1. volume 18 . number 12 . december 2009
Can heel raises improve calf muscle function?
Preventing chronic osteitis from developing into a Marjolin's ulcer
In vitro analysis of the efficacy of potential biofilm treatments
A review of current research on the role of bFGF and VEGF in angiogenesis
Pyoderma gangrenosum: a personal perspective
International wound organisations update

2. research
JOURNAL OF WOUND CARE VOL 18, NO 12, DECEMBER 2009508
Effects of biofilm treatments on
the multi-species Lubbock chronic
wound biofilm model
S.E. Dowd,1
PhD,
Director;
Y. Sun,2
PhD, Molecular
Microbiologist;
E. Smith,2
BSc,
LaboratoryTechnician;
J.P. Kennedy,3
RPh, PhD,
Assistant Professor,
Department of
Pharmaceutical Sciences;
C.E. Jones,3
Assistant
Professor, Department of
Pharmaceutical Sciences;
R.Wolcott,2
MD,
Medical Director;
1 US Department of
Agriculture ARS
Livestock Issues Research
Unit, Lubbock,Texas, USA;
2 Medical Biofilm
Research Institute,
Lubbock,Texas, USA;
continued over
F
inding and evaluating useful therapies
that can safely be used as adjunct topical
treatments for chronic wounds is becom-
ing increasingly important. In the USA,
chronic wounds impact on and reduce
the quality of life of millions of individuals, placing
a tremendous financial burden on these unfortu-
nate patients, their families and the health-care
system as a whole, while also contributing to the
deaths of hundreds of thousands.1-7
Both the scientific and clinical communities now
accept that multi-species biofilms are one of the uni-
versal impediments to the healing of chronic wound.6-
13
It is therefore a significant academic, commercial
and clinical goal to utilise this pathogenic paradigm
to find and evaluate new treatments that specifically
target biofilms in chronic wounds, thereby directly
addressing this universal impediment to healing.
Our group originally designed and described the
multi-species Lubbock chronic wound biofilm
(LCWB) model as a 24-hour laboratory assay that
can be used to screen potential therapeutic modali-
ties for their ability to inhibit the formation of
wound biofilms.14
Full details of the methodology
are given in the original paper.14
This model has the advantage of being rapid and
reproducible, and the effects of well-known thera-
peutics on biofilms very closely resembled those we
have observed clinically.
Several important multi-species models have been
designed to model oral biofilms.15-18
However, the
LCWB model was the first rapid-screening (24 hours)
model specifically designed to evaluate the qualita-
tive and quantitative efficacy of treatments on a
multi-species biofilm that can simulate the biobur-
den within chronic wounds.
In this paper, the LCWB model developed in our
laboratories is used to describe the effects of several
biofilm effectors on the population dynamics and
extent of growth.
! Objective: To evaluate the efficacy of several biofilm effectors in inhibiting biofilm formation in an in
vitro multi-species chronic wound biofilm model.
! Method: The Lubbock ChronicWound Biofilm (LCWB) model has been described in detail
elsewhere. Pathogens used in the model are Pseudomonas aeruginosa, Enterococcus faecalis and
Staphylococcus aureus. These are three of the most important species associated with biofilms. Here, the
model was exposed to the following biofilm effectors: xylitol, salicylic acid, farnesol, erythritol and two
! Results: Biofilm formation was completely inhibited in the LCWB model following treatment with
20% xylitol, 10% erythritol, 1,000µg/ml farnesol, 20mM salicylic acid or 0.1% of either of the two
consequently increasing the ratios of P. aeruginosa and E. faecalis within the biofilm. Xylitol had an
increasing inhibitory effect on P. aeruginosa (p<0.01) at all concentrations evaluated. Erythritol had an
inhibitory effect on P. aeruginosa and S. aureus growth (p<0.01) at over 5% concentrations.The inhibitory
effect on all LCWB species (p<0.01).
