In vitro comparison of antimicrobial activity of iodine and silver dressings against biofilms.
OBJECTIVE
To compare the antimicrobial effectiveness of silver- and iodine-containing wound dressings against preformed mature biofilms of pathogenic wound bacteria grown in vitro.


METHODS
Biofilms of Pseudomonas aeruginosa and Staphylococcus aureus were grown within an in vitro flat bed perfusion biofilm model. Mature biofilms were removed and exposed to wound dressings containing either silver or iodine (Aquacel Ag and Iodozyme) within a static diffusion method, for up to 24 hours. This method was designed to reflect certain key features that determine antimicrobial activity within the wound. The numbers of viable bacteria surviving in the biofilms were determined at set time intervals over the test period.


RESULTS
Both test dressings exerted an antimicrobial effect against the target species biofilms, although the iodine dressing was more efficacious under the experimental conditions employed.


CONCLUSIONS
There are large and potentially significant differences (as measured in vitro) in the effectiveness of wound dressings containing broad-spectrum antimicrobial agents such as silver and iodine against specific types of bacterial biofilms.
Centre for Research in Biomedicine, School of Life Sciences, University of the West of England, Bristol, UK.
R M S
RM
Thorn
A J
AJ
Austin
J
J
Greenman
J P G
JP
Wilkins
P J
PJ
Davis
D000287:Administration, Topical; D000704:Analysis of Variance; D047070:Bandages, Hydrocolloid / Q000592:standards; D018441:Biofilms / Q000187:drug effects*; D002266:Carboxymethylcellulose Sodium / Q000627:therapeutic use*; D018929:Cell Culture Techniques; D015169:Colony Count, Microbial; D004353:Drug Evaluation, Preclinical; D006801:Humans; D017613:Iodine Compounds / Q000627:therapeutic use*; D016014:Linear Models; D011552:Pseudomonas Infections / Q000188:drug therapy; D018030:Silver Compounds / Q000627:therapeutic use*; D013203:Staphylococcal Infections / Q000188:drug therapy; D013997:Time Factors; D014946:Wound Infection / Q000188:drug therapy* / Q000382:microbiology
D017613:Iodine Compounds; D018030:Silver Compounds; D002266:Carboxymethylcellulose Sodium