Effect of combination of Oxyrase and sodium thioglycolate on growth of Clostridium perfringens from spores under aerobic incubation

摘要

Clostridium perfringens is a strictly anaerobic pathogen that requires absence of oxygen for its growth in laboratory experiments, which is usually attained by using an anaerobic chamber or anaerobic jars. However, it has been demonstrated that C. perfrtngens may survive for short periods of times due to its adaptive response to O_2. Therefore, the objective of this study was to explore the application of Oxyrase (OX) and sodium thiogly-colate (ST) as oxygen scavengers, used alone or in combination, for observation of the growth of C. perfrtngens under aerobic incubation. The growth of C. perfrtngens from spores in Schaedler Anaerobe Agar containing different levels and combinations of OX and ST was observed at temperatures between 20 and 50 ℃. The kinetic parameters, including lag time, specific growth rate, and maximum cell concentrations in the stationary phase, were determined. The results indicated that ST at concentrations of 0.025 and 0.05% (w/w), although allowing eventual growth of C. perfrtngens, prolonged its lag times, while OX at 1.5% only allowed growth at a lower growth rate in comparison to anaerobic incubation. OX at 3% enhanced the growth of C. perfrtngens at temperatures between 30 and 50 ℃, while higher levels of OX were needed in the medium to support the growth of C. perfrtngens during storage at 25 ℃ (> 6% OX) and 20 ℃ (> 9% OX), due to the effect of temperature on enzyme activity. No significant difference was found in the kinetic parameters of C. perfrtngens incubated aerobically with OX and the control (without OX or ST) in an anaerobic chamber. Therefore, OX at appropriate concentrations may allow the observation of the growth of C. perfrtngens under aerobic incubation conditions without the need of an anaerobic device.