Efficacy of antimicrobial polymer coatings in an animal model of bacterial infection associated with foreign body implants.
OBJECTIVE
To assess support discs, comprising polyethylene terephthalate (PET), coated with different polymer/levofloxacin combinations for antimicrobial activity in an animal model of infection, in order to explore the use of specific polymer coatings incorporating levofloxacin as a means of reducing device-related infections.


METHODS
Aliphatic polyester-polyurethanes containing different ratios of poly(lactic acid) diol and poly(caprolactone) diol were prepared, blended with levofloxacin and then used to coat support discs. The in vitro levofloxacin release profiles from these discs were measured in aqueous solution. Mice were surgically implanted with the coated discs placed subcutaneously and infection was initiated by injection of 10(6) cfu of Staphylococcus aureus into the subcutaneous pocket containing the implant. After 5, 10, 20 and 30 days, the discs were removed, and the number of bacteria adhering to the implant and the residual antimicrobial activity of the discs were determined.


RESULTS
In vitro, the release of levofloxacin from the coated discs occurred at a constant rate and then reached a plateau at different timepoints, depending on the polymer preparation used. In vivo, none of the discs coated with polymer blends containing levofloxacin was colonized by S. aureus, whereas 94% of the discs coated with polymer alone were infected. All discs coated with levofloxacin-blended polymers displayed residual antimicrobial activity for at least 20 days post-implantation.


CONCLUSIONS
Bioerodable polyester-polyurethane polymer coatings containing levofloxacin can prevent bacterial colonization of implants in an intra-operative model of device-related infections.
Department of Microbiology and Immunology, The University of Melbourne, Parkville, Victoria 3010, Australia.
Emily
E
Hart
Kristy
K
Azzopardi
Heng
H
Taing
Florian
F
Graichen
Justine
J
Jeffery
Roshan
R
Mayadunne
Malsha
M
Wickramaratna
Mike
M
O'Shea
Brunda
B
Nijagal
Rebecca
R
Watkinson
Stephen
S
O'Leary
Barrie
B
Finnin
Russell
R
Tait
Roy
R
Robins-Browne
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D005260:Female; D005547:Foreign Bodies; D006801:Humans; D064704:Levofloxacin; D051379:Mice; D008807:Mice, Inbred BALB C; D015242:Ofloxacin / Q000494:pharmacology*; D011108:Polymers / Q000494:pharmacology*; D016459:Prosthesis-Related Infections / Q000517:prevention & control*; D013203:Staphylococcal Infections / Q000517:prevention & control*; D013211:Staphylococcus aureus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D011108:Polymers; D064704:Levofloxacin; D015242:Ofloxacin