Diss. (sammanfattning) Linköping : Linköpings universitet, 2005. / Härtill 4 uppsatser.

Doctor of Philosophy / Department of Biology / Lynn E. Hancock / Enterococci are gram-positive bacteria typically found as commensals in the gastro-intestinal tracts of most mammals. Enterococci, most notably Enterococcus faecalis and Enterococcus faecium, have become problematic causative agents of several nosocomially acquired infections including urinary tract infections, bacteremia, surgical sight infections, and endocarditis. These bacteria must first overcome the innate immune response in order to establish infection. Many bacteria produce capsular polysaccharides that contribute to pathogenesis by helping the microbe evade the host innate immune response. The capsular polysaccharide produced by E. faecalis has been shown to play a role in pathogenesis; however the mechanisms of innate immune avoidance were unknown. Moreover, the number of capsule serotypes produced by E. faecalis and the genetic differences that contribute to capsule serospecificity were in doubt. In the current study it is made clear that only two capsule serotypes are produced by E. faecalis and that both capsule serotypes contribute to evasion of the host innate immune system. This work shows two mechanisms by which the capsule of E. faecalis contributes to immune evasion. First, the presence of capsule inhibited complement mediated phagocytosis through limiting the detection of opsonic complement protein C3 on the surface of the bacteria. Secondly, the presence of capsule altered cytokine signaling of macrophages by shielding bacterial components from detection. Many pathogenic strains of E. faecalis also produce an extracellular protease known as gelatinase (GelE). This work also shows a novel mechanism involving GelE in innate immune evasion through the degradation of the anaphylatoxin C5a. Degradation of C5a by GelE resulted in decreased neutrophil recruitment in vitro. A rabbit model of endocarditis was employed to assess the effect of GelE production on disease development and progression. Rabbits infected with GelE producing strains had increased bacterial burdens in the heart compared to rabbits infected with strains that were GelE negative. Reduced phagocyte infiltration at primary and secondary infection sites was also observed in rabbits infected with GelE producing strains compared to GelE negative strains. The work presented here demonstrates that both the capsular polysaccharide and GelE play roles in E. faecalis evasion of innate immune responses. Moreover, these pathogenic determinants would be suitable targets for developing alternative therapeutics used to treat E. faecalis infections.

En los últimos años los casos de infecciones causadas por enterococos resistente a vancomicina (ERV) han ido cobrando importancia debido a su capacidad innata para almacenar información e inclusive transferirla a otras cepas. Los ERV han sido aislados de Unidades de Cuidados Intensivos (UCI), de infecciones de tracto urinario, bacteriemias, endocarditis, etc. Las dos especies clínicamente importantes son Enterococcus faecium y Enterococcus faecalis, las cuales portan genes de resistencia a vancomicina. El objetivo de esta investigación fue analizar genéticamente las cepas ERV del Hospital Nacional Guillermo Almenara Irigoyen (HNGAI). Para ello se recolectaron cepas ERV y se realizó la evaluación molecular en el Laboratorio de Microbiología y Biotecnología Molecular de la Universidad Nacional Mayor de San Marcos – Lima. Se seleccionaron un total de 28 cepas, 82% (n = 23) correspondieron a la especie E. faecium y 18% (n = 5) a E. faecalis. Se determinó el nivel de resistencia a vancomicina con la Concentración Mínima Inhibitoria (CMI) mediante el E-test, 23 cepas de Enterococcus faecium obtuvieron una CMI ≥ 256µg/mL; 5 cepas de Enterococcus faecalis mostraron subpoblaciones heterorresistentes a vancomicina dentro del halo de inhibición. Para determinar la ubicación de la resistencia se utilizó la prueba de curación de plásmidos resultando que el 96% (n = 22) de las cepas de E. faecium mantuvo la resistencia después del curado y el 100% de Enterococcus faecalis mostraron sensibilidad y transferibilidad, siendo la frecuencia de transferencia más alta de 5 x10-3 para la cepa EC0507. Mediante PCR múltiplex se determinó la presencia de un sólo genotipo vanA, en todas las cepas Enterococcus faecium y Enterococcus faecalis. De esta manera se concluye que existe un solo genotipo vanA en los ambientes intrahospitalarios del HNGAI y que estos pueden ser transferibles.

