Summary
Background
Disinfectants with claimed activity against Clostridium difficile must be evaluated to ensure efficacy against the spores that comprise an environmental
source of patient infection. Unfortunately there is, at present, no generally accepted
method for evaluating these disinfectants. In the absence of such a method, laboratories
have to adapt protocols that were not designed for products used in medical environments
and consequently may use inappropriate test organisms, exposure times, and pass criteria.
Aim
To develop and evaluate a method for testing the activity of disinfectants against
C. difficile spores using exposure times and pass criteria which are relevant to clinical application.
Methods
A Joint Working Party of the Healthcare Infection Society (HIS) and the Advisory Committee
on Antimicrobial Resistance and Healthcare Associated Infections (ARHAI) of the Department
of Health in England was assembled. The Working Party adapted a previously described
enzyme-based method for spore purification (the Clospore method) using an exposure
time of 5min and a 5log10 kill as a pass criterion.
Findings
Evaluation of the method by three laboratories demonstrated that the method is simple
to follow and that the results are repeatable and reproducible.
Conclusion
The method described by the Working Party produces a clean suspension with a high
titre of spores. It is recommended that, for a disinfectant used in the environment,
the product should demonstrate a 5log10 reduction in 5min under clean or dirty conditions to fulfil the requirements of the test.
Keywords
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Article info
Publication history
Published online: October 24, 2014
Accepted:
September 22,
2014
Received:
September 15,
2014
Identification
Copyright
© 2014 The Healthcare Infection Society. Published by Elsevier Inc. All rights reserved.
