An evaluation of three biological indicator systems in flash sterilization

Area of Science:

• Sterilization and Infection Control
• Microbiology
• Biomedical Engineering

Background:

• Biological indicators (BIs) are critical for verifying sterilization efficacy.
• Flash sterilization requires specific BIs to ensure rapid and reliable monitoring.
• Assessing BI sensitivity and reliability is crucial for patient safety.

Purpose of the Study:

• To evaluate the sensitivity and reliability of two flash-sterilization-specific biological indicators (BIs) and one traditional spore strip.
• To compare the survive/kill ratios of 3M Attest #1261, Amsco Proof Flash, and Castle Tec Test.
• To determine the most satisfactory BI for monitoring three-minute flash sterilization cycles.

Main Methods:

• Tested BIs included 3M Attest #1261, Amsco Proof Flash, and Castle Tec Test.
• Exposure times ranged from zero (come-up time) to three minutes at 273°F in a gravity displacement sterilizer.
• Survival was assessed by media color change or turbidity after incubation at 55°C; cycles were replicated.

Main Results:

• Amsco Proof Flash exhibited technical difficulties, including vial crushing issues and media evaporation.
• Castle Tec Test showed insufficient resistance, with no survivors detected at any exposure time.
• 3M Attest #1261 demonstrated 100% survival at 0 and 1-minute exposures, 94% at 2 minutes, and 0% at 3 minutes.

Conclusions:

• 3M Attest #1261 was more satisfactory in monitoring three-minute flash sterilization cycles than Proof Flash and Tec Test.
• Proof Flash and Tec Test exhibited limitations in sensitivity and reliability for flash sterilization monitoring.
• Independent evaluation of BIs by healthcare institutions is recommended for optimal use.