! Conclusion: The LCWB model provides a multi-species format with which to evaluate the effect of
biofilm effectors on wound flora in a biofilm phenotype.These results suggest that different treatments can
target specific populations within a biofilm.Salicylic acid preferentially targeted S.aureus,xylitol preferentially
targeted P.aeruginosa, while erythritol preferentially targeted both P.aeruginosa and S.aureus.In contrast,the
LipoGel® gel formulations. Salicylic acid specifi cally inhibited S. aureus (p<0.01) at 10mM and 20mM,
two LipoGel® gel formulations provided a broad, less preferential, inhibition of biofilm development.
proprietary, semi-solid, wound-dressing formulations currently under development (LipoGel® gels).
effect of both LipoGel® gel formulations was more broadly effective, with an increasingly inhibitory
biofilm-suppressing agents; multi-species chronic wound biofilm model
research
JOURNAL OF WOUND CARE VOL 18, NO 12, DECEMBER 2009512
Results
Objective measurements made by recording the dry
weight of the biofilm biomass are given in Table 1.
All of the treatments exhibited lower biomass for-
mation, based on the dry-weight measurements,
than the control biofilms.
These results were supported by the subjective
rankings, which indicated there was a visible reduc-
tion in the biofilm formation.
At critical concentrations, all of the treatment
effectors demonstrated visibly obvious and objec-
tively significant (p<0.01) inhibitory effects on bio-
film formation.
No visible biofilm (apparent 100% inhibition) was
evident following treatment with 20% xylitol, 10%
erythritol, 1,000µg/ml farnesol, 20mM salicylic acid
The qPCR assay results showed that Xylitol had a
selective inhibitory effect on P. aeruginosa (p<0.01)
at all concentrations, ranging from 2–20% (Table 1).
Erythritol inhibited P. aeruginosa and S. aureus
growth (p<0.01) at over 5% concentrations.
Discussion
The LCWB model was exposed to various concen-
trations of xylitol, erythritol, farnesol, salicylic acid
order to evaluate the responses of the bacterial pop-
ulation responses within the biofilm community.
Subjective visual observations and objective meas-
urements were made.
Erythritol and xylitol have been extensively stud-
ied as sugar substitutes and antibacterial agents,19
and are particularly noted for their ability to affect
Streptococcus spp. Xylitol was reported to inhibit
transfer of cariogenic bacteria, reduce bacterial
recolonisation20
and inhibit Streptococcus mutans
biofilm formation.21
Our results showed that far-
nesol had a remarkable inhibitory effect on P. aeru-
ginosa (p<0.01) at all three concentrations and
inhibited S. aureus growth at 1000µg/ml. Masako et
al. reported that xylitol and farnesol synergistically
inhibited S. aureus biofilm formation:22
xylitol inhib-
ited the formation of glycocalyx and farnesol-dis-
solved fibrin fibres. Our results support their finding
that 1000µg/ml farnesol inhibits S. aureus.
Salicylic acid has been verified to have notable
antibacterial activity. It reportedly inhibits adher-
ence, growth and biofilm formation of Staphylococcus
epidermidis.23
Sodium salicylate (5µM), a sodium salt
of salicyclic acid, given concomitantly with 1µg/ml
vancomycin, was reported to inhibit biofilm forma-
tion of S. epidermidis by 99.9%.24
Our results showed
that salicylic acid had a marked selective inhibition
of S. aureus (p<0.01) at 10 and 20mM when com-
pared with both P. aeruginosa and E. faecalis.
suppressing formulations that completely inhibited
biofilm formation at concentrations as low as 0.1%.
components chosen specifically to combat medical
biofilms by multiple mechanisms, including biofilm
dispersion and auto-inducer cell-signalling strate-
gies. Unlike typical wound gels, these systems are
not solubilised or dispersed in the presence of
wound exudate, thereby significantly extending
residence time in the wound bed.
To give some context to their potency, it is note-
worthy that these gels are typically used in wounds
at full strength (100%). However, under the condi-
tions reported here, the gels were capable of reduc-
ing the biofilm formation by approximately 45% or
more at very low concentrations (0.005–0.01%).
While some patterns of preferential inhibition
may be shown at ultra-low concentrations, the
potencies and concentrations used in practice sug-
gest these formulations will inhibit all species found
in this LCWB model.
Although one formulation was apparently more
potent than the other, the low concentrations tested
make it difficult to extrapolate a marked difference
between the two in practice.
