Mechanisms of sporicidal activity induced by ionized hydrogen peroxide in the inactivation of spores of Bacillus atrophaeus and Geobacillus stearothermophilus

• Ano de defesa: 2020
• Autor(a) principal: Grimaldo Lopez, Miguel Angel
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Peróxido de hidrogênio; DNA; Dano; Esporos de bactérias; Inativação; Bacillus atrophaeus; Geobacillus stearothermophilus; Biologia Molecular
• Link de acesso: https://locus.ufv.br//handle/123456789/28604

Ionized Hydrogen Peroxide (iHP) is a new technology used for the decontamination of surfaces or laboratory areas. It utilizes a low concentration of hydrogen peroxide (H 2 O 2 ) mixed with air and ionized through a cold plasma arc. This technology generates reactive oxygen species (ROS) as a means of decontamination. Although the technology has shown effectiveness in the inactivation of spores of biological indicators of Bacillus atrophaeus and Geobacillus stearothermophilus, its exact mechanism remains unknown. Therefore the purpose of this study was to determine the mechanism of inactivation utilized by iHP. The hypothesis of this research project was that the mechanism of sporicidal activity induced by ionized hydrogen peroxide was that it inactivates spores of B. atrophaeus and G. stearothermophilus by direct biochemical damage to the genomic DNA or by damage to essential germination factors that trigger the initiation of the spore germination and outgrowth process. To determine the exact mechanism, two pathways of inactivation were investigated. First, it was the visual verification with the use of a transmission electron microscope of the effects to the structure of the spores, and the second pathway was the verification of the impact by analyzing damages to the DNA of the spores by use of a SYBR green fluorescence- based quantitative polymerase chain reaction (qPCR). The uniform inactivation of B. atrophaeus and G. stearothermophilus and the reduction of the residual thermostable adenylate kinase (tAK) activity of enzyme indicators shows that iHP has a gas-like diffusion effect. Also direct biochemical damage to the genomic DNA was observed by the results of the visual and quantitative analysis. In conclusion, iHP inactivates spores by both physical damages of the spore structure and subsequent damage to the DNA. Keywords: Ionized Hydrogen Peroxide. DNA Damage. Inactivation of Spores. Bacillus atrophaeus. Geobacillus stearothermophilus.