In a study published in The American Journal of Ophthalmology on June 15, 1985, researchers investigated the susceptibility of Acanthamoeba, a free-living amoeba known for causing keratitis and granulomatous amoebic encephalitis, to various surgical instrument sterilization techniques.
The study compared autoclaving, steam sterilization, and dry heat sterilization on Acanthamoeba castellanii trophozoites at 15 pounds per square inch (psi) and 121 degrees Celsius for 15 minutes, 134 degrees Celsius for 3 minutes, and 176 degrees Celsius for 1 hour respectively.
The results demonstrated that all three sterilization techniques were capable of completely eliminating Acanthamoeba from the inoculated surfaces when using the specified conditions. However, the study highlighted that dry heat sterilization at 160 degrees Celsius for 2 hours was found to be more effective compared to autoclaving and steam sterilization.
The research took place in a hospital Central Service Department (CSSD), employing standardized protocols for instrument handling, inoculation, and culture methods, adhering to guidelines set by the Association for the Advancement of Medical Instrumentation (AAMI) and the Centers for Disease Control and Prevention (CDC).
The findings suggest that surgical instruments should undergo a sterilization cycle with dry heat at 160 degrees Celsius for at least 2 hours to ensure complete eradication of Acanthamoeba. This information could be particularly relevant for healthcare facilities that utilize dry heat sterilizers for instrument decontamination in settings such as ophthalmology