Evaluation antibacterial and antibiofilm activity of the antimicrobial peptide P34 against Staphylococcus aureus and Enterococcus faecalis

ABSTRACT The adhesion ability of bacteria to abiotic surfaces has important implications in food industries, because these organisms can survive for long periods through the biofilm formation. They can be transferred from one place to another in the industry causing contamination of the food processing environment. In this study, the antibacterial and antibiofilm activities of the antimicrobial peptide P34, characterized as a bacteriocin-like substance (BLS P34) were tested against planktonic and sessile cells of Staphylococcus aureus and Enterococcus faecalis isolated from foods. The BLS P34 showed inhibitory effect against all planktonic cells of E. faecalis. The inhibition of biofilm formation and the eradication of pre-formed biofilm were evaluated with the crystal violet assay and with the reduction of 3-bromide [4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium. The BLS P34 promoted a reduction of percentage of adhered microbial cells on the surface, not being able to perform the complete elimination of biofilm formation. The metabolic activity of S. aureus biofilms decreased considerably between 41-95%. However, E. faecalis cells showed up metabolically stimulated. The BLS P34 has the potential antibiofilm for the species S. aureus. Studies suggest more detailed approaches to a better understanding of the interactions between the antimicrobial and bacterial cells within the biofilm structure.

Quantificação e identificação de Candida na cavidade oral de crianças / Quantification and identification of Candida in the oral cavity children

A identificação correta e precisa do agente causal de uma candidose é importante para a caracterização epidemiológica do tipo de infecção, como também para a escolha do tratamento. Os objetivos deste trabalho foram isolar, quantificar e identificar asleveduras do gênero Candida, presentes na cavidade oral de crianças de 2 a 4 anos de idade. Para a realização deste trabalho foram feitas coletas semanais em um grupo formado por dez crianças de 2 a 4 anos de idade, com o auxílio de swabs estéreis, friccionados na região periodental. O material coletado foi inoculado em meio cromogênico, utilizando-se a técnica de esgotamento e incubado a 36oC. A quantificação e identificação seguiram a metodologia descrita por Gwendolyn. Os resultados mostraram que, em 2.256 colônias isoladas, a C. albicans foi a mais frequente com 70,00; 70,44 e 95,15%, seguido pela C. tropicalis, com 16,99; 13,85 e 4,65%, C. glabrata com 11,77; 4,98 e 0,20%, respectivamente para 2, 3 e 4 anos de idade. A espécie que apresentou menor frequência foi a C. krusei com 1,24 e 10,73%, para 2 e 3 anos. Em crianças de 4 anos, não se verificou a presença dessa espécie .

The correct and precise identification of the causative agent of thrush is important for epidemiological characterization of the type of infection, but also for the choice of treatment. The objectives of this work was to isolate and quantify identify yeasts of the genus Candida in the oral cavity of children 2 to 4 years of age. For this work, samples were collected weekly in a group of ten children from 2 to 4 years old, and the samples were taken with sterile swabs, which were rubbed on the periodontal region. The collected material was inoculated on chromogenic medium, using the technique of exhaustion and incubated to 36 C. The quantification and identification followed the methodology described by Gwendolyn, (2005).The results showed that in 2256 isolated colonies, C.albicans was the most frequent with 70.00, 70.44 and 95.15%, followed by C. tropicalis, with 16.99, 13.85 and 4.65%, C. glabrata with 11.77, 4.98 and 0.20% respectively for 2, 3 and 4 years of age. The species that showed a lower frequency was C. krusei with 1.24and 10.73% for 2 and 3 years. In children aged 4 years, there was the presence of this species .