. Este estudo concluiu que a utilização do laser de diodo foi mais segura pois a temperatura máxima atingida foi inferior quando comparada ao bisturi elétrico (AU).

Currently, health care professionals have been using equipment to facilitate the surgery and reduce postoperative complications, being among these equipment lasers and electrocautery. The high power laser diode is used for soft tissue surgery, such as incisions in the gingiva and the oral mucosa, with little or no bleeding, because of the sealing of blood vessels and the analgesic effect due to the sealing of terminations. The electrocautery used as thermal ablation technique produces heat by an electric current which is passed directly to target tissues, in order to achieve favorable therapeutic effects. The aim of this study was evaluate the temperature variation using such equipment during incisions in pig jaws. Linear incisions were made using a high intensity diode laser and electrocautery. The temperature during surgical incisions, using both equipment, was evaluated by thermographic analyses. The electrocautery produced a greater increase in tissue temperature compared to the high power laser. This study concluded that the use of diode laser is safer because the maximum temperature reached was lower when compared to the electrocautery (AU).

Melanin protects Paracoccidioides brasiliensis from the effects of antimicrobial photodynamic inhibition and antifungal drugs.

Paracoccidioidomycosis (PCM) is a public health concern in Latin America and South America that when not correctly treated can lead to patient death. In this study, the influence of melanin produced by Paracoccidioides spp. on the effects of treatment with antimicrobial photodynamic inhibition (aPI) and antifungal drugs was evaluated. aPI was performed using toluidine blue (TBO) as a photosensitizer and a 630-nm light-emitting diode (LED) light. The antifungals tested were itraconazole and amphotericin B. We evaluated the effects of each approach, aPI or antifungals, against nonmelanized and melanized yeast cells by performing susceptibility tests and by quantifying oxidative and nitrosative bursts during the experiments. aPI reduced nonmelanized cells by 3.0 log units and melanized cells by 1.3 log units. The results showed that melanization protects the fungal cell, probably by acting as a scavenger of nitric oxide and reactive oxygen species, but not of peroxynitrite. Melanin also increased the MICs of itraconazole and amphotericin B, and the drugs were fungicidal for nonmelanized and fungistatic for melanized yeast cells. Our study shows that melanin production by Paracoccidioides yeast cells serves a protective function during aPI and treatment with itraconazole and amphotericin B. The results suggest that melanin binds to the drugs, changing their antifungal activities, and also acts as a scavenger of reactive oxygen species and nitric oxide, but not of peroxynitrite, indicating that peroxynitrite is the main radical that is responsible for fungal death after aPI.

Terapia fotodinâmica antimicrobiana no tratamento de candidíase em paciente com prótese total mucossuportada superior - relato de caso / Candidiasis treatment with antimicrobial photodynamic therapy in patient with upper complete denture - case report

As próteses totais mucossuportada têm por objetivo reabilitar o sistema estomatognótico de pacientes desdentados totais, restabelecendo a saúde das estruturas de suporte bucais. Apesar da constante busca pela perfeição na confecção de próteses totais, lesões como a Candidíase podem estar associadas ao seu uso. O objetivo deste trabalho foi apresentar um caso clínico de estomatite protética tratada por meio da Terapia Fotodinâmica Antimicrobiana (aPDT), associada ao tratamento protético. O presente estudo mostrou que a luz emitida pelo laser associada ao CHIMIOLUX© foi eficiente em reduzir o número de células de C. albicans e regredir as manifestações clínicas da candidíase atrófica crônica. Assim, aPDT pode ser considerada uma alternativa viável ao tratamento coadjuvante para as lesões fúngicas intraorais e alternativa terapêutica para desinfecção de PTM. Apesar da eficiência da aPDT, a necessidade de orientar o paciente quanto … mudança de hábitos de higiene bucal e utilização de próteses adaptadas são de grande importância na manutenção da saúde dos tecidos orais

