Author: Yip, Chui Yee Megan
Title: Effectiveness of disinfectants against Clostridium difficile
Advisors: Leung, Polly (HTI)
Degree: M.Sc.
Year: 2016
Subject: Clostridium difficile.
Disinfection and disinfectants.
Hong Kong Polytechnic University -- Dissertations
Department: Department of Health Technology and Informatics
Pages: xiii, 60 pages : color illustrations
Language: English
Abstract: Background: The incidence of hospital acquired infections has dramatically increased for the past several decades (Chen et al, 2013). Clostridium difficile is one of the most common causes of nosocomial diarrhea, its spores can persist on surfaces for several months and some of the strains are shown to be resistant to widely used disinfectants under certain conditions. It is necessary to implement appropriate prevention and determine the most effective disinfectant for destroying both the vegetative cells and spores in order to control the spread of pathogen to other hospitalized patients and healthcare workers. Aims and scopes of this project: The purpose of this study was to investigate the effectiveness of disinfectants, Clorox and Cidex OPA against Clostridium difficile spores, aim to minimize the spread of Clostridium difficile infection by raising awareness on proper use of disinfectant. Methods: The effectiveness of disinfectants, Clorox and Cidex OPA were tested against 12 spore samples for this research project. 7 samples were PCR ribotype 002, 2 samples were PCR ribotype 012, and others were PCR ribotype 010, 027 and PRO 6973. All samples were challenged with different working concentration of disinfectants for two time intervals to determine the minimum sporicidal concentration. In addition, the efficacy of disinfectants was tested in the presence and absence of organic matter followed by investigation of decontamination level of different surfaces.
Results: Based on the results, both Clorox and Cidex OPA were very effective for destroying the spores of different ribotypes at concentration below the manufacturer's recommendation Clorox and Cidex OPA remained active at 80 fold and 2 fold dilution, respectively. Furthermore, Clorox was found to be the most effective at 1:2 dilution which is once again below the manufacturer's recommendation as it was able to bring over 2 log reduction at both time intervals with or without organic matter whereas Cidex OPA was able to bring a 2 log reduction at its manufacturer's recommendation. Both agents did not show any significant difference between the presence and absence of organic matter (p value>0.05). However, when Clorox was diluted to 100 fold, it was only able to eliminate the spores to some extent on the floor tiles and stainless steel surfaces but the log reduction at 50 fold dilution was significantly increased. Conclusion: The proper use of disinfectant could be one of the major factors in preventing the transmission of Clostridium difficile infection in the developed countries. All infectious control personnel should raise awareness on the importance of the efficacy of disinfectant in addition to the existing protocols such as following proper hand hygiene techniques in between patients, appropriate cleaning of all medical equipment and wear proper protective clothing. Furthermore, it is necessary to update the manuals for the control of CDI periodically as current studies have demonstrated that Clostridium difficile appears to be evolving and presented some strains of Clostridium difficile seems to be more resistance to decontaminating agents than the others.
Rights: All rights reserved
Access: restricted access

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