El propósito de este estudio fue determinar la efectividad de la asociación de Cetrimida -Clorhexidina (15% / 0.15%) frente a Clorhexidina 2%; en la erradicación de biofilms de Enterococcus faecalis in vitro. La metodología usada para este fin fue la creación de biofilms, en láminas portaobjeto de 48 horas de incubación a 37 ºC en condiciones aerobias a partir de la cepa Enterococcus faecalis ATCC 29212 en caldo BHI, las cuales fueron sometidas a los irrigantes testados durante los periodos de tiempo de 1, 3 y 5 minutos, respectivamente. Se llevaron a cabo dos grupos de experimentos independientes, más un control negativo (suero fisiológico); en tres repeticiones para cada irrigante y tiempo evaluado. Los irrigantes evaluados fueron: Cetrimida-Clorhexidina (15%/0.15%) “SAFEBLON”, Clorhexidina (2%), y Suero Fisiológico. Luego del contacto con los irrigantes, los biofilms fueron sembrados en Agar Tripticasa Soya (TSA) e incubados durante 24 horas a 37 ºC para la cuantificación final de UFC/mL y así determinar el porcentaje de inhibición bacteriana y consecuentemente la efectividad de los irrigantes. El resultado obtenido muestra que, el porcentaje de inhibición bacteriana de Biofilms de Enterococcus faecalis con Cetrimida-Clorhexidina (15%/0.15%) fue 99,99%; con Clorhexidina (2%), fue 100% y con Suero Fisiológico(control negativo) fluctuó entre 24% y 31%; durante los tiempos evaluados de 1,3 y 5 minutos. Por lo tanto, se concluye que no existe diferencia significativa en la Erradicación de biofilms de Enterococcus faecalis; mediante la aplicación de la asociación Cetrimida-Clorhexidina (15%/1.5%) y Clorhexidina 2% a cualquiera de los tres tiempos experimentados; permitiéndose utilizar indistintamente menor concentración de Clorhexidina de 2% al 0.15% , mediante el uso coadyuvante de Cetrimida 15%. Palabras Clave: Cetrimida, Surfactante, biofilms, Enterococcus faecalis, tensión superficial. / The purpose of this study was to determine the effectiveness of the association of Cetrimide-Chlorhexidine 15%/0.15% with Chlorhexidine 2% in the eradication of biofilms of Enterococcus faecalis in vitro. The used methodology for this aim was the creation of biofilms in glass slides for 48 hours of incubation at 37 ºC, in aerobic conditions from Enterococcus faecalis ATCC 29212 strains in BHI infusion. They were subjected to the tested irrigants during the periods of 1, 3 and 5 minutes, respectively. There were two groups of independent experiments and a negative control with saline solution in three repetitions for each irrigant and time tested. The tested irrigants were Cetrimide/ Chlorhexidine 15%/015%, (SAFEBLON) , Chlorhexidine 2% and physiological saline. After the contact with the irrigants , biofilms were cultivated in TSA agar and incubated during 24 hours at 37 ºC for the quantification of the UFC/mL and determine the percentage of bacterial inhibition and consequently the percentage of the irrigants effectiveness. The results obtained show that the obtained percentage of bacterial inhibition of Enterococcus faecalis biofilms with Cetrimide - Chlorhexidine (15%/0.15%) was 99,99% ; with Chlorhexidine (2%), was at 100% and with Physiological Saline (negative control) ranged between 24% and 31%; during three tested times : 1,3 and 5 minutes. Therefore, It concluded that there is no significant difference in the eradication of Enterococcus faecalis biofilms; by the application of the association Cetrimide-Chlorhexidine (15%/ 0.15%) and Chlorhexidine 2% at any of the three tested times; allowing to use indistinctly less concentration of Chlorhexidine from 2% to 0.15% by the adjuvant use of Cetrimide 15%. Keywords: Cetrimide, surfactant, biofilms, Enterococcus faecalis, surface tension

El presente trabajo in vitro evaluará la capacidad antibacteriana del yoduro de potasio yodado al 2% como un coadyuvante para la erradicación de la bacteria Enterococcus faecalis de los conductos radiculares posterior al tratamiento quimiomecánico, bajo un modelo de evaluación y control microbiológico de las paredes del conducto radicular, reproduciendo características clínicas tales como la anatomía de los conductos radiculares y el efecto mecánico de una técnica de instrumentación rotatoria.