Complete mucous membrane-supported dentures aim to rehabilitate the stomatognathic system of edentulous patients, restoring oral health. Even with a constant search to improve complete dentures’ manufacturing process some adverse effects such as candidiasis may still occur. The aim of this study was to present a clinical case of denture stomatitis treated by Antimicrobial Photodynamic Therapy (aPDT), associated with prosthetic treatment. This study showed that the laser light associated with CHIMIOLUX© is effective in reducing the number of cells of C. albicans and to reverse clinical manifestations of chronic atrophic candidiasis. Thus, the aPDT can be considered a viable alternative to adjuvant treatment for denture stomatitis caused by C. albicans and to reverse clinical manifestations of chronic atrophic candidiasis. The aPDT can also be used for disinfection of complete dentures. Despite the efficiency of the aPDT, counseling the patients about oral hygiene and the use of adapted prostheses has great importance in preserving the health of oral tissues

Contaminação bacteriana e fúngica dos telefones celulares da equipe de saúde num hospital em Minas Gerais / Bacterial and fungal contamination of mobile phones belonging to the health team of a hospital in Minas Gerais State / Contaminación bacteriana y fúngica de los teléfonos celulares del equipo de salud en un hospital en Minas Gerais

Análise microbiológica que objetivou determinar as principais espécies bacterianas e fúngicas presentes nos aparelhos celulares e nas cavidades bucal e nasal da equipe de saúde, de um hospital de uma cidade do interior de Minas Gerais. Foram aplicados questionários e coletadas amostras de secreção da cavidade oral, nasal e do aparelho celular em uso. Os microrganismos foram identificados, e a susceptibilidade a antimicrobianos foi avaliada. Em 60 amostras coletadas, 40% dos profissionais foram portadores de Staphylococcus aureus, e 6,7% apresentaram esta bactéria no celular. Todos os isolados foram classificados como resistentes à penicilina e 3,57% à oxacilina. Não foram isolados fungos. Os aparelhos celulares utilizados em estabelecimentos de saúde são passíveis de veicular agentes infecciosos e constituir fômites potenciais na transmissão de infecções, se não descontaminados após o uso.

This is a bacteriological analysis that aimed to determine the most common bacterial and fungal species on the mobile phones, and the oral and nasal cavities of the healthcare team of a hospital in Minas Gerais state. Questionnaires were applied and samples of secretions from the oral and nasal cavity, and used mobile phones were collected. The microorganisms were identified and the susceptibility to antimicrobials was analyzed. In 60 samples, Staphylococcus aureus was found in 40% of the professionals and 6.7% of this bacterium was present on the mobile phones. All isolates were classified as resistant to penicillin and 3.57% to oxacillin. Fungi were not isolated. The mobile phones used in health centers can become vehicles for infectious agents and be potential vectors for transmission of infections, in case they are not decontaminated after being used.

Análisis microbiológico que tuvo el objetivo de determinar las principales especies bacterianas y fúngicas presentes en los teléfonos móviles y en las cavidades bucal y nasal del equipo de salud de un hospital de una ciudad del interior de Minas Gerais. Se aplicaron cuestionarios y se recogieron muestras de secreción de la cavidad oral, nasal y del teléfono móvil en uso. Los microorganismos fueron identificados y la susceptibilidad a antimicrobianos fue evaluada. En 60 muestras recogidas, el 40% de los profesionales fueron portadores de Staphylococcus aureus y el 6,7% presentaron esta bacteria en el móvil. Todos los aislados fueron clasificados como resistentes a la penicilina y el 3,57% a la oxacilina. No fueron aislados hongos. Los teléfonos móviles utilizados en los centros de salud son pasibles de conducir agentes infecciosos y constituir fómites potenciales en la transmisión de infecciones, si no descontaminados después del uso.

Photodynamic inhibition of Trichophyton rubrum: in vitro activity and the role of oxidative and nitrosative bursts in fungal death.

OBJECTIVES: Antimicrobial photodynamic inhibition (aPI) is based on the use of a light source and a photosensitizer to kill pathogens. Little is known about aPI of dermatophytic fungi and its mechanism of action. We aimed to evaluate aPI of Trichophyton rubrum. METHODS: We performed tests using toluidine blue (TBO) as a photosensitizer and a 630 nm light-emitting diode (LED) as a source of light to target 12 T. rubrum isolates. Susceptibility testing with cyclopiroxolamine, time-kill curves and quantification of reactive oxygen species (ROS), peroxynitrite (ONOO·) and nitric oxide (NO·) were performed. RESULTS: The optimal conditions for in vitro aPI were 10 mg/L for TBO and 48 J/cm(2) for LED; these conditions were fungicidal or inhibited >98% of fungal growth depending on the strain tested. LED or TBO treatment alone did not inhibit growth. The MICs of cyclopiroxolamine were 2.0 mg/L for 90% of the strains. Analysis of time-kill curves revealed that pathogen death occurred 24 h post-treatment. Quantification of ROS, ONOO· and NO· revealed improvement after aPI. CONCLUSIONS: Photodynamic inhibition was more efficient in promoting cell death than the antifungal cyclopiroxolamine against T. rubrum. ROS, ONOO· and NO· were important in the fungicidal activity of aPI. A suggested mechanism for this activity is that TBO is excited by LED light (630 nm), reacts with biomolecules and increases the availability of transition electrons and substrates for nitric oxide synthase, thereby increasing the oxidative and nitrosative bursts in the fungal cell.

Phototoxic action of light emitting diode in the in vitro viability of Trichophyton rubrum.

BACKGROUND: Trichophyton rubrum is the most common agent of superficial mycosis of the skin and nails causing long lasting infections and high recurrence rates. Current treatment drawbacks involve topical medications not being able to reach the nail bed at therapeutic concentrations, systemic antifungal drugs failing to eradicate the fungus before the nails are renewed, severe side effects and selection of resistant fungal isolates. Photodynamic therapy (PDT) has been a promising alternative to conventional treatments. OBJECTIVES: This study evaluated the in vitro effectiveness of toluidine blue O (TBO) irradiated by Light emitting diode (LED) in the reduction of T. rubrum viability. METHODS: The fungal inoculums' was prepared and exposed to different TBO concentrations and energy densities of Light emitting diode for evaluate the T. rubrum sensibility to PDT and production effect fungicidal after photodynamic treatment. In addition, the profiles of the area and volume of the irradiated fungal suspensions were also investigated. RESULTS: A small reduction, in vitro, of fungal cells was observed after exposition to 100 µM toluidine blue O irradiated by 18 J/cm² Light emitting diode. Fungicidal effect occurred after 25 µM toluidine blue O irradiation by Light emitting diode with energy density of 72 J/cm². The analysis showed that the area and volume irradiated by the Light emitting diode were 52.2 mm² and 413.70 mm³, respectively. CONCLUSION: The results allowed to conclude that Photodynamic therapy using Light emitting diode under these experimental conditions is a possible alternative approach to inhibit in vitro T. rubrum and may be a promising new treatment for dermatophytosis caused by this fungus.

Phototoxic action of light emitting diode in the in vitro viability of Trichophyton rubrum / Ação fototóxica do diodo emissor de luz na viabilidade de Trichophyton rubrum in vitro

BACKGROUND: Trichophyton rubrum is the most common agent of superficial mycosis of the skin and nails causing long lasting infections and high recurrence rates. Current treatment drawbacks involve topical medications not being able to reach the nail bed at therapeutic concentrations, systemic antifungal drugs failing to eradicate the fungus before the nails are renewed, severe side effects and selection of resistant fungal isolates. Photodynamic therapy (PDT) has been a promising alternative to conventional treatments. OBJECTIVES: This study evaluated the in vitro effectiveness of toluidine blue O (TBO) irradiated by Light emitting diode (LED) in the reduction of T. rubrum viability. METHODS: The fungal inoculums' was prepared and exposed to different TBO concentrations and energy densities of Light emitting diode for evaluate the T. rubrum sensibility to PDT and production effect fungicidal after photodynamic treatment. In addition, the profiles of the area and volume of the irradiated fungal suspensions were also investigated. RESULTS: A small reduction, in vitro, of fungal cells was observed after exposition to 100 µM toluidine blue O irradiated by 18 J/cm² Light emitting diode. Fungicidal effect occurred after 25 µM toluidine blue O irradiation by Light emitting diode with energy density of 72 J/cm². The analysis showed that the area and volume irradiated by the Light emitting diode were 52.2 mm² and 413.70 mm³, respectively. CONCLUSION: The results allowed to conclude that Photodynamic therapy using Light emitting diode under these experimental conditions is a possible alternative approach to inhibit in vitro T. rubrum and may be a promising new treatment for dermatophytosis caused by this fungus.

FUNDAMENTOS: Trichophyton rubrum é o agente mais comum das micoses superficiais de pele e unhas causando infecções de longa duração e altas taxas de recidiva. As desvantagens do tratamento atual envolvem medicações tópicas as quais não são capazes de alcançar o leito ungueal em concentrações terapêuticas, antifúngicos sistêmicos que não erradicam o fungo antes das unhas serem renovadas, efeitos colaterais graves e seleção de isolados fúngicos resistentes. A terapia fotodinâmica tem sido uma alternativa promissora aos tratamentos convencionais. OBJETIVOS: Este estudo avaliou a eficácia, in vitro, de azul de orto-toluidina irradiado por diodo emissor de luz na redução da viabilidade de T. rubrum. MÉTODOS: O inóculo fúngico foi preparado e exposto a diferentes concentrações de azul de orto-toluidina e densidades de energia do diodo emissor de luz, para avaliar a sensibilidade de T. rubrum e o efeito fungicida, após terapia fotodinâmica. Além disso, os perfis da área e volume das suspensões fúngicas irradiados também foram investigados. RESULTADOS: Uma pequena redução, in vitro, de células fúngicas foi observada após a exposição a 100 mM azul de orto-toluidina irradiados por diodo emissor de luz a 18 J/cm². Efeito fungicida ocorreu após irradiação 25 µM orto-toluidina por diodo emissor de luz com densidade de energia de 72 J/cm². A análise mostrou que a área e o volume irradiados pelo diodo emissor de luz foram 52,2 mm² e 413,70 mm³, respectivamente. CONCLUSÕES: Os resultados permitiram concluir que a terapia fotodinâmica com diodo emissor de luz, nas condições experimentais é uma abordagem alternativa para inibir, in vitro, T. rubrum e pode ser um tratamento promissor para as dermatofitoses causadas por este fungo.

Cryptococcus gattii: in vitro susceptibility to photodynamic inactivation.

Cryptococus gattii is an emergent primary human pathogen that causes meningismus, papilledema, high intracranial pressure and focal involvement of the central nervous system in immunocompetent hosts. Prolonged antifungal therapy is the conventional treatment, but it is highly toxic, selects for resistant strains, contributes to therapy failure and has a poor prognosis. Photodynamic inactivation (PDI) offers a promising possibility for the alternative treatment of cryptococcosis. The aim of this study was to test the effectiveness of toluidine blue O (TBO) and light-emitting diode (LED) against C. gattii strains with distinct susceptibility profile to antifungal drugs (amphotericin B: 0.015-1.0 µg mL(-1); itraconazole: 0.015-2 µg mL(-1); fluconazole: 4-64 µg mL(-1)). Using 25 µM (6.76 µg mL(-1)) TBO and LED energy density of 54 J cm(-2) these fungal isolates presented variable susceptibility to PDI. The production of reactive oxygen species (ROS)/peroxynitrite was determined, and the catalase and peroxidase activities were measured. After PDI, high amounts of ROS/peroxynitrite are produced and higher catalase and peroxidase activities could be correlated with a lower susceptibility of C. gattii isolates to PDI. These results indicate that PDI could be an alternative to C. gattii growth inhibition, even of isolates less susceptible to classical antifungal drugs, also pointing to mechanisms related to their variable susceptibility behavior.

