Antimicrobial activity of a chlorhexidine intravascular
catheter site gel dressing
Tarja J. Karpanen1, Anna L. Casey1, Barbara R. Conway2,3, Peter A. Lambert2and Tom S. J.Elliott4*
1Department of Clinical Microbiology and Infection Control, University Hospitals Birmingham NHS Foundation Trust, UK;
2Life and Health Sciences, Aston University, Birmingham, UK;3School of Applied Sciences, University of Huddersfield, Huddersfield, UK;
4Corporate Division, University Hospitals Birmingham NHS Foundation Trust, UK
*Corresponding author. Tel: +44-121-371-4729; Fax: +44-121-414-1682; E-mail: firstname.lastname@example.org
Received 25 January 2011; returned 28 February 2011; revised 11 April 2011; accepted 19 April 2011
Objectives: The antimicrobial efficacy of a chlorhexidine gluconate (CHG) intravascular catheter gel dressing
was evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and an extended-spectrum b-lacta-
mase (ESBL)-producing Escherichia coli. Chlorhexidine deposition on the skin surface and release from the gel
Methods: The antimicrobial efficacy was evaluated in in vitro studies following microbial inoculation of the dres-
sing and application of the dressing on the inoculated surface of a silicone membrane and donor skin [with and
without a catheter segment and/or 10% (v/v) serum] on diffusion cells. Antimicrobial activity was evaluated for
up to 7 days. Chlorhexidine skin surface deposition and release were also determined.
Results: MRSA and E. coli were not detectable within 5 min following direct inoculation onto the CHG gel dres-
sing. On the silicone membrane, 3 log and 6 log inocula of MRSA were eradicated within 5 min and 1 h, respect-
ively. Time to kill was prolonged in the presence of serum and a catheter segment. Following inoculation of
donor skin with 6 log cfu of MRSA, none was detected after 24 h. Chlorhexidine was released from the gel
after a lag time of 30 min and increasing amounts were detected on the donor skin surface over the 48 h
test period. The CHG gel dressing retained its antimicrobial activity on the artificial skin for 7 days.
Conclusions: The CHG intravascular catheter site gel dressing had detectable antimicrobial activity for up to
7 days, which should suppress bacterial growth on the skin at the catheter insertion site, thereby reducing
the risk of infection.
Keywords: catheter-related infections, antisepsis, ex vivo, Franz diffusion cell
Intravascular catheters are associated with a high risk of infec-
tion, which includes both superficial skin infection at the site of
insertion and bloodstream infection. Recent approaches to
reduce the risk of catheter-related infections (CRIs) include
improved skin antisepsis, use of antimicrobial catheters and
innovative catheter site dressings.1,2Some of these approaches
have been incorporated into guidelines. These include the UK
EPIC2 guidelines (Evidence-based Guidelines for Preventing
Healthcare Associated Infections),2care bundles (Department
of Health Central Venous Catheter Care Bundle, High Impact
Intervention No. 1)3and, more recently, the Matching Michigan
strategy.4,5However, despite these initiatives, CRI still occurs
and further innovations to reduce CRI are required.
Appropriate skin antisepsis to reduce the number of microor-
ganisms on the skin prior to carrying out an invasive procedure is
critical, as it decreases the risk of subsequent infection. However,
skin antisepsis does not eradicate all the microorganisms associ-
ated with the skin. This is probably related to the limited skin per-
meation of antiseptics and the presence of microorganisms
residing in the deeper layers of the skin.6–10The persisting micro-
organisms in the skin layers may act as a nidus to contaminate
the catheter, particularly at the time of insertion, and could
result in either localized or systemic infection.11,12The interaction
between antiseptics and skin flora is complex and involves other
confounding factors. For example, microorganisms may also
reside in the skin in aggregates or microbial biofilms,13,14and
low concentrations of antiseptics, such as chlorhexidine and
alcohol, may encourage biofilm formation.15–17It is therefore
evident that adequate concentrations of antiseptics are required
at a central venous catheter (CVC) insertion site to maximize the
antiseptic activity, which in turn may prevent catheter coloniza-
tion and reduce the risk of CRI.
# The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.
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J Antimicrob Chemother 2011; 66: 1777–1784
doi:10.1093/jac/dkr191 Advance Access publication 24 May 2011
by guest on December 28, 2015
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Karpanen et al.
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