Les entérocoques font partie de la flore normale intestinale des animaux et des humains. Plusieurs études ont démontré que les entérocoques d’origine animale pouvaient représenter un réservoir de gènes de résistance aux antibiotiques pour la communauté humaine et animale. Les espèces Enterococcus faecalis et Enterococcus faecium sont importantes en santé publique; elles sont responsables d’environ 12% de toutes les infections nosocomiales aux États-Unis. Au Canada, les cas de colonisation et/ou d’infections à entérocoques résistants à la vancomycine ont plus que triplé de 2005 à 2009. Un total de 387 isolats E. faecalis et E. faecium aviaires, et 124 isolats E. faecalis porcins ont été identifiés et analysés pour leur susceptibilité aux antibiotiques. De hauts pourcentages de résistance envers les macrolides et les tétracyclines ont été observés tant chez les isolats aviaires que porcins. Deux profils phénotypiques prédominants ont été déterminés et analysés par PCR et séquençage pour la présence de gènes de résistance aux antibiotiques. Différentes combinaisons de gènes de résistance ont été identifiées dont erm(B) et tet(M) étant les plus prévalents. Des extractions plasmidiques et des analyses par hybridation ont permis de déterminer, pour la première fois, la colocalisation des gènes erm(B) et tet(M) sur un plasmide d’environ 9 kb chez des isolats E. faecalis porcins, et des gènes erm(B) et tet(O) sur un plasmide de faible poids moléculaire d’environ 11 kb chez des isolats E. faecalis aviaires. De plus, nous avons démontré, grâce à des essais conjugatifs, que ces plasmides pouvaient être transférés. Les résultats ont révélé que les entérocoques intestinaux aviaires et porcins, lesquels peuvent contaminer la viande à l’abattoir, pouvaient représenter un réservoir de gènes de résistance envers la quinupristine-dalfopristine, la bacitracine, la tétracycline et les macrolides. Afin d’évaluer l’utilisation d’un antisérum polyclonal SA dans l’interférence de la résistance à de fortes concentrations de bacitracine (gènes bcrRAB), lors d’un transfert conjugatif répondant aux phéromones, un isolat multirésistant E. faecalis aviaire a été sélectionné. Après induction avec des phéromones produites par la souche réceptrice E. faecalis JH2-2, l’agrégation de la souche donatrice E. faecalis 543 a été observée ainsi que des fréquences de transfert élevées en bouillon lors d’une courte période de conjugaison. Le transfert conjugatif des gènes asa1, traB et bcrRAB ainsi que leur colocalisation a été démontré chez le donneur et un transconjugant T543-1 sur un plasmide de 115 kb par électrophorèse à champs pulsé (PFGE) et hybridation. Une CMI de > 2 048 µg/ml envers la bacitracine a été obtenue tant chez le donneur que le transconjuguant tandis que la souche réceptrice JH2-2 démontrait une CMI de 32 µg/ml. Le séquençage des gènes asa1, codant pour la substance agrégative, et traB, une protéine régulant négativement la réponse aux phéromones, a révélé une association de cet élément génétique avec le plasmide pJM01. De plus, cette étude présente qu’un antisérum polyclonal SA peut interférer significativement dans le transfert horizontal d’un plasmide répondant aux phéromones codant pour de la résistance à de fortes doses de bacitracine d’une souche E. faecalis aviaire multirésistante. Des isolats cliniques E. faecium d’origine humaine et canine ont été analysés et comparés. Cette étude rapporte, pour la première fois, la caractérisation d’isolats cliniques E. faecium résistants à l’ampicilline (EFRA) d’origine canine associés à CC17 (ST17) au Canada. Ces isolats étaient résistants à la ciprofloxacine et à la lincomycine. Leur résistance envers la ciprofloxacine a été confirmée par la présence de substitutions dans la séquence en acides aminés des gènes de l’ADN gyrase (gyrA/gyrB) et de la topoisomérase IV (parC/parE). Des résistances élevées envers la gentamicine, la kanamycine et la streptomycine, et de la résistance envers les macrolides et les lincosamides a également été observées. La fréquence de résistance envers la tétracycline était élevée tandis que celle envers la vancomycine n’a pas été détectée. De plus, aucune résistance n’a été observée envers le linézolide et la quinupristine-dalfopristine. Les données ont démontré une absence complète des gènes esp (protéine de surface des entérocoques) et hyl (hyaluronidase) chez les isolats canins EFRA testés tandis qu’ils possédaient tous le gène acm (adhésine de liaison au collagène d’E. faecium). Aucune activité reliée à la formation de biofilm ou la présence d’éléments CRISPR (loci de courtes répétitions palindromiques à interespaces réguliers) n’a été identifiée chez les isolats canins EFRA. Les familles de plasmide rep6 and rep11 ont significativement été associées aux isolats d’origine canine. Les profils PFGE des isolats d’origine humaine et canine n'ont révélé aucune relation (≤ 80%). Ces résultats illustrent l'importance d'une utilisation judicieuse des antibiotiques en médecine vétérinaire