Here - EWMA 2013

POSTER PRESENTATIONS
P 210
Poster: Basic Science
THE EFFECT OF NOVEL BIOFILM TECHNOLOGIES ON PLANKTONIC AND
BIOFILM FORMING MICROORGANISMS – IN VITRO
Louise Suleman 1 , Peter Clegg 1 , Christine Cochrane 1 , Jonathan Nosworthy 2
1 University of Liverpool (South Wirral, Cheshire, United Kingdom);
2 Advanced Medical Solutions Ltd (Winsford, Cheshire, United Kingdom).
Aim: Biofilms are thought to exist in at least 60% of chronic wounds and clear
associations have been made involving the presence of bacterial biofilms and delayed
wound healing. The aim of this study was to assess the effect of novel anti-biofilm
technologies and a commercially available, pre-blended antimicrobial, on the eradication
of bacterial and fungal biofilms.
Methods: P. aeruginosa*, S. aureus** and C. albicans*** were inoculated in Mueller
Hinton Broth (MHB) to 108 CFU/ml and biofilms were grown on pegs for 24 hours before
being treated with the commercial product, and compound A combined with either
compound B, compound C or compound D for 24 hours. The minimum inhibitory
concentration (MIC) and the minimum biofilm eradication concentration (MBEC) was
used to assess the effect of these treatments on planktonic and biofilm-forming
organisms by measuring the absorbance of the treatment plate at 620nm and growth on
Mueller Hinton Agar (MHA).
Results: MIC findings showed that growth was inhibited at various concentrations with
all compounds, with S. aureus and C. albicans showing greater sensitivity than P.
aeruginosa. All organisms were susceptible to the commercial product. MBEC results
revealed that higher concentrations of the commercial product and the compounds were
needed to eradicate biofilm growth.
Conclusions: This study indicates possible synergistic interactions between these
compounds in the inhibition or both planktonic and biofilm-forming organisms. Therefore
these compounds as a blended technology may be a viable option for the treatment of
both infected and biofilm-containing wounds.
*ATCC 9027
**ATCC 6538
***ATCC 10231
POSTER: BASIC SCIENCE
P 211
Poster: Basic Science
P. AERUGINOSA ISOLATED FROM CHRONIC WOUNDS SECRETE PROTEASES
THAT IMPAIR WOUND HEALING – AN IN VITRO STUDY
Louise Suleman 1 , Peter Clegg 1 , Christine Cochrane 1 Jonathan Nosworthy 2.
1 University of Liverpool (South Wirral, Cheshire, United Kingdom);
2 Advanced Medical Solutions Ltd (Winsford, Cheshire, United Kingdom).
Aim: Host proteases play vital roles in all stages of cutaneous wound repair and
although imbalances can lead to delayed wound repair; the role of bacterial proteases in
infected wounds have not been fully investigated. The aim of this study was to determine
the effect of bacterial proteases on wound closure and host protease production.
Methods: Staphylococcus aureus and Pseudomonas aeruginosa isolated from acute
and chronic equine wounds were grown in Dulbecco’s modified Eagle’s medium
(DMEM). Bacteria were removed using centrifugation and supernatants sterile filtered.
Fibroblasts isolated from chronic equine wounds were grown to 90% confluence before
creating a scratch in the monolayer. Control DMEM or bacterial-conditioned medium at
various dilutions were then added to the wounds and images taken at 0, 24 and 48
hours. Gelatin zymography was used to assess the release of proteases at using
medium taken at 0, 24 and 48 hours.
Results: P. aeruginosa isolated from chronic wounds significantly reduced wound
closure when compared to acute isolates and reference strains. Increasing dilutions of P.
aeruginosa-conditioned medium correlated with increased wound closure. Zymography
demonstrated the release of a 50kDa protease from P. aeruginosa isolated from chronic
wounds. The presence of this 50kDa protease was associated with the decrease of
fibroblast-derived gelatinases.
Conclusions: P. aeruginosa-derived 50kDa protease not only had a significant effect on
wound closure but also impacted upon the secretion of proteases from fibroblasts. These
findings highlight an important role for bacterial proteases in impaired wound healing and
also a possible route for therapeutic intervention.
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