Fundamental aspects in the validation of the biological monitor for sterilization by ethylene oxide / Aspectos fundamentais na validação do monitor biológico para a esterilização por óxido de etileno

AUTOR(ES)
DATA DE PUBLICAÇÃO

1991

RESUMO

This study intended to standardize some of the important elements of biological indicators, taken in consideration the importance of sterility assurance of medical devices and knowing the necessity of Ethilene Oxide sterilization process control throught several parameters, among them the biological sensor. Spores of Bacillus .subtilis var. niger, were produced in chemically defined liquid and solid sporulation media, as well as purchased as suspension from local suppliers. The biological indicators were obtained after being inoculated on paper, aluminum foil and plastic carriers following by wrapping on protective packaging. In parallel biological indicators in paper carriers, purchased from local market and from United States suppliers were also tested. The variables considered on preparation of the biological monitors were: the nature of the carriers and packages used and the dimension of the test specimens. Twenty seven individual groups of biological monitors have been prepared, being 19 on paper carrier, 4 into aluminum foil and 4 into plastic, bringing to 3 multiple groups. The evaluation of the nature of the carrier on the spore resistance was done through the challange of the biological monitors to sub-lethal cycles, followed by lethality study and D value calculation. Within the 19 groups on paper carrier no significant statistical difference was observed in respect to spores resistance to the sterilization agent, in spite of the various sources of the spores, with respect to the sporulation stage, no matter the nature of culture media, the cycle or the generating laboratory, or even bioindicators from distinct manufacturers. There was an significant statistical difference on spores resistance between paper and plastic carriers. In respect to the gas sterilization effectiveness across packages of different nature, biological monitors were tested containing bioindicators in paper carriers, after their exposure to sub-lethal cycles. The D values obtained made patent the compatibility of distinct packages to ethilene oxide sterilization provided the porosity caracteristics are respected. In an additional group of biological, monitors, using paper as carrier and on that the dimension of the test specimens was the variable considered the sterilization process was an industrial cycle, followed by a surviving spores recovery through the carriers inoculation into thioglicolate broth, soybean-casein broth and also the last broth added with bromothymol blue. The growing promoting capacity of those 3 media did not show differences. The sterilization effectiveness was dependent to the dimension of the test specimens. The periodic determination of residual gas content on the test specimens, as well as the industrial environment monitoring denote the need and importance of the legislation in force, being imperative full compliance to the same.

ASSUNTO(S)

esterilização monitor biológico sterilization biological monitor indicador biológico Óxido de etileno ethylene oxide biological indicator

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