afin d’éviter la dissémination zoonotique des isolats EFRA canins. Nous pensons que ces résultats contribueront à une meilleure compréhension des mécanismes de résistance aux antibiotiques et de leurs éléments mobiles ainsi qu’à de nouvelles stratégies afin de réduire le transfert horizontal de la résistance aux antibiotiques et des facteurs de virulence. / Enterococci are part of normal intestinal gut flora of animals and humans. Many studies have shown that enterococci from animal origin could represent an antimicrobial resistance genes reservoir for the human community. The two species Enterococcus faecalis and Enterococcus faecium are important in public health; they are responsible for approximately 12% of all nosocomial infections in the United States. In Canada, cases of colonization and/or infections to vancomycin resistant enterococci have more than tripled from 2005 to 2009. A total of 387 poultry E. faecalis and E. faecium isolates, and 124 porcine E. faecalis isolates were identified and analyzed for their antibiotic susceptibilities. High percentages of resistance to macrolides and tetracyclines were found in both avian and porcine isolates. Two predominant phenotypic profiles were determined and analyzed by PCR and sequencing for the presence of antimicrobial resistance genes. Various combinations of antibiotic resistance genes were detected; erm(B) and tet(M) were the most common genes. For the first time, plasmid extraction and hybridization revealed colocalization of erm(B) and tet(M) on a plasmid of ~9 kb in porcine E. faecalis isolates, and of erm(B) and tet(O) on a low-molecular-weight plasmid of ~11 kb in poultry E. faecalis isolates. Furthermore, we demonstrated, through mating experiments, these plasmids could be transferred. Results indicate that the intestinal enterococci of healthy pigs and poultry, which can contaminate meat at slaughter, could be a reservoir for quinupristin-dalfopristin, bacitracin, tetracycline, and macrolide resistance genes. To assess the use of a polyclonal antiserum AS on the contact interference of a high level bacitracin resistant (bcrRAB genes) pheromone-responsive plasmid, a multiresistant E. faecalis isolate of poultry origin was selected. After induction with pheromones produced by the recipient strain E. faecalis JH2-2, clumping of the donor E. faecalis strain 543 was demonstrated as well as high transfer frequencies in short time broth mating. Conjugative transfer of asa1, traB and bcrRAB genes and their co-localization were also demonstrated in the donor strain and a transconjugant T543-1 on a plasmid band of 115 kb by PFGE and Southern blotting. A MIC to bacitracin of > 2 048 µg/ml was obtained for both strains 543 and T543-1 whereas the recipient strain JH2-2 demonstrated a MIC of 32 µg/ml. Sequencing of the asa1 gene encoding for an AS, and traB for a pheromone shutdown protein, confirmed the association of this genetic element to the pheromone-responsive plasmid related to pJM01. More significantly, this study presents the evidence that a polyclonal antiserum AS can significantly interfere with the horizontal transfer of a pheromone-responsive plasmid encoding high-level bacitracin resistance of a poultry multidrug resistant E. faecalis strain. Clinical isolates of E. faecium of human and canine origin were analyzed and compared. This report describes for the first time the characterization of canine clinical ampicillin-resistant E. faecium (AREF) isolates related to CC17 (ST17) in Canada. These isolates were resistant to ciprofloxacin and lincomycin. Resistance to ciprofloxacin was confirmed by amino acid substitutions in DNA gyrase (gyrA/gyrB) and topoisomerase IV (parC/parE) genes. High-level gentamicin, -kanamycin and -streptomycin resistances and macrolides resistance were also observed. The frequency of tetracycline resistance was high whereas vancomycin resistance was not detected. Also, no resistance was observed to linezolid and quinupristin-dalfopristin antibiotics. Data demonstrated the complete absence of enterococcal surface protein (esp) and hyaluronidase (hyl) genes among the canine AREF isolates tested while all were acm (collagen adhesin from E. faecium) positive. However, most of them were shown to harbor efaAfm gene, encoding for a cell wall adhesin. No biofilm formation or clustered regularly interspaced short palindromic repeats (CRISPR) elements were identified in these canine AREF isolates. rep6 and rep11 families of plasmids were significantly associated with isolates from dogs. The PFGE patterns of human and dog isolates were considered unrelated (≤ 80%). These findings also support the importance of prudent use of antibiotics in veterinary medicine to avoid zoonotic spread of canine AREF isolates. We are confident that our results may help to better understand the mechanisms of antibiotic resistance and mobile element carrying them as well as new strategies to reduce the horizontal transfer of antibiotic resistance and virulence traits.

