Journal of Community Nursing - page 29

2013,Vol 27, No 4
bacterial cell death. They bind to
bacterial cell membranes, causing
disruption of the bacterial cell wall
and cell leakage. Once transported
into the cell, silver ions interrupt
the cell’s function by binding to
proteins and interfering with energy
production, enzyme function and
cell replication (Lansdown, 2002;
Hermans, 2007).
Silver ions are active against
a broad range of bacteria, fungi
and viruses, including many
antibiotic-resistant bacteria, such
as MRSA and vancomycin-resistant
Enterococci (VRE) (Parsons et al,
2005). Studies have suggested that
silver may reduce bacterial adhesion
and destabilise the biofilm matrix
(Chaw et al, 2005), as well as killing
bacteria within the matrix. Silver
dressings represent one in seven of
all wound dressing prescriptions in
the UK (Iheanado, 2010).
Iodine-based products have been
used in wound care for many
years. Exposure of bacteria to
iodine causes changes in cells’
walls, membranes and cytoplasm,
resulting in rapid death (Gottardi,
1983) through leakage of cellular
materials (Schreier et al, 1997).
Povidone-iodine is not as
effective as some other biocides in
Staphylococcus epidermidis
biofilms (Presterl
et al, 2007), but cadexomer iodine
provides enough iodine for biofilm
suppression while not causing
significant host damage (Akiyama et
al, 2004; Rhoads et al, 2008).
The antibacterial action of honey
is due to its high osmolarity, which
inhibits microbial growth (Molan,
2001), and the action of intrinsic
enzymes, which release hydrogen
peroxide into the wound (Molan
and Betts, 2004). Some honeys,
particularly the manuka honeys,
have been found to retain their
bactericidal properties even without
the presence of hydrogen peroxide,
and are effective against both
antibiotic-sensitive and antibiotic-
resistant organisms (Cooper et al,
2002a; 2002b).
Although the use of PHMB is
widespread in German-speaking
Europe and the US, these dressings
are a relatively new development
in the UK’s wound management
armoury. PHMB is a fast-acting
biguanide compound composed
of a synthetic mixture of polymers.
It has a broad spectrum of activity
against bacteria, viruses and fungi,
inducing cell death by disrupting
cell membrane integrity (Moore and
Gray, 2007).
However, PHMB does not
interfere with the proteins that
make up animal cell membranes
and has an effect on both
planktonic bacteria and those
in biofilms (Seipp et al, 2005;
Pietsch and Kraft, 2006; Harbs
and Siebert, 2007). A significant
body of evidence is now emerging
to support PHMB’s use in the
management and eradication of
wound bioburden (Butcher, 2012).
antimicrobial dressings (Bergin
and Wraight, 2006; Chaby et al,
2007; Michaels et al, 2009), and
their safety in respect to the
systemic absorption of antimicrobial
elements and potential for systemic
toxicity (Wan et al, 1991; Parsons et
al, 2005; Burd et al, 2007; Denyer,
2009; Wang et al, 2009).
The results of studies such as
theVULCAN trial (Michaels, 2009),
which appear to indicate that silver-
based antimicrobial products are
not cost-effective, have added to
this controversy, although alleged
methodological flaws in this particular
study have led to widespread criticism
of its recommendations (Calderon et
al, 2007; Gottrup and Apelqvist,
2010; Leaper and Drake, 2010; White
et al, 2010).
To date, however, there has
been no conclusive evidence
that, when used appropriately,
topical antimicrobial dressings
pose a significant risk. Thus,
to aid clinicians a number of
recommendations for safe use
have been developed (Bowler et al,
2001; EWMA, 2006; Best Practice
Statement, 2011; International
Consensus, 2012).
Most importantly,
antimicrobial use should be
targeted to those at most risk or in
whom wound infection has been
diagnosed. Treatment should also
be measured and time-limited
— widespread, inappropriate use
increases healthcare costs with no
outcome gain.
Once initiated, if the signs of
infection subside and the patient
shows no signs of systemic
infection, the antimicrobial agent
may be discontinued. If the
wound continues to show signs
of infection, a systemic antibiotic
should be considered (EWMA,
2006). Similarly, a lack of a
noticeable healing response within
two weeks may necessitate the use
of other topical or systemic agents
(Bowler et al, 2001; Best Practice
Statement, 2011).
The prophylactic use of
antimicrobial preparations is
‘The antibacterial action
of honey is due to its high
osmolarity, which inhibits
microbial growth.’
Dialkyl carbamoyl chloride
An alternative approach to
bioburden management is offered
by products containing dialkyl
carbamoyl chloride (DACC)
technology. DACC is a fatty
acid derivative, which is applied
to dressing materials during
manufacture. It provides the dressing
with strongly hydrophobic properties
— bacteria become irreversibly
bound to the wound dressing itself,
preventing them from proliferating
or releasing harmful exotoxins. At
each dressing change inert bacteria
are removed from the wound bed
along with the dressing product,
thus reducing the bacterial load
(Cutting and Butcher, 2011).
Recently, concern has been
raised regarding the cost and
cost-effectiveness of topical
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