Conclusion
Taken together, the effects of these effector treat-
ments illustrate the functionality of the LCWB as an
in vitro method for the study of the chronic wound
paradigm. This model provides a base for future test-
ing of additional host factors, antimicrobial, and
anti-biofilm treatments. "
YS developed the
methods, performed
most of the laboratory
studies, data compilation
and wrote the initial draft
of the manuscript.
SED was responsible for
the primary conception
of the project, project
management, data
interpretation, and
development and
approval of the final
version of the manuscript.
ES helpedYS perform all
of the laboratory
experiments and
compiling data.
DR helped with
conception of the project,
interpretation of the
results and the writing of
early drafts of the
manuscript.
RW was vital in
conception of the project
and approval of final draft
of the manuscript
12 James, G.A., Swogger,
E.,Wolcott, R. et al.
Biofilms in chronic
wounds.Wound Repair
Regen 2008; 16: 1, 37-44.
13 Gjodsbol, K.,
Christensen, J.J., Karlsmark,
T. et al. Multiple bacterial
species reside in chronic
wounds: a longitudinal
study. Int Wound J 2006; 3:
3, 225-231.
14 Sun,Y., Dowd, S.E.,
Smith, E. et al. In vitro
multispecies Lubbock
chronic wound biofilm
model.Wound Repair
Regen 2008; 16: 6, 805-813.
15 Keevil, C.W., Bradshaw,
D.J., Dowsett,A.B., Feary,T.
W. Microbial film
formation: dental plaque
deposition on acrylic tiles
using continuous culture
techniques. J Appl Bacteriol
1987; 62: 2, 129-138.
16 Bradshaw, D.J., Marsh, P.
D. Effect of sugar alcohols
on the composition and
metabolism of a mixed
culture of oral bacteria
grown in a chemostat.
Caries Res 1994; 28: 4,
251-256.
17 Bradshaw, D.J., Marsh, P.
D.,Allison, C., Schilling,
K.M. Effect of oxygen,
inoculum composition and
flow rate on development
of mixed-culture oral
biofilms. Microbiology
1996; 142 (Pt 3): 623-629.
18 Stoodley, P.,Wilson, S.,
Hall-Stoodley, L. et al.
Growth and detachment
of cell clusters from
mature mixed-species
biofilms.Appl Environ
Microbiol 2001; 67: 12,
5608-5613.
19 Makinen, K.K., Isotupa,
K.P., Kivilompolo,T. et al.
Comparison of erythritol
and xylitol saliva
stimulants in the control
of dental plaque and
mutans streptococci.
Caries Res 2001; 35: 2,
129-135.
20 Featherstone, J.D.
Delivery challenges for
fluoride, chlorhexidine and
xylitol. BMC Oral Health
2006;6 Suppl 1:S8.
21 Modesto,A., Drake,
D.R. Multiple exposures to
chlorhexidine and xylitol:
adhesion and biofilm
formation by Streptococcus
mutans. Curr Microbiol
2006; 52: 6, 418-423.
22 Katsuyama, M.,
KobayashiY, Ichikawa H, et
al.A novel method to
control the balance of skin
microflora Part 2.A study
to assess the effect of a
cream containing farnesol
and xylitol on atopic dry
skin. J Dermatol Sci 2005;
38: 3, 207-213.
23 Muller, E.,Al-Attar, J.,
Wolff,A.G., Farber, B.F.
Mechanism of salicylate-
mediated inhibition of
biofilm in Staphylococcus
epidermidis. J Infect Dis
1998; 177: 2, 501-503.
24 Polonio, R.E., Mermel,
L.A., Paquette, G.E., Sperry,
J.F. Eradication of biofilm-
forming Staphylococcus
epidermidis (RP62A) by a
combination of sodium
salicylate and vancomycin.
Antimicrob Agents
Chemother 2001; 45: 11,
3262-3266.
and two prototype LipoGel® gel formulations
in
Finally, both LipoGel® gels are novel biofilm-
LipoGel® gels are proprietary formulations with
or 0.1% of either LipoGel® gel (Table 1).