Doctor of Philosophy / Department of Biology / Lynn Hancock / Enterococci are the third leading cause of nosocomial infections including urinary tract infections (UTI), surgical site infections (SSI) and blood stream infections. Enterococci are also found in the gastrointestinal tracts of humans, and other mammals. We elucidated the influence of the transcriptional regulator RpoN on enterococcal biofilm formation, virulence potential and cell wall architecture and proposed a potential involvement for carbohydrate metabolism in these processes. Biofilms are held together by matrix (BM) components such as extracellular DNA (eDNA) released by cell death from a sub-population of cells. The rpoN mutant (ΔrpoN) was resistant to autolysis as well as fratricide-mediated cell death and eDNA was not detected in planktonic as well as biofilm cultures. Unlike the parental strain V583, the ΔrpoN mutant formed proteinase K sensitive biofilms, suggesting that protein as well as eDNA serves as an important matrix component. The rabbit model of endocarditis was used to assess the effect of rpoN deletion on enterococcal virulence. Rabbits infected with ΔrpoN had reduced bacterial burden in heart, blood, liver, kidney and vegetation in comparison to the parental strain. The growth defect of ΔrpoN in physiologically relevant glucose levels (5 mM) partially explains the reduced bacterial burdens observed in the virulence study. Microarray analysis of ΔrpoN showed that 10% of the genome is differentially regulated by RpoN. Deletion of rpoN also protects Enterococcus faecalis from lysis in the absence of known modulators of cellular lytic events such as O-acetylation and D-alanylation. Of the four identified enhancer binding proteins in E. faecalis, MptR regulates the RpoN-dependent mannose/glucose uptake system (MptABCD) and the ΔmptR mutant phenocopied the ΔrpoN mutant in the eDNA release and growth assays. Because MptC and MptD have been shown to be the cellular receptors for class IIa and IIc bacteriocins, we are presently testing the hypothesis that these receptors may serve as a global receptor for bacteriocins. In conclusion, our data demonstrates that alterations in the metabolic state of the bacterium, as observed in the ΔrpoN mutant could be responsible for the switch in biofilm matrix composition, and this switch in turn likely influences the virulence potential of the bacterium.

Master of Science / Food Science / Sajid Alavi / Validation studies on process equipment are an important step for effective pathogenic control during dry expanded pet food manufacturing. The preconditioner is used to hydrate, mix and pre-cook raw materials before extrusion of pet food. The High-Intensity-Preconditioner (HIP) was designed with two independently driven shafts, thus offering control of both shaft speed and rotational direction with potential for improving residence time and thus pathogen inactivation. Residence time distribution (RTD) of raw dog food mix was impacted by the HIP process parameters (average residence time varying between 104-178 s for dry experiment and 65-177 s with steam addition) depending on shaft speed and direction. In general, increase in shaft speed resulted in shorter residence time with the larger shaft having a greater impact than the smaller shaft. Rotational direction of shafts also had an effect on average residence time (a maximum difference of 37 s was noticed between treatments with different shaft directions and the same speed). The uniformity of residence time distribution (difference of 97-132 s between 15 and 85 percentiles of the cumulative RTD) also varied considerably with process conditions, with uniformity increasing with shaft speed.  Enterococcus faecium (ATCC® 8459™) was chosen as a surrogate for Salmonella for microbial inactivation studies on the HIP. Both HIP shaft speed (200 and 300 rpm) and process temperature (67-70°C and 89-91°C) impacted E.faecium survival. Lower shaft speed (corresponding to longer residence time) or higher temperature led to greater E.faecium inactivation. A 5 log CFU/g of E.faecium was reduced using selective agar (m-Enterococcus or mE agar) after treatment with high temperature, but approximately 3.5 log CFU/g of E.faecium reduced on non-selective agar (Brain Heart Infusion or BHI agar). Uneven heat distribution, inadequate residence time and system instability might have negatively affected the inactivation. Microbial inactivation, with E.faecium as surrogate, was also studied for the complete dry expanded pet food process using a pilot-scale single-screw extruder with a regular double shaft preconditioner. Meal was inoculated with E.faecium at 6 log CFU/g and processed. Preconditioner downspout temperature ranged from 89-94°C and extrusion die temperature was between 120-140°C. Complete inactivation was observed after extrusion.

