Silver
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It is perhaps not strictly appropriate to discuss the use of silver as an alternative to antibiotics, because silver functions really as an antiseptic biocide more like chlorhexidine or povidone-iodine.
SILVER
It is perhaps not strictly appropriate to discuss the
use of silver as an alternative to antibiotics, because
silver functions really as an antiseptic biocide more like
chlorhexidine or povidone-iodine. However,
some reviews have discussed it in this context
and so it is included here for completeness.
Silver has of course been used over centuries to treat
and prevent infections, and like some
of the other forms of treatment described
in this chapter, its use
decreased with the advent
of antibiotics. In the form of
silver sulphadiazine, however, it has been
a mainstay in the treatment of wound, particularly
burn, infections for the last 40 years
and this is likely to continue. In addition, the number of wound dressings containing silver as an
antimicrobial component is increasing. Despite
this, there are a limited number
of conclusive clinical
trials attesting to their efficacy and this situation certainly needs to be addressed.
Silver can generate a number of different ions,
i.e. Ago, Ag+,
Ag2+ and Ag3+. Elemental silver has
no antibacterial activity and the principal active component is the Ag+ cation which
forms when in contact with
aqueous solutions. This ion has wide-ranging detrimental effects on the bacterial cell by disrupting membrane function and enzyme activity. There is activity against
a broad range of
bacterial pathogens including the important Staph.
aureus and Ps. aeruginosa. Since the silver
ion can be quenched by the presence
of chloride ions, continued
activity relies on the continuous release of further
silver ions. Improved activity has been reported for the use of
nanocrystalline silver
which also appears
to have an antiinflammatory action.
Despite its widespread use there are limited reports on the toxicity of silver and the incidence of resistance is currently low.
The worsening situation with regard
to antibiotic resistance
has brought all potential therapies into sharper focus and silver
is a candidate for increasing use, for example as a coating on medical devices
such as urinary catheters and endotracheal tubes
to prevent biofilm formation.
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