JOURNAL OF WOUND CARE VOL 18, NO 12, DECEMBER 2009508
S.E. Dowd,1
PhD,
Director;
Y. Sun,2
PhD, Molecular
Microbiologist;
E. Smith,2
BSc,
LaboratoryTechnician;
J.P. Kennedy,3
RPh, PhD,
Assistant Professor,
Department of
Pharmaceutical Sciences;
C.E. Jones,3
Assistant
Professor, Department of
Pharmaceutical Sciences;
R.Wolcott,2
MD,
Medical Director;
1 US Department of
Agriculture ARS
Livestock Issues Research
Unit, Lubbock,Texas, USA;
2 Medical Biofilm
Research Institute,
Lubbock,Texas, USA;
continued over
F
inding and evaluating useful therapies
that can safely be used as adjunct topical
treatments for chronic wounds is becom-
ing increasingly important. In the USA,
chronic wounds impact on and reduce
the quality of life of millions of individuals, placing
a tremendous financial burden on these unfortu-
nate patients, their families and the health-care
system as a whole, while also contributing to the
deaths of hundreds of thousands.1-7
Both the scientific and clinical communities now
accept that multi-species biofilms are one of the uni-
versal impediments to the healing of chronic wound.6-
13
It is therefore a significant academic, commercial
and clinical goal to utilise this pathogenic paradigm
to find and evaluate new treatments that specifically
target biofilms in chronic wounds, thereby directly
addressing this universal impediment to healing.
Our group originally designed and described the
multi-species Lubbock chronic wound biofilm
(LCWB) model as a 24-hour laboratory assay that
can be used to screen potential therapeutic modali-
ties for their ability to inhibit the formation of
wound biofilms.14
Full details of the methodology
are given in the original paper.14
This model has the advantage of being rapid and
reproducible, and the effects of well-known thera-
peutics on biofilms very closely resembled those we
have observed clinically.
Several important multi-species models have been
designed to model oral biofilms.15-18
However, the
LCWB model was the first rapid-screening (24 hours)
model specifically designed to evaluate the qualita-
tive and quantitative efficacy of treatments on a
multi-species biofilm that can simulate the biobur-
den within chronic wounds.
In this paper, the LCWB model developed in our
laboratories is used to describe the effects of several
biofilm effectors on the population dynamics and
extent of growth.
! Objective: To evaluate the efficacy of several biofilm effectors in inhibiting biofilm formation in an in
vitro multi-species chronic wound biofilm model.
! Method: The Lubbock ChronicWound Biofilm (LCWB) model has been described in detail
elsewhere. Pathogens used in the model are Pseudomonas aeruginosa, Enterococcus faecalis and
Staphylococcus aureus. These are three of the most important species associated with biofilms. Here, the
model was exposed to the following biofilm effectors: xylitol, salicylic acid, farnesol, erythritol and two
! Results: Biofilm formation was completely inhibited in the LCWB model following treatment with
20% xylitol, 10% erythritol, 1,000µg/ml farnesol, 20mM salicylic acid or 0.1% of either of the two
consequently increasing the ratios of P. aeruginosa and E. faecalis within the biofilm. Xylitol had an
increasing inhibitory effect on P. aeruginosa (p<0.01) at all concentrations evaluated. Erythritol had an
inhibitory effect on P. aeruginosa and S. aureus growth (p<0.01) at over 5% concentrations.The inhibitory
effect on all LCWB species (p<0.01).
! Conclusion: The LCWB model provides a multi-species format with which to evaluate the effect of
biofilm effectors on wound flora in a biofilm phenotype.These results suggest that different treatments can
target specific populations within a biofilm.Salicylic acid preferentially targeted S.aureus,xylitol preferentially
targeted P.aeruginosa, while erythritol preferentially targeted both P.aeruginosa and S.aureus.In contrast,the
LipoGel® gel formulations. Salicylic acid specifi cally inhibited S. aureus (p<0.01) at 10mM and 20mM,
two LipoGel® gel formulations provided a broad, less preferential, inhibition of biofilm development.
proprietary, semi-solid, wound-dressing formulations currently under development (LipoGel® gels).
