RESUMO
In recent years there have been an increasing number of in vitro and in vivo studies that show positive results regarding antimicrobial photodynamic therapy (aPDT) used in dentistry. These include applications in periodontics, endodontics, and mucosal infections caused by bacteria present as biofilms. Antimicrobial photodynamic therapy is a therapy based on the combination of a non-toxic photosensitizer (PS) and appropriate wavelength visible light, which in the presence of oxygen is activated to produce reactive oxygen species (ROS). ROS induce a series of photochemical and biological events that cause irreversible damage leading to the death of microorganisms. Many light-absorbing dyes have been mentioned as potential PS for aPDT and different wavelengths have been tested. However, there is no consensus on a standard protocol yet. Thus, the goal of this review was to summarize the results of research on aPDT in dentistry using the PubMed database focusing on recent studies of the effectiveness aPDT in decreasing microorganisms and microbial biofilms, and also to describe aPDT effects, mechanisms of action and applications.
RESUMO
A produção de slime é um importante fator de virulência dos estafilococos coagulase-negativa, permitindo-lhes aderir sobre as superfícies lisas de biomateriais, e por isso, é associada aos processos de infecção de implantes. No presente estudo a produção de slime em 27 cepas de estafilococos coagulase-negativa foi investigada por cultura em ágar vermelho Congo (77,7% de positividade), método espectrofotométrico ou damicroplaca (81,4% de positividade) e microscopia eletrônica de varredura (88,9% de positividade). Foi também avaliada a resistência de estafilococos coagula-se negativa a vários antimicrobianos usando a técnica do disco difusão. A porcentagem de resistência à penicilina G, oxacilina, eritromicina, clindamicina e gentamicinaem estafilococos produtores de slime foi respectivamente de 88,9%; 70,4%; 81,5%; 66,7% e 59,2%; todos os estafilococos coagulase-negativa foram vancomicina sensíveis. As cepas isoladas de cateter venoso central foram identificadas por método convencional e sistema API Staph. Os 27 estafilococos coagulase-negativa foram identificados como: S. saprophyticus (3,7%), S. xylosus(7,4%), S. haemolyticus (14,8%), S. epidermidis (37,0%), S. warneri (14,8%), S. lugdunensis (7,4%), S. hominis (7,4%), S. schleiferi (3,7%) e S. chromogenes (3,7%). Pode-se concluir que entre a maioria das espécies Staphylococcus coagulase-negativa houve associação entre a produção de slime, origem nosocomial das cepase reduzida sensibilidade aos antimicrobianos, sugerindo potencial patogênico no ambiente hospitalar.
Slime production is an important virulence factor of coagulase-negative Staphylococcus spp., allowing them to attach to smooth surfaces of biomaterials, and it has been associated with infections of implanted medical devices. In the present study the production of slime capsules in 27 strains of coagulase-negative Staphylococcus was investigated by culture in Congo Red agar (77.7% positivity), spectrophotometric or microplate method (81.4% positivity) and scanning electron microscopy (88.9% positivity). The resistance of coagulase-negative strains of Staphylococcus to various antimicrobial agents was also determined by agar disk diffusion. The proportion of strains resistant to penicillin G, oxacillin, erythromycin, clindamycin and gentamicin among the slime-producing staphylococci was 88.9%, 70.4%, 81.5%, 66.7% and 59.2%, respectively; all of the coagulase-negative staphylococci were susceptible to vancomycin. The strains isolated from central venous catheters were identified by a conventional method and the API Staph system. The 27 coagulase-negative taphylococcus strains were identified as: S. saprophyticus (3.7%), S. xylosus (7.4%), S. haemolyticus (14.8%), S. epidermidis (37.0%), S. warneri (14.8%), S. lugdunensis (7.4%), S. hominis (7.4%), S. schleiferi (3.7%) and S. chromogenes (3.7%). It can be concluded that in the most of the coagulase-negative Staphylococcus species there was an association between slime production, the nosocomial origin of the strains and reduced sensitivity to the antibiotics, suggesting a pathogenic potential in the hospital environment.
Assuntos
Coagulase/isolamento & purificação , Staphylococcus epidermidis/patogenicidade , Staphylococcus haemolyticus/patogenicidade , Fatores de Virulência , Infecção Hospitalar , Testes de Sensibilidade MicrobianaRESUMO
Rice and bean plants were grown in nutrient solution in the presence of three levels of N, P and K. The method of the bioevaluation of the nutricional status, in which excised roots are allowed to take up tagged elements, in this case 15N and 32P, was compared with foliar analysis. Two main conclusions were drawn: 1) the bioevaluation proved to be an useful and rapid procedure for the diagnosis of the nutricional status of both species, since there was a significant negative correlation between absorption of N and P and dry matter yield; 2) the uptake of the tagged ions with either element by the roots of plants grown under deficient levels of N and P in the nutrient solution was inversely proportional to the leaf concentration of both nutrients.
Arroz e feijão foram cultivados em soluções nutritivas em presença de três níveis de N, P e K. O método da bioavaliação do estado nutricional em que raízes destacadas absorvem elementos marcados, no caso presente 15N e 32P, foi comparado com o de diagnose foliar. Foram tiradas duas conclusões principais: 1) os bioensaios mostraram ser um procedimento rápido e útil para o diagnóstico do estado nutricional das duas espécies, visto haver correlação significativa negativa entre absorção e produção de matéria seca; 2) a absorção de dois isótopos pelas raízes da planta previamente submetida a níveis diferentes de N e de P na solução foi inversamente proporcional aos teores foliares desses elementos.
RESUMO
Rice and bean plants were grown in nutrient solution in the presence of three levels of N, P and K. The method of the bioevaluation of the nutricional status, in which excised roots are allowed to take up tagged elements, in this case 15N and 32P, was compared with foliar analysis. Two main conclusions were drawn: 1) the bioevaluation proved to be an useful and rapid procedure for the diagnosis of the nutricional status of both species, since there was a significant negative correlation between absorption of N and P and dry matter yield; 2) the uptake of the tagged ions with either element by the roots of plants grown under deficient levels of N and P in the nutrient solution was inversely proportional to the leaf concentration of both nutrients.
Arroz e feijão foram cultivados em soluções nutritivas em presença de três níveis de N, P e K. O método da bioavaliação do estado nutricional em que raízes destacadas absorvem elementos marcados, no caso presente 15N e 32P, foi comparado com o de diagnose foliar. Foram tiradas duas conclusões principais: 1) os bioensaios mostraram ser um procedimento rápido e útil para o diagnóstico do estado nutricional das duas espécies, visto haver correlação significativa negativa entre absorção e produção de matéria seca; 2) a absorção de dois isótopos pelas raízes da planta previamente submetida a níveis diferentes de N e de P na solução foi inversamente proporcional aos teores foliares desses elementos.