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A Method to Test the Efficacy of Handwashing for the Removal of Emerging Infectious Pathogens
Published on: June 7, 2017
Simulated microbe removal around finger rings using different hand sanitation methods
Archana A Alur1, Madhavi J Rane, James P Scheetz
1Ballard High School, Louisville, Kentucky, USA.
Aim:
It is our opinion that the CDC and the WHO have underestimated cross-contamination under examination gloves in dental clinics while wearing jewelry, such as finger rings. These agencies only "recommend" removing jewelry, and only washing hands for 15 seconds with soap and warm water before donning gloves. This study examined several washing procedures and finger rings using simulated microbes.
Methodology:
A gloved rubber hand manikin was made and fitted with a fresh disposable vinyl glove. Four fingers were fitted with rings or no ring, dusted with simulated microbes, and washed with a scrub brush for 5, 15, and 25 seconds under 20 degrees C and 40 degrees C water alone, or with liquid hand soap. Light levels (in lux) of fluorescent powder before and after washing were measured and delta scores calculated for changes in light levels, equivalent to effectiveness of hand washing procedures. A full-factorial, 3-factor analysis of variance (ANOVA) was used to test for differences among levels of the three study factors-time, temperature, and soap use. Tukey's post hoc honestly significant difference (HSD) test was applied to significant factors to examine pair-wise differences between factor levels.
Results:
It was found that the longer the hands with rings were washed with a scrub brush under flowing water, the more simulated microbes were removed. By 25 seconds, all methods were essentially the same. Simulated microbes were more difficult to remove from the palm compared to the back of the hand. The liquid hand soap used in this study was more effective with warm water than cold. When given a choice of washing with cold water up to 15 seconds, it would be preferable not to use soap to remove simulated microbes. Qualitatively, the outer surface of finger rings were more effectively cleaned than the crevice below the ring, and the ring with a stone setting appeared to accumulate and retain simulated microbes more than other rings.
Conclusion:
The most effective treatment was washing with warm water and liquid soap. Longer times were more effective. Rings should not be worn under examination gloves due to difficulty cleaning in the crevice under the ring, and the well-known consequences of cross-contamination between the patient and the health care worker.
Insights
Wearing jewelry like finger rings increases the risk of microbial contamination under examination gloves. Thorough handwashing with warm water and soap for longer durations is crucial to minimize this risk in dental settings.
Area of Science:
- Infection Control
- Microbiology
- Public Health
Background:
- Current guidelines from the Centers for Disease Control and Prevention (CDC) and the World Health Organization (WHO) may underestimate the risk of cross-contamination associated with wearing jewelry, such as finger rings, under examination gloves in dental clinics.
- Recommendations for hand hygiene before donning gloves, including washing for 15 seconds with soap and warm water, may not be sufficient to eliminate microbial load when jewelry is present.
Purpose of the Study:
- To evaluate the effectiveness of different handwashing procedures and the impact of finger rings on the removal of simulated microbes from gloved hands.
- To provide evidence-based recommendations for hand hygiene practices in dental settings to mitigate cross-contamination risks.
Main Methods:
- A simulated microbial contamination model using a gloved rubber hand manikin was employed.
- Washing procedures varied in duration (5, 15, 25 seconds), water temperature (20°C, 40°C), and the use of liquid hand soap.
- Fluorescent powder was used to simulate microbes, and light levels before and after washing were measured to quantify microbial removal effectiveness. Statistical analysis included a full-factorial ANOVA and Tukey's HSD test.
Main Results:
- Increased washing time with a scrub brush under flowing water effectively removed more simulated microbes, with all methods showing similar results by 25 seconds.
- Warm water combined with liquid hand soap demonstrated superior microbial removal compared to cold water.
- Simulated microbes were more difficult to remove from the palm than the back of the hand. Finger rings, especially those with stone settings, accumulated and retained microbes more effectively in crevices.
Conclusions:
- The most effective hand hygiene protocol involved washing with warm water and liquid soap for extended periods.
- Wearing finger rings under examination gloves should be discouraged due to the challenges in cleaning the sub-ring area and the significant risk of patient-to-healthcare worker cross-contamination.
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