effect of both LipoGel® gel formulations was more broadly effective, with an increasingly inhibitory
biofilm-suppressing agents; multi-species chronic wound biofilm model
research
Effects of biofilm treatments on
the multi-species Lubbock chronic
wound biofilm model
S.E. Dowd,1
PhD,
Director;
Y. Sun,2
PhD, Molecular
Microbiologist;
E. Smith,2
BSc,
LaboratoryTechnician;
J.P. Kennedy,3
RPh, PhD,
Assistant Professor,
Department of
Pharmaceutical Sciences;
C.E. Jones,3
Assistant
Professor, Department of
Pharmaceutical Sciences;
R.Wolcott,2
MD,
Medical Director;
1 US Department of
Agriculture ARS
Livestock Issues Research
Unit, Lubbock,Texas, USA;
2 Medical Biofilm
Research Institute,
Lubbock,Texas, USA;
continued over
F
inding and evaluating useful therapies
that can safely be used as adjunct topical
treatments for chronic wounds is becom-
ing increasingly important. In the USA,
chronic wounds impact on and reduce
the quality of life of millions of individuals, placing
a tremendous financial burden on these unfortu-
nate patients, their families and the health-care
system as a whole, while also contributing to the
deaths of hundreds of thousands.1-7
Both the scientific and clinical communities now
accept that multi-species biofilms are one of the uni-
versal impediments to the healing of chronic wound.6-
13
It is therefore a significant academic, commercial
and clinical goal to utilise this pathogenic paradigm
to find and evaluate new treatments that specifically
target biofilms in chronic wounds, thereby directly
addressing this universal impediment to healing.
Our group originally designed and described the
multi-species Lubbock chronic wound biofilm
(LCWB) model as a 24-hour laboratory assay that
can be used to screen potential therapeutic modali-
ties for their ability to inhibit the formation of
wound biofilms.14
Full details of the methodology
are given in the original paper.14
This model has the advantage of being rapid and
reproducible, and the effects of well-known thera-
peutics on biofilms very closely resembled those we
have observed clinically.
Several important multi-species models have been
designed to model oral biofilms.15-18
However, the
LCWB model was the first rapid-screening (24 hours)
model specifically designed to evaluate the qualita-
tive and quantitative efficacy of treatments on a
multi-species biofilm that can simulate the biobur-
den within chronic wounds.
In this paper, the LCWB model developed in our
laboratories is used to describe the effects of several
biofilm effectors on the population dynamics and
extent of growth.
! Objective: To evaluate the efficacy of several biofilm effectors in inhibiting biofilm formation in an in
vitro multi-species chronic wound biofilm model.
! Method: The Lubbock ChronicWound Biofilm (LCWB) model has been described in detail
elsewhere. Pathogens used in the model are Pseudomonas aeruginosa, Enterococcus faecalis and
Staphylococcus aureus. These are three of the most important species associated with biofilms. Here, the
model was exposed to the following biofilm effectors: xylitol, salicylic acid, farnesol, erythritol and two
! Results: Biofilm formation was completely inhibited in the LCWB model following treatment with
20% xylitol, 10% erythritol, 1,000µg/ml farnesol, 20mM salicylic acid or 0.1% of either of the two
consequently increasing the ratios of P. aeruginosa and E. faecalis within the biofilm. Xylitol had an
increasing inhibitory effect on P. aeruginosa (p<0.01) at all concentrations evaluated. Erythritol had an
inhibitory effect on P. aeruginosa and S. aureus growth (p<0.01) at over 5% concentrations.The inhibitory
effect on all LCWB species (p<0.01).
! Conclusion: The LCWB model provides a multi-species format with which to evaluate the effect of
biofilm effectors on wound flora in a biofilm phenotype.These results suggest that different treatments can
target specific populations within a biofilm.Salicylic acid preferentially targeted S.aureus,xylitol preferentially
targeted P.aeruginosa, while erythritol preferentially targeted both P.aeruginosa and S.aureus.In contrast,the
LipoGel® gel formulations. Salicylic acid specifi cally inhibited S. aureus (p<0.01) at 10mM and 20mM,
two LipoGel® gel formulations provided a broad, less preferential, inhibition of biofilm development.
proprietary, semi-solid, wound-dressing formulations currently under development (LipoGel® gels).
