Background
A biofilm is a complex microbiological ecosystem deposited on surfaces. Microorganisms
in form of biofilms are of particular clinical concern because of the poor response
to antimicrobial treatments. This study aimed to determine whether bacterial and fungal
biofilms are able to resist the antimicrobial activity of chlorhexidine, a powerful
antiseptic widely used in the hospital environment.
Methods
Disk diffusion and susceptibility tests were conducted in accordance with Clinical
and Laboratory Standards Institute standards for the determination of biofilm inhibitory
concentration. Chlorhexidine was tested first at a minimum inhibitory concentration
and then at higher concentrations when it was not able to destroy the biofilm. The
plates were developed with a solution of 0.1% crystal violet, and readings were made
at an optical density of 570 nm.
Results
Chlorhexidine demonstrated excellent antimicrobial activity for most microorganisms
tested in their free form, but was less effective against biofilms of Acinetobacter baumannii, Escherichia coli, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa.
Conclusion
This study confirms that microorganisms in biofilms have greater resistance to chlorhexidine,
likely owing to the mechanisms of resistance conferred to the structure of biofilms.
Key Words
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Article info
Publication history
Published online: August 05, 2013
Footnotes
Conflict of interest: None to report.
Identification
Copyright
© 2013 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
