No description available.

No description available.

No description available.

The purpose of this research was to attempt to duplicate the in vitro bactericidal test against Pseudomonas aeruginosa as reported by Bjornson and Michael and to correlate agglutinating titer of an antiserum to protective activity.

No description available.

In recent years there has been renewed interest in the use of air ionisers to control of the spread of airborne infection. One characteristic of air ions which has been widely reported is their apparent biocidal action. However, whilst the body of evidence suggests a biocidal effect in the presence of air ions the physical and biological mechanisms involved remain unclear. In particular, it is not clear which of several possible mechanisms of electrical origin (i.e. the action of the ions, the production of ozone, or the action of the electric field) are responsible for cell death. A study was therefore undertaken to clarify this issue and to determine the physical mechanisms associated with microbial cell death. In the study seven bacterial species (Staphylococcus aureus, Mycobacterium parafortuitum, Pseudomonas aeruginosa, Acinetobacter baumanii, Burkholderia cenocepacia, Bacillus subtilis and Serratia marcescens) were exposed to both positive and negative ions in the presence of air. In order to distinguish between effects arising from: (i) the action of the air ions; (ii) the action of the electric field, and (iii) the action of ozone, two interventions were made. The first intervention involved placing a thin mica sheet between the ionisation source and the bacteria, directly over the agar plates. This intervention, while leaving the electric field unaltered, prevented the air ions from reaching the microbial samples. In addition, the mica plate prevented ozone produced from reaching the bacteria. The second intervention involved placing an earthed wire mesh directly above the agar plates. This prevented both the electric field and the air ions from impacting on the bacteria, while allowing any ozone present to reach the agar plate. With the exception of Mycobacterium parafortuitum, the principal cause of cell death amongst the bacteria studied was exposure to ozone, with electroporation playing a secondary role. However in the case of Mycobacterium parafortuitum, electroporation resulting from exposure to the electric field appears to have been the principal cause of cell inactivation. The results of the study suggest that the bactericidal action attributed to negative air ions by previous researchers may have been overestimated.

No description available.

Thesis (M.S.)--University of Wisconsin--Madison, 1947. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 44-48).

Neste trabalho foi testada a eficiência antimicrobiana de um nanocompósito de prata preparado a partir da modificação da resina comercial Lewatit VPOC1800 (contendo grupos sulfônicos) para três espécies de bactérias (Staphylococcus aureus, Pseudomonas aeruginosa e Escherichia coli.) cuja estrutura e composição das camadas externas da parede celular são distintas. Em termos da susceptibilidade aos biocidas essa diferença pode significar um fator importante de estudo. A avaliação da atividade biocida foi feita através de experimento que estimou a zona de inibição proporcionada pela atividade da resina sobre as bactérias estudadas. A resina mostrou eficiência biocida que aparentemente não é afetada pelas diferenças morfológicas das bactérias estudadas. Uma série de teste em batelada foi realizado com o intuito de se verificar a massa da resina e o tempo de contato ideal com a solução a ser descontaminada, chegando aos valores de 0,2g e 1minuto. As diferentes concentrações bacterianas utilizadas no estudo não influenciaram na atividade antimicrobiana da resina. Um estudo em coluna foi realizado para se averiguar o ponto de saturação do compósito, observando-se que a curva de ruptura da resina segue um tendência exponencial crescente igual a todas as espécies estudas, atingindo a saturação em aproximadamente 2250 mL / In this work, the bactericidal action of silver nanocomposite, prepared from the modification of the commercial resin Lewatit VPOC1800 (containing thiol group), was tested in three species of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli). The cellular structure and composition of those bacteria are different, influencing their reaction to the biocides, thus being an important factor of study. The evaluation of the biocidal activity was made through experiments that esteemed the area of inhibition in proportion to the activity of the resin on the target bacteria to be studied. The resin showed bactericidal activity on all the bacteria studied. Seemingly, the morphologic differences did not affect the bactericidal activity. A test series was performed with the intention of verifying the mass of the resin and the ideal time of contact with the solution to achieve descontamination. Values of 0,2g for 1min were observed. The different bacterial concentrations used in the study did not influence in the bactericidal activity of the resin. A study in column was accomplished to discover the point of saturation of the composite. We observed that the curve of rupture of the resin follows an exponential growth tendency, being the same for all the species studies, reaching the saturation in approximately 2250 mL

Neste trabalho foi testada a eficiência antimicrobiana de um nanocompósito de prata preparado a partir da modificação da resina comercial Lewatit VPOC1800 (contendo grupos sulfônicos) para três espécies de bactérias (Staphylococcus aureus, Pseudomonas aeruginosa e Escherichia coli.) cuja estrutura e composição das camadas externas da parede celular são distintas. Em termos da susceptibilidade aos biocidas essa diferença pode significar um fator importante de estudo. A avaliação da atividade biocida foi feita através de experimento que estimou a zona de inibição proporcionada pela atividade da resina sobre as bactérias estudadas. A resina mostrou eficiência biocida que aparentemente não é afetada pelas diferenças morfológicas das bactérias estudadas. Uma série de teste em batelada foi realizado com o intuito de se verificar a massa da resina e o tempo de contato ideal com a solução a ser descontaminada, chegando aos valores de 0,2g e 1minuto. As diferentes concentrações bacterianas utilizadas no estudo não influenciaram na atividade antimicrobiana da resina. Um estudo em coluna foi realizado para se averiguar o ponto de saturação do compósito, observando-se que a curva de ruptura da resina segue um tendência exponencial crescente igual a todas as espécies estudas, atingindo a saturação em aproximadamente 2250 mL / In this work, the bactericidal action of silver nanocomposite, prepared from the modification of the commercial resin Lewatit VPOC1800 (containing thiol group), was tested in three species of bacteria (Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli). The cellular structure and composition of those bacteria are different, influencing their reaction to the biocides, thus being an important factor of study. The evaluation of the biocidal activity was made through experiments that esteemed the area of inhibition in proportion to the activity of the resin on the target bacteria to be studied. The resin showed bactericidal activity on all the bacteria studied. Seemingly, the morphologic differences did not affect the bactericidal activity. A test series was performed with the intention of verifying the mass of the resin and the ideal time of contact with the solution to achieve descontamination. Values of 0,2g for 1min were observed. The different bacterial concentrations used in the study did not influence in the bactericidal activity of the resin. A study in column was accomplished to discover the point of saturation of the composite. We observed that the curve of rupture of the resin follows an exponential growth tendency, being the same for all the species studies, reaching the saturation in approximately 2250 mL