effect of both LipoGel® gel formulations was more broadly effective, with an increasingly inhibitory
biofilm-suppressing agents; multi-species chronic wound biofilm model
research
JOURNAL OF WOUND CARE VOL 18, NO 12, DECEMBER 2009508
Effects of biofilm treatments on
the multi-species Lubbock chronic
wound biofilm model
S.E. Dowd,1
PhD,
Director;
Y. Sun,2
PhD, Molecular
Microbiologist;
E. Smith,2
BSc,
LaboratoryTechnician;
J.P. Kennedy,3
RPh, PhD,
Assistant Professor,
Department of
Pharmaceutical Sciences;
C.E. Jones,3
Assistant
Professor, Department of
Pharmaceutical Sciences;
R.Wolcott,2
MD,
Medical Director;
1 US Department of
Agriculture ARS
Livestock Issues Research
Unit, Lubbock,Texas, USA;
2 Medical Biofilm
Research Institute,
Lubbock,Texas, USA;
continued over
F
inding and evaluating useful therapies
that can safely be used as adjunct topical
treatments for chronic wounds is becom-
ing increasingly important. In the USA,
chronic wounds impact on and reduce
the quality of life of millions of individuals, placing
a tremendous financial burden on these unfortu-
nate patients, their families and the health-care
system as a whole, while also contributing to the
deaths of hundreds of thousands.1-7
Both the scientific and clinical communities now
accept that multi-species biofilms are one of the uni-
versal impediments to the healing of chronic wound.6-
13
It is therefore a significant academic, commercial
and clinical goal to utilise this pathogenic paradigm
to find and evaluate new treatments that specifically
target biofilms in chronic wounds, thereby directly
addressing this universal impediment to healing.
Our group originally designed and described the
multi-species Lubbock chronic wound biofilm
(LCWB) model as a 24-hour laboratory assay that
can be used to screen potential therapeutic modali-
ties for their ability to inhibit the formation of
wound biofilms.14
Full details of the methodology
are given in the original paper.14
This model has the advantage of being rapid and
reproducible, and the effects of well-known thera-
peutics on biofilms very closely resembled those we
have observed clinically.
Several important multi-species models have been
designed to model oral biofilms.15-18
However, the
LCWB model was the first rapid-screening (24 hours)
model specifically designed to evaluate the qualita-
tive and quantitative efficacy of treatments on a
multi-species biofilm that can simulate the biobur-
den within chronic wounds.
In this paper, the LCWB model developed in our
laboratories is used to describe the effects of several
biofilm effectors on the population dynamics and
extent of growth.
! Objective: To evaluate the efficacy of several biofilm effectors in inhibiting biofilm formation in an in
vitro multi-species chronic wound biofilm model.
! Method: The Lubbock ChronicWound Biofilm (LCWB) model has been described in detail
elsewhere. Pathogens used in the model are Pseudomonas aeruginosa, Enterococcus faecalis and
Staphylococcus aureus. These are three of the most important species associated with biofilms. Here, the
model was exposed to the following biofilm effectors: xylitol, salicylic acid, farnesol, erythritol and two
! Results: Biofilm formation was completely inhibited in the LCWB model following treatment with
20% xylitol, 10% erythritol, 1,000µg/ml farnesol, 20mM salicylic acid or 0.1% of either of the two
consequently increasing the ratios of P. aeruginosa and E. faecalis within the biofilm. Xylitol had an
increasing inhibitory effect on P. aeruginosa (p<0.01) at all concentrations evaluated. Erythritol had an
inhibitory effect on P. aeruginosa and S. aureus growth (p<0.01) at over 5% concentrations.The inhibitory
effect on all LCWB species (p<0.01).
! Conclusion: The LCWB model provides a multi-species format with which to evaluate the effect of
biofilm effectors on wound flora in a biofilm phenotype.These results suggest that different treatments can
target specific populations within a biofilm.Salicylic acid preferentially targeted S.aureus,xylitol preferentially
targeted P.aeruginosa, while erythritol preferentially targeted both P.aeruginosa and S.aureus.In contrast,the
LipoGel® gel formulations. Salicylic acid specifi cally inhibited S. aureus (p<0.01) at 10mM and 20mM,
two LipoGel® gel formulations provided a broad, less preferential, inhibition of biofilm development.
proprietary, semi-solid, wound-dressing formulations currently under development (LipoGel® gels).
