Author: Leong, Weng Si Priscilla
Title: The transmission of bacteria acquired from handwashing with contaminated soaps : a simulated clinical field experimental study
Degree: M.Sc.
Year: 2014
Subject: Hand washing.
Medical personnel -- Health and hygiene.
Hong Kong Polytechnic University -- Dissertations
Department: School of Nursing
Pages: xi, 68 leaves : col. ill. ; 30 cm.
Language: English
Abstract: Background: Liquid soaps are prone to extrinsic bacterial contamination. Performing hand hygiene practices with contaminated soap may reduce the efficacy of the original purposes. Several previous studies reported that uses of contaminated soaps were linked to outbreaks in health-care settings. Aim: This study is aimed to investigate the cause-and-effect on cross-transmission of bacteria on hands acquired from handwashing with contaminated soaps using an approach of simulated clinical field experiments. Methods: The study included one controlled hand washing experiment and two transmission tests. The Controlled Hand Washing Experiment was a laboratory experimental study. Subjects performed handwashing with non-contaminated soaps (control group) and contaminated soaps (test group). The subjects were requested to perform the above process twice by using different hand drying methods each time (hand dried by sterile paper towel or by shaking off the excess water). Glove juice method and hand stamp method were applied to recover the bacterial counts from the subjects' hands. Seventeen subjects participated in this experiment and randomly assigned into three different groups, (1) six subjects handwashed with high level contaminated soaps (8.15-8.23 log10 CFU/ml) and non-contaminated soaps; (2) six subjects handwashed with moderate level contaminated soaps (5.72-5.83 log10 CFU/ml) and non-contaminated soaps; (3) five subjects handwashed with low level contaminated soaps (2.65-3.82 log10 CFU/ml) and non-contaminated soaps. The Transmission test I and II were a field experimental study. Subjects performed handwashing with non-contaminated soaps (control group) and contaminated soaps (test group). After handwashing, subjects performed the nursing procedures on a dummy patient with either direct (Test I) or indirect contacts (Test II). Sterile cotton swab method was applied to recover the bacterial counts from the target surface spots of dummy patient as well as the medical instrument and glove juice method was applied to recover the bacterial counts from the subjects' hand after performing nursing procedures. Each transmission test had twelve subjects participated and randomly assigned into two different groups, (1) nine subjects hand dried by sterile paper towel; (2) three subjects hand dried by shaking off the excess water. Serratia marcescens was used as a marker microorganism in this study. Different levels of contaminated soaps were prepared artificially by inoculating 500ul to 10ml of Serratia marcescens (source of contamination).
Results: The results in controlled hand washing experiment showed that the bacteria in the contaminated soaps could be residuals on subjects' hands after handwashing with contaminated soaps. There were statistically significant difference (p<0.05) between handwashing with contaminated soaps and non-contaminated soaps in following handwashing combinations: Low (by sterile paper towel) (p=0.039), Moderate (by shaking off the excess water) (p=0.027), High (by sterile paper towel) (p=0.028) and High (by shaking off the excess water) (p=0.028). The results in controlled hand washing experiment also showed that the bacteria acquired from handwashing with contaminated soaps could be further transferred to the surface of the agar plates. There were statistically significant difference (p<0.05) between handwashing with contaminated soaps and non-contaminated soaps in following handwashing combinations: Moderate (by shaking off the excess water) (p=0.026), High (by sterile paper towel) (p=0.014) and High (by shaking off the excess water) (p=0.014) The results in two transmission tests showed that the bacteria acquired from handwashing with contaminated soaps could be further transferred to the target surface spots of dummy patient through nursing procedures require direct and indirect contacts. However, the numbers of bacteria transferred were small and the results were not statistically significant difference (p>0.05) between handwashing with contaminated soaps and non-contaminated soaps in all handwashing combinations (p values ranged from 0.209 to 0.317). Conclusion: The results in two transmission tests were not statistically significant difference. Therefore, the null hypothesis was not rejected. However, the results still indicated that small number of bacteria transferred occurred through performing patient care activities on a dummy patient. Hence, handwashing with contaminated soaps would become a potential risk factor of spreading of pathogenic microorganisms in health-care environments through the health-care workers. Health-care workers should raise the awareness on the choice of hand hygiene agents and the conditions of the hand hygiene facilities. Hospital administrators should make sure to put enough attention to monitor and review the hand hygiene policy regularly.
Rights: All rights reserved
Access: restricted access

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