Comparative analysis of biofilm formation by Candida albicans and Candida krusei in different types of contact lenses / Análise comparativa da formação de biofilmes, por Candida albicans e Candida krusei, em diferentes tipos de lentes de contato

ABSTRACT Objective: To evaluate the Candida krusei and Candida albicans biofilm formation abilities on 5 different types of contact lenses and compare their metabolic activities and biomass. Methods: After biofilm formation by both the test species, their metabolic activity was assessed by the 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide reduction assay with menadione, while the biomass was determined by staining with 0.4% crystal violet dye for further statistical analysis. Results: Both the Candida species could form biofilms on different types of contact lenses, with greater metabolic activities and lower biomass formation in rigid gas permeable lenses. Conclusion: Biofilm formation with greater metabolic activity and greater biomass were expected on soft contact lenses considering their surface hydrophobicity. However, the results demonstrated a greater metabolic activity on rigid contact lenses. This result has a great significance with regards to the increasing risk of microbial keratitis, although further studies are warranted to better elucidate the formation of biofilms on different types of contact lens materials in the future.

RESUMO Objetivo: Avaliar a capacidade de formação de bio­filmes de Candida krusei e Candida albicans em cinco tipos de lentes de contato, comparando atividade metabólica e biomassa dos mesmos. Métodos: Após a formação de biofilme de ambas as espécies, a atividade metabólica foi avaliada por ensaio de redução 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-te­tra­zolium-5-carboxanilide com Menadiona, e a biomassa foi avaliada por coloração com Cristal Violeta 0,4% para posterior análise estatística. Resultados: Ambas as espécies de Candida foram capazes de formar biofilmes nos diferentes tipos de lentes de contato, havendo em lentes rígidas gás permeável maior atividade metabólica e menor biomassa formada. Conclusão: Esperava-se a obtenção de biofilmes de maior atividade metabólica e maior biomassa em lentes de contato gelatinosas com base no fundamento da Hidrofobicidade Superficial. Porém, o resultado apontou para maior atividade metabólica em lentes de contato rígidas. Apesar de observados resultados significativos, trata-se de um assunto de grande importância frente ao aumento do número de ceratites microbianas, mostrando-se necessários outros estudos para melhor elucidar a formação de biofilmes em diferentes tipos de materiais de lentes de contato.

Effectiveness of disinfecting substances of gutta-percha cones / Efetividade de agentes desinfectantes de cones de guta percha

Aim:To demonstrate the effectiveness of disinfecting substances with 2% and 5% Sodium Hypochlorite and 2% Chlorhexidine Gluconate at each of the pre-established times of 0:15 and 0:30 seconds, and 1, 2, 5, and 10 minutes. Methods: This study selected 96 gutta-percha cones that were contaminated with Enterococcus Faecalis, dried and treated with the aforementioned substances and applied at pre-established times. Subsequently, these were transferred to sterile Brain Heart Infusion broth and placed in a bacteriological incubator at 37°C for 24 hours to evaluate microbial growth, as well as in a nutrient agar medium in Petri dishes. Half of the cone was transferred to individual filter paper packages and exposed to the environment in a dental clinic at Universidade José do Rosário Velano, for 7 days, with subsequent evaluation for microbial growth. The bacterial phenotype test was performed using Gram stain and growth in 6.5% saline solution. The results were submitted to statistical analysis using the Kruskal Wallis H test, with a significance level of 5%. Results:The substances were effective at all times tested and individual storage supported disinfection. In the statistics test, the p-value was greater than 0.05, as there was no variability in the data configurations. Conclusion: The disinfection of gutta-percha cones and individual storage was an effective protocol to be adopted with 2% and 5% Sodium Hypochlorite and 2% Chlorhexidine.

Objetivo: Demonstrar a eficácia de substâncias desinfetantes, Hipoclorito de Sódio a 2% e 5% e Gluconato de Clorexidina 2% em cada um dos tempos pré-estabelecidos de 15 e 30 segundos, e 1,2, 5 e 10 minutos.Métodos: Este estudo selecionou 96 cones de guta-percha,contaminados com Enterococcus Faecalis, secos e tratados com as substâncias citadas e aplicadas em tempos pré-estabelecidos. Posteriormente, estes foram transferidos para tubos contendo caldo Infusão Cérebro Coração estéril e colocados estufa bacteriológica a 37°C por 24 horas para avaliar o crescimento microbiano, também verificado em meio ágar nutriente em Placas de Petri. Metade dos cones foram transferidos para embalagens individuais de papel de filtro, e expostas ao ambiente da clínica odontológica da Universidade José do Rosário Velano por 7 dias, com posterior avaliação do crescimento microbiano. O teste do fenótipo bacteriano foi realizado pela coloração de Gram e crescimento em solução salina a 6,5%. Os resultados foram submetidos à análise estatística por meio do Teste H de Kruskal Wallis, com nível de significância de 5%.Resultados: As substâncias foram eficazes em todos os tempos testados e o armazenamento individual favoreceu a desinfecção. No teste estatístico, o valor de p foi maior que 0,05, pois não houve variabilidade nas configurações dos dados.Conclusão: A desinfecção dos cones com Hipoclorito de Sódio 2% e 5% e Clorexidina 2% a partir de 15 segundos, e o armazenamento individual foram protocolos eficazes para serem adotados.

Candida glabrata among Candida spp. from environmental health practitioners of a Brazilian Hospital

Abstract The incidence of the species Candida albicans and non-albicans Candida was evaluated in a Brazilian Tertiary Hospital from the environment and health practitioners. In a 12-month period we had a total positivity of 19.65% of Candida spp. The most recurring non-albicans Candida species was C. glabrata (37.62%), generally considered a species of low virulence, but with a higher mortality rate than C. albicans. Subsequently, C. parapsilosis (25.74%) and C. tropicalis (16.86%) were the second and third most commonly isolated species. Considering the total samples collected from the emergency room and from the inpatient and the pediatric sector, 19.10% were positive for Candida spp., with the predominance of non-albicans Candida species (89.42%). The high percentage of positivity occurred in the hands (24.32%) and the lab coats (21.88%) of the health care assistants. No sample of C. albicans presented a profile of resistance to the drugs. All the non-albicans Candida species presented a decreased susceptibility to miconazole and itraconazole, but they were susceptible to nystatin. Most of the isolates were susceptible to fluconazole and amphotericin B. As expected, a high resistance rate was observed in C. glabrata and C. krusei, which are intrinsically less susceptible to this antifungal agent. The contamination of environmental surfaces by Candida spp. through hand touching may facilitate the occurrence of Candida infections predominantly in immunocompromised patients. In addition to that, the antifungal agents used should be carefully evaluated considering local epidemiologic trends in Candida spp. infections, so that therapeutic choices may be better guided.