Estudo da influência do substrato na atividade do Bacillus atrophaeus em indicadores biológicos autocontidos utilizados para monitorar sistemas de esterilização a óxido de etileno

Abstract

Biological indicators (BI) are to evaluate the effectiveness of sterilization processes through the introduction of highly resistant bacterial spores in the sterilization cycle. Bacillus atrophaeus is used for monitoring the sterilization ethylene oxide gas systems, and when these spores are destroyed, can ensure that contaminating microorganisms were killed load thereby ensuring the sterility of the material. Therefore, this work aimed to study the influence of the concentration of glucose and protein (TSB), as well as the pH indicator bromothymol blue in the activity B. atrophaeus in self-contained biological indicators used in monitoring of sterilization systems for ethylene oxide gas. To this end, it was evaluated the influence of nutrient glucose and TSB present in the culture medium of the IB, as well as the pH indicator bromothymol blue, with levels of 2.5, 3.25 and 5.0 g / L for glucose, 5.0, 7.5 and 10.0 g / L TSB, and 0.05, 0.10 and 0.15 g / L bromothymol blue. Was used an experimental design of Box-Behnken for 3 variables, where the model evaluates the effect of each independent variable for an answer. The tests were subjected to colorimetric analysis and evaluation time of turning. For analysis of the results it is concluded that the combination of concentration of variables really is able to influence the color of the turning and the time of the turning of IB; may be suggested that, for best results in color intensity turning and turning in time should employ the ideal combination verified: higher concentrations for glucose, low concentrations to TSB and intermediate concentration for bromothymol blue; among combinations and concentrations evaluated in this work.