Memoria para optar al Título Profesional de Médico Veterinario / La resistencia bacteriana a antimicrobianos y su diseminación son una de las mayores epidemias del mundo en la actualidad. Hoy en día, el uso masivo, y en algunos casos, el mal uso de los antimicrobianos, han generado una presión de selección en los microorganismos, creando nuevos y mejores mecanismos de resistencia tanto en cepas bacterianas comensales como en cepas patógenas, generando un grave problema de salud pública que no cesa de aumentar de forma alarmante en todo el mundo. El objetivo de este trabajo fue caracterizar los perfiles de resistencia genotípica frente a macrólidos y aminoglucósidos en cepas indicadoras de Enterococcus spp. y Escherichia coli fenotípicamente resistentes a estos fármacos, que fueron aisladas de la microbiota intestinal de gallinas de postura. Se determinaron los genes de resistencia a eritromicina ermB, ermA, mefA, msrA/B y msrC en 37 cepas de Enterococcus spp. resistentes fenotípicamente a eritromicina y los genes de resistencia a estreptomicina aadA1, aadA2, aadE, strA y strB en 26 cepas de E. coli resistentes fenotípicamente a estreptomicina. Se utilizó la técnica de reacción en cadena de la polimerasa (PCR). El gen de resistencia a eritromicina más frecuente en cepas de Enterococcus spp. fue ermB encontrándose en 48,6% de las cepas. Los genes ermA, mefA, msrA/B y msrC no fueron encontrados en ninguna de las cepas del estudio. En cuanto a los genes de resistencia a estreptomicina, los genes más frecuentes encontrados fueron strA y strB, encontrándose en un 57,7% de las cepas de E. coli del estudio. Estos genes se encontraron siempre juntos. Los genes aadA1, aadA2 y aadE no fueron encontrados en ninguna de las cepas del estudio. Los resultados de este estudio entregan información actualizada de la situación de resistencia bacteriana en cepas indicadoras aisladas de animales productores de alimentos de alto consumo en nuestro país. Finalmente se puede señalar que los datos presentados en este trabajo podrían servir de base junto a otros estudios, para promover el desarrollo de un programa de monitoreo de la resistencia bacteriana en medicina veterinaria

Orientador: Carla Raquel Fontana Mendonça / Resumo: O presente estudo tem como objetivo avaliar a fototoxicidade do azul de metileno (AM), clorina-e6 (Ce-6) e curcumina (CUR) associados a irradiações com diferentes intensidades de luz para a terapia fotodinâmica (TFD) contra cepas de Enterococcus faecalis e Cutibacterium acnes, em suspensão e em biofilme. As fontes de luz utilizadas na TFD foram LEDs no comprimento de onda azul (450 nm) e vermelho (660 nm) de acordo com cada fotossensibilizador testado. Como resultado observamos que, em E. faecalis a TFDa mediada por AM e Ce6 foi mais eficiente quando exposta a intensidade de luz de 153 mW/cm², porém com a CUR os melhores resultados foram obtidos com a intensidade de luz de 103 mW/cm². Para C. acnes em suspensão, a Ce6 e a CUR submetidas às diferentes intensidades de luz, causaram reduções bacterianas similares. Em biofilme, a Ce6 associada a intensidade de 122 mW/cm² de luz foi mais eficiente, no entanto, a CUR não proporcionou morte de biofilmes de C. acnes independente das intensidades testadas. O AM, independente da fase, apresentou os melhores resultados com a intensidade de luz de 153 mW/cm². Considerando a quantificação de espécies reativas de oxigênio, a concentração de AM foi determinante na produção de EROs. Na concentração de 100 μg/mL de AM na dose de 120 J/cm2 radicais hidroxila foram mais evidentes em relação a quantidade de oxigênio singleto formado. Na concentração de 50 μg/mL, a intensidade de 61 mW/cm² gerou similarmente as espécies testadas, quanto que a int... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor