Eradication of Wound Biofilms by Electrical Stimulation - Antibiofilm Agents: From Diagnosis to Treatment and Prevention - page 416

classical idea of antibiotic resistance. Resistance to antibiotics refers to planktonic
or biofilm cells that exhibit a transferable genetic mutation or acquire a plasmid or
transposon, conferring protection against antimicrobials (Lewis 2007 ). However,
multidrug tolerance observed in biofilms implies a transient, non-heritable pheno-
typic change proposed to be caused by numerous mechanisms: delayed penetration,
stress responses to unfavorable environmental conditions, development of persister
cells, and altered microenvironment (Gefen and Balaban 2009 ). These hypothe-
sized mechanisms enable biofilms to dodge the “magic” antibiotic bullet. Without
the aid of antimicrobials, clinicians are left with the physical removal of biofilms as
their primary recourse. In chronic wound infections, debridement is an essential
therapy, but it is not without a cost (Game 2008 ). The multiple forms of wound
debridement are riddled with problems including patient pain, collateral tissue
damage, and the length and cost of treatment (Falabella 2006 ). Consequently, the
physical sciences have been mined for alternatives to standard wound care (SWC).
One such promising physical science strategy is electrical stimulation which will be
the focus of this chapter.
1.3 Electrical Stimulation of Chronic Wounds
Electrotherapy is already utilized by physical therapists for a wide array of treat-
ments ranging from pain management, iontophoresis, and the stimulation of tissue
repair in chronic wounds (American Physical Therapy Association 2005 ). After
lengthy clinical trials and review, the use of electrical stimulation for tissue healing
and repair (ESTHR) was approved in the USA as an insured treatment of chronic
wounds in 2002 (Centers for Medicare and Medicaid Services 2002 ). However,
insurance companies will only cover ESTHR for wounds which have been treated
with SWC for 30 days and display no quantifiable improvements in wound healing.
There are three forms of ESTHR (Fig. 1 ) predominately utilized to treat chronic
wound infections: low-intensity direct current (LIDC), high-voltage pulsed current
(HVPC), and alternating current (AC). Devices that produce ESTHR are typically
made up of a component that produces the electricity and an anode and cathode,
which deliver the electrical therapy to the wound site. Regardless of the specified
form of electrotherapy, clinical trials have found that ESTHR is an effective
adjunctive therapy for treating wound infections. Due to the lack of standardization
amongst ESTHR devices, some healthcare providers remain skeptical. And
although many promising clinical studies have been performed with ESTHR, it
still remains unapproved as a wound healing therapy by the Food and Drug
Administration. The contraindications reported from ESTHR treatment include
enhanced pain to the patient (Sussman and BatesJensen 1998 ), potential disruption
of pacemakers to those with cardiac irregularities, electrophoretic effects on ions in
some medications (zinc, mercury, silver), and collateral tissue damage (Robinson
and Snyder-Mackler 2007 ).