Francine Cristina da Silva

Antimicrobial photodynamic inactivation of Staphylococcus aureus biofilms in bone specimens using methylene blue, toluidine blue ortho and malachite green: An in vitro study.

OBJECTIVE To evaluate the in vitro effectiveness of APDI with a 660 nm laser combined with methylene blue (MB), toluidine blue ortho (TBO) and malachite green (MG) dyes to inactivate Staphylococcus aureus (ATCC 25923) biofilms in compact and cancellous bone specimens. METHODS Eighty specimens of compact and 80 of cancellous bone were contaminated with a standard suspension of the microorganism and incubated for 14 days at 37°C to form biofilms. After this period, the specimens were divided into groups (n=10) according to established treatment: PS-L- (control - no treatment); PSmb+L-, PStbo+L-, PSmg+L- (only MB, TBO or MG for 5 min in the dark); PS-L+ (only laser irradiation for 180 s); and APDImb, APDItbo and APDImg (APDI with MB, TBO or MG for 180 s). The findings were statistically analyzed by ANOVA at 5% significance levels. RESULTS All experimental treatments showed significant reduction of log CFU/mL S. aureus biofilms when compared with the control group for compact and cancellous bones specimens; the APDI groups treatment was more effective. The APDI carried out for the compact specimens showed better results when compared with cancellous specimens at all times of application. For the group of compact bone, APDImg showed greater reductions in CFU/mL (4.46 log 10). In the group of cancellous bone, the greatest reductions were found in the APDImb group (3.06 log 10). CONCLUSION APDI with methylene blue, toluidine blue ortho and malachite green dyes and a 660 nm laser proved to be effective in the inactivation of S. aureus biofilms formed in compact and cancellous bone.

Effectiveness of antimicrobial photodynamic therapy using a 660 nm laser and methyline blue dye for inactivating Staphylococcus aureus biofilms in compact and cancellous bones: An in vitro study

BACKGROUND New therapeutic modalities such as antimicrobial photodynamic therapy (APDT) has been investigated in order to be a valid alternative to the treatment of infections caused by different microorganisms. This work evaluated the in vitro effectiveness of Antimicrobial Photodynamic Therapy (APDT) using 660 nm laser combined with methylene blue dye to inactivate Staphylococcus aureus (ATCC 25923) biofilms in compact and cancellous bones specimens. METHODS Eighty specimens of compact bone and 80 specimens of cancellous bone were contaminated with a standard suspension of S. aureus and incubated for 14 days at 37°C to induce the formation of biofilms. The specimens were then divided into groups (n = 10) according to the established treatment: PS-L- (control--no treatment), PS+L- (only AM for 5 min in the dark), PS-L+90 (only laser irradiation for 90 s), PS-L+180 (only laser irradiation for 180 s), PS-L+300 (only laser irradiation for 300 s), APDT90 (APDT for 90 s), APDT180 (APDT for 180 s), and APDT300 (APDT for 300 s). The findings were statistically analyzed by ANOVA 5%. RESULTS All of the experimental treatments showed a significant reduction (log 10 CFU/mL) of S. aureus biofilms in compact and cancellous bones specimens compared with the control group, and the APDT group was the most effective. Compact specimens treated with APDT showed the greatest reduction in biofilms compared with cancellous specimens, regardless of length of treatment. CONCLUSION APDT with methylene blue dye and a 660 nm laser proved to be effective in inactivating S. aureus biofilms formed in compact and cancellous bone.

Antimicrobial Photodynamic Therapy: A New Therapeutic Option to Combat Infections

Minimization or elimination of antibiotic resistance in microbial species is an urgent need of the present times. Antimicrobial photodynamic therapy is a new therapeutic option through which development of resistance in microorganisms can be avoided. Interest in the use of photodynamic therapy to combat microbial infection is not only linked to the fact that this technique prevents antibiotic resistance in microorganisms, but is also due to the broad-spectrum antimicrobial effect, selectivity, with little or no local or systemic side effects, to microorganisms, ease of application of the technique, among other beneficial features. In this review, the major aspects related to the use of antimicrobial photodynamic therapy with respect to the major photosensitizing dyes and light sources used in the therapy have been discussed. In addition, current applications, wherein the use of the technique has yielded successful results, have also been discussed along with the possibility of future applications of this new therapeutic option to combat infections.

Application of photodynamic therapy, laser therapy, and a cellulose membrane for calcaneal pressure ulcer treatment in a diabetic patient: A case report

Diabetes mellitus is a metabolic disorder in which a person has high blood glucose levels due to inadequate insulin production by the pancreas. Wounds in these individuals cannot heal properly over time due to circulatory changes that hinder and stagnate the healing process. We report the case of an 82-year-old female type 2 diabetes mellitus carrier, presenting to clinical-dermatological examination pressure ulcer (PU) in the right calcaneus region. The patient was treated with photodynamic therapy using curcumin and blue light-emitting diodes (LEDs), laser therapy, and the application of a cellulose membrane in order to promote ulcer decontamination by local action, accelerate wound healing, and maintain favorable conditions of asepsis and moisture, respectively. The ulcer healing occurred after 30days of treatment and total epithelialization was observed. From the results obtained in this case report, we conclude that the combination of photodynamic therapy, laser therapy, and coating with a cellulose membrane is a promising treatment for the healing of PU in diabetic patients.

