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- Title
ELABORACIÓN Y CONTROL DE CALIDAD DE TIRAS DE ESPORAS (SPORE STRIPS) CASERAS PARA MONITOREAR PROCESOS DE ESTERILIZACIÓN.
- Authors
VALENCIA TUSA, Israel Alejandro; GUERRA, David; ECHEVERRÍA, Gustavo; RODRÍGUEZ HILDALGO, Richar; TERÁN, Rommy; de WAARD, Jacobus H.
- Abstract
Background: Biomarkers, especially spore strips, are used to evaluate sterilization processes. Spore strips are not readily available in Ecuador and are expensive (US$ 2). In this investigation we develop homemade strips with a mixture of bacillus species which can be used to evaluate different sterilization processes. Objectives: To prepare homemade spore strips which can be used for the validation of steam sterilization, ethylene gas, dry heat sterilization and formaldehyde fumigation. To determine the quality of the isolated spores (D- value and Z-value) and compare the performance of the home made strip with a commercial available strip. Methods: Spores of Bacillus atrophaeus ATCC 9372, B. subtilis 9372 and Geobacillus stearothermophilus ATCC 7953 were produced by seeding the strains in Petri dishes with Nutrient Agar. Plates were incubated for 10 days at 37°C (56°C for G. stearothermophilus). Spores were harvested by washing the plates with sterile water. Vegetative cells were inactivated, incubating the spore suspension for 20 minutes at 80 °C. Spores were quantified (UCF) and stored at 4 °C in 40% ethanol. "Spore strips" were prepared by inoculating sterile filter paper of 3x0.5 cm with 106 spores of Bacillus subtilis, 105 Geobacillus stearothermophilus and 106 of Bacillus atrophaeus. For use, the strips were fitted in a paper envelope of approx. 3.5x1 cm. The D- and Z-values of spores isolated from the Bacillus species were determined at temperatures of 120 and 130 °C. For quality control, strips were incubated in a dry heat oven at 170 ° C along with a commercial strip for different times (5, 10, 30, 50, 60 minutes). Each strip was cultured and the temperature resistance of homemade strips was compared with the commercial strips. The strips made in our laboratory proved to be more resistant to heat (approximately a 20 minutes increase) than the commercial strip. Conclusions: We show a simple method for the elaboration of a combined species spore strip that can be used for the monitoring of different sterilization processes. Our strips have at least the same quality as a commercial spore strip that has been elaborated under ISO norms.
- Publication
Vitae (01214004), 2016, Vol 23, pS106
- ISSN
0121-4004
- Publication type
Article