effect of both LipoGel® gel formulations was more broadly effective, with an increasingly inhibitory
biofilm-suppressing agents; multi-species chronic wound biofilm model
research
JOURNAL OF WOUND CARE VOL 18, NO 12, DECEMBER 2009508
Effects of biofilm treatments on
the multi-species Lubbock chronic
wound biofilm model
S.E. Dowd,1
PhD,
Director;
Y. Sun,2
PhD, Molecular
Microbiologist;
E. Smith,2
BSc,
LaboratoryTechnician;
J.P. Kennedy,3
RPh, PhD,
Assistant Professor,
Department of
Pharmaceutical Sciences;
C.E. Jones,3
Assistant
Professor, Department of
Pharmaceutical Sciences;
R.Wolcott,2
MD,
Medical Director;
1 US Department of
Agriculture ARS
Livestock Issues Research
Unit, Lubbock,Texas, USA;
2 Medical Biofilm
Research Institute,
Lubbock,Texas, USA;
continued over
F
inding and evaluating useful therapies
that can safely be used as adjunct topical
treatments for chronic wounds is becom-
ing increasingly important. In the USA,
chronic wounds impact on and reduce
the quality of life of millions of individuals, placing
a tremendous financial burden on these unfortu-
nate patients, their families and the health-care
system as a whole, while also contributing to the
deaths of hundreds of thousands.1-7
Both the scientific and clinical communities now
accept that multi-species biofilms are one of the uni-
versal impediments to the healing of chronic wound.6-
13
It is therefore a significant academic, commercial
and clinical goal to utilise this pathogenic paradigm
to find and evaluate new treatments that specifically
target biofilms in chronic wounds, thereby directly
addressing this universal impediment to healing.
Our group originally designed and described the
multi-species Lubbock chronic wound biofilm
(LCWB) model as a 24-hour laboratory assay that
can be used to screen potential therapeutic modali-
ties for their ability to inhibit the formation of
wound biofilms.14
Full details of the methodology
are given in the original paper.14
This model has the advantage of being rapid and
reproducible, and the effects of well-known thera-
peutics on biofilms very closely resembled those we
have observed clinically.
Several important multi-species models have been
designed to model oral biofilms.15-18
However, the
LCWB model was the first rapid-screening (24 hours)
model specifically designed to evaluate the qualita-
tive and quantitative efficacy of treatments on a
multi-species biofilm that can simulate the biobur-
den within chronic wounds.
In this paper, the LCWB model developed in our
laboratories is used to describe the effects of several
biofilm effectors on the population dynamics and
extent of growth.
! Objective: To evaluate the efficacy of several biofilm effectors in inhibiting biofilm formation in an in
vitro multi-species chronic wound biofilm model.
! Method: The Lubbock ChronicWound Biofilm (LCWB) model has been described in detail
elsewhere. Pathogens used in the model are Pseudomonas aeruginosa, Enterococcus faecalis and
Staphylococcus aureus. These are three of the most important species associated with biofilms. Here, the
model was exposed to the following biofilm effectors: xylitol, salicylic acid, farnesol, erythritol and two
! Results: Biofilm formation was completely inhibited in the LCWB model following treatment with
20% xylitol, 10% erythritol, 1,000µg/ml farnesol, 20mM salicylic acid or 0.1% of either of the two
consequently increasing the ratios of P. aeruginosa and E. faecalis within the biofilm. Xylitol had an
increasing inhibitory effect on P. aeruginosa (p<0.01) at all concentrations evaluated. Erythritol had an
inhibitory effect on P. aeruginosa and S. aureus growth (p<0.01) at over 5% concentrations.The inhibitory
effect on all LCWB species (p<0.01).
! Conclusion: The LCWB model provides a multi-species format with which to evaluate the effect of
biofilm effectors on wound flora in a biofilm phenotype.These results suggest that different treatments can
target specific populations within a biofilm.Salicylic acid preferentially targeted S.aureus,xylitol preferentially
targeted P.aeruginosa, while erythritol preferentially targeted both P.aeruginosa and S.aureus.In contrast,the
LipoGel® gel formulations. Salicylic acid specifi cally inhibited S. aureus (p<0.01) at 10mM and 20mM,
two LipoGel® gel formulations provided a broad, less preferential, inhibition of biofilm development.
proprietary, semi-solid, wound-dressing formulations currently under development (LipoGel® gels).
effect of both LipoGel® gel formulations was more broadly effective, with an increasingly inhibitory
biofilm-suppressing agents; multi-species chronic wound biofilm model
Abstract
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