An evaluation, using computerized image analysis, of antimicrobial efficacy of an automatic hand washing machine with ultrasonic wave spraying

Area of Science:

• Microbiology
• Infection Control
• Biomedical Engineering

Background:

• Hand hygiene is crucial for preventing infections.
• Novel methods for rapid and effective hand sanitization are continuously sought.
• The TE-KIREIKI quick-dry hand washing machine utilizes ultrasonic wave spraying with an alcohol-based product, AROKULIN-E.

Purpose of the Study:

• To assess the antimicrobial efficacy of the TE-KIREIKI hand washing machine combined with AROKULIN-E.
• To compare the bacterial reduction achieved by a short-duration alcohol-based wash versus a longer soap-and-water wash.
• To determine if the tested hand hygiene methods eradicate bacteria from the hand surface.

Main Methods:

• Ten male subjects abstained from antimicrobial agents and hand soap prior to the study.
• Palm prints were taken on agar plates before and after hand washing.
• Bacterial colonies were quantified using the ASPECT image processing system after 48-hour incubation at 37°C.

Main Results:

• Hand washing pattern A (3-second wash with AROKULIN-E) resulted in a 49.1% bacterial reduction.
• Hand washing pattern B (30-second wash with nonmedicated soap and water, plus pattern A) resulted in a 51.3% bacterial reduction.
• Neither hand washing pattern demonstrated complete eradication of bacteria.

Conclusions:

• The tested quick-dry hand washing machine with ultrasonic wave spraying and AROKULIN-E shows moderate but insufficient antimicrobial efficacy.
• Current protocols do not effectively eliminate hand surface bacteria.
• Further improvements to the hand washing machine's technology or protocol are necessary for adequate bacterial reduction.