Coordination to gallium(III) strongly enhances the potency of 2-pyridineformamide thiosemicarbazones against Cryptococcus opportunistic fungi.

A family of 2-pyridineformamide-derived thiosemicarbazones and their gallium(III) complexes were tested against several isolates of pathogenic Cryptococcus strains. On complexation the antifungal activity significantly increases, suggesting coordination to gallium(III) to be an interesting strategy of antifungal dose reduction.

In vitro photodynamic inactivation of Candida spp. growth and adhesion to buccal epithelial cells.

In this study, photodynamic inactivation (PDI) was used to inhibit in vitro growth and adhesion of different Candida isolates to buccal epithelial cells (BEC). Experimental conditions were optimized and 25muM toluidine blue O (TBO) and 15min of irradiation time by light emitting diode (LED) (energy density of 180J/cm(2)) were selected due to higher reductions in cellular viability obtained after treatment. Reduction media of Log(10) 3.41 in viable cellular growth and media of 55% in the inhibition of adhesion to buccal epithelial cells were obtained. Two fluconazole resistant isolates were susceptible to PDI (Log(10) 3.54 in IB05 and Log(10) 1.95 in CG09) and a second session of this treatment for CG09 isolate inhibited cellular viability in 100%, without producing heat. The results permit to conclude that photodynamic inactivation under these experimental conditions would be a possible alternative approach to inhibit Candida spp. cellular growth and adhesion to buccal epithelial cells.

Cerebral infection caused by Cryptococcus gattii: a case report and antifungal susceptibility testing.

We report a clinical case of cerebral infection caused by Cryptococcus gattii in a 10 year-old boy. Clinical and laboratory exams did not demonstrate any apparent immunosuppressed state (HIV antibody and the tuberculin skin tests, both negative, were performed; blood cells count and immunoglobulin levels were within normality). Treatment was begun with amphotericin B-deoxycholate but renal toxicity signs led to its substitution by fluconazole. The infection proceeded even after treatment with fluconazole. In vitro determination of minimum inhibitory concentration values were high for itraconazole (= or > 2 microg/ml), fluconazole and 5-flucytosine (= or > 64 microg/ml) and low for amphotericin B (1.0 microg/ml). Renal toxicity signs, induced by amphotericin B, progression of infection after fluconazole, and likely in vivo resistance to this triazole made this case difficult to treat. In vitro drug interaction tests confirmed probable synergism between amphotericin B and 5-flucytosine (frational inhibitory concentration - FIC = 0.375). In contrast, a probable additive effect was observed for amphotericin B and fluconazole (FIC = 0.75). Initial treatment of persistent high intracranial pressure was insufficient and neurological surgery was necessary. Antifungal susceptibility tests and Cryptococcus species identification were important in selecting appropriate antifungal therapy.

In vitro susceptibility of isolates of Sporothrix schenckii to amphotericin B, itraconazole, and terbinafine: comparison of yeast and mycelial forms.

Forty-three clinical isolates of Sporothrix schenckii derived from humans and animals were evaluated in vitro for their susceptibility to amphotericin B, itraconazole, and terbinafine. MICs were determined by the method of micro dilution in liquid media, using protocols M27-A2 for the yeast form and M38-A for the mycelial form, both standardized by the Clinical Laboratory Standards Institute. In general, higher MICs were found for the mycelial form (intervals of up to two dilutions). In the case of amphotericin B, a significant difference in activity was observed, with higher values (p<0.05) found for the mycelial form. MICs for itraconazole and terbinafine were similar for both yeast and mycelial forms but slightly higher for mycelia. Although data presented here indicate different levels of susceptibility when both growth forms were compared, indicating an intrinsic difference between them, it is still difficult to draw a consensus as to which form correlates better with clinical findings. More studies are necessary to determine the criteria for in vitro tests that will lead to efficient therapeutic choices.