Prevalence of Candida yeasts in oral samples from children with AIDS and children exposed and not exposed to HIV served by SUS in the state of Bahia, Brazil

OBJECTIVE: This study aimed to determine the prevalence of Candida albicans and non-albicans yeast species isolated from oral samples of children with AIDS and of children exposed and not exposed to HIVduring pregnancy and served by the public health system in a county located in the interior of the state of Bahia, Brazil. METHODS: Saliva samples from 50 children aged between 2 and 12 years treated by SUS (group I = control group, group II = group exposed to HIV without seroconversion, and group III = AIDS carriers) were collected, seeded in Sabouraud dextrose agar with chloramphenicol, and fungal cultures were grown at 35 ± 2° C for 24 hours. Three isolated colonies were randomly selected from each individual plaque for identification using the API20 AUX Biomerieux® method. RESULTS: The most frequent fungal species in samples from children not exposed to HIV, exposed to HIV, and AIDS carriers was Candida albicans (48.80%, 25.64%, and 58.13%, respectively). Species of Candida non-albicans were also isolated from all groups studied. CONCLUSIONS: Despite the higher prevalence of Candida albicans in these groups, non-albicans species represented a significant percentage of Candida isolates.

Reduced methicillin-resistant Staphylococcus aureus biofilm formation in bone cavities by photodynamic therapy

Photodynamic Therapy (PDT) is a promising alternative for the treatment of infectious bone lesions in the oral cavity. The objective of this study was to evaluate the antimicrobial effectiveness of PDT using blue LED associated with curcumin in methicillin-resistant Staphylococcus aureus biofilms (MRSA) in bovine bone cavities by fluorescence spectroscopy. Standardized suspensions of MRSA culture were inoculated into bone lesions to form biofilm. Forty bone species were distributed in three distinct groups: L-C- (control); L + C- (LED for 5 min); L-C+ (curcumin incubation for 5 min) and L + C+ (PDT). Aliquots of 100 μL were collected from the bone cavities after the treatments and were cultived in BHI for 24 h at 36 °C ± 1 and bacterial colonies counting were performed. Statistical analysis were performed using the paired t-test and analysis of variance (ANOVA) for the variables studied. RESULTS The control and PDT groups presented statistically significant differences (p < 0.001). It was possible to reduce 3.666 log10 CFU/mL of MRSA and a reduction in the fluorescence emitted after the treatments was observed. The MRSA reduction in biofilms by PDT was the most efficient treatmnent. There was a significant reduction of biofilms in the L + C- and non-PDT groups by fluorescence spectroscopy images.

Effectiveness of photodynamic therapy on Candida species isolated from oral samples of children exposed and not exposed to HIV

Objetivo: Identificar especies de leveduras isoladas de criancas nao expostas, expostas ao HIV e portadoras de AIDS, e verificar a eficacia da terapia fotodinâmica com laser de baixa potencia sobre as especies de leveduras pertencentes ao genero Candida. Metodos: Cinquenta criancas atendidas pelo Programa de Saude Publica da cidade de Vitoria da Conquista, Bahia, foram selecionadas e divididas em tres grupos: nao expostas ao HIV, expostas ao HIV durante a gravidez e portadoras da AIDS. Amostras de saliva foram coletadas em um recipiente universal descartavel esteril e foram semeadas em agar Sabouraud dextrose suplementado com 0,1 mg / mL de cloranfenicol. As placas foram incubadas a 37°C durante 48h. Tres cepas de cada paciente foram identificadas utilizando o sistema API 20 C AUX. As cepas foram submetidas a Terapia Fotodinâmica com laser de baixa potencia de 660 nm e corante azul de metileno em diferentes tempos de irradiacao (90, 180 e 282 segundos). Resultados: Os resultados mostraram que a especie isolada mais prevalente nos grupos estuddos foi Candida albicans, seguida de Candida famata (segunda mais prevalene nos grupos nao expostos ao HIV e com AIDS) e Candida parapsilosis (segunda mais prevalente no grupo exposto ao HIV). Houve diminuicao significante de CFU/ml de Candida spp. (p <0,05) em todos os grupos tratados com terapia fotodinâmica, em comparacao com os controles. A terapia fotodinâmica, nos diferentes tempos (e.g., PS+L90+, PS+L180+, PS+L282+) mostrou que o tempo de 282 seg. apresentou a maior reducao em media de logaritmo de UFC/mL. Conclusao: Candida albicans foi a especie de Candida mais prevalente isolada nos tres grupos e as especies de Candida nao-albicans, quando combinadas, contribuiram com porcentagem significativa dos isolados de Candida. A PDT foi eficaz na inativacao de Candida spp. isoladas a partir da cavidade oral de criancas nao expostas, expostas ao HIV e portadoras da AIDS, com o melhor tempo de irradiacao sendo o de 282 seg.