Investigation of the in vitro antimicrobial activity of triclosan-coated suture materials on bacteria commonly isolated from wounds in dogs

To determine the in vitro effect of triclosan-coating of suture materials on the growth of clinically relevant bacteria, duration of the antimicrobial activity and effects on bacterial adherence.
Sample
Ten isolates each of methicillin susceptible S. pseudintermedius, methicillin resistant S. pseudintermedius, E. coli, AmpC and extended spectrum beta lactamase-producing E. coli from clinical wound infections.
Procedures
The isolates were plated onto Mueller-Hinton agar with three different types of triclosan-coated suture and their uncoated counterparts, and positive and negative controls. Zones of inhibition were recorded after overnight incubation. Sustained efficacy assays were also performed. Bacterial adherence was evaluated using scanning electron microscopy.
Results
Zones of inhibition were generated by the triclosan-coated suture material but not the uncoated sutures. Triclosan-coated suture materials demonstrated sustained inhibition (range 2-29 days) against all pathogens compared to the uncoated equivalents. Activity of the triclosan coated sutures was significantly greater against the Staphylococcal isolates compared to the E. coli isolates. Bacterial adherence was greatest to uncoated polyglactin-910 followed by triclosan-coated polyglactin-910, uncoated monofilament sutures, and least to coated monofilament sutures. Differing surface characteristics between the multi- and mono-filament suture materials may be equally, or more, important than triclosan coating, however the triclosan-coating does have an effect against bacterial adherence.
Conclusion and clinical relevance:
Triclosan-coated, particularly monofilament, sutures inhibit common veterinary pathogens in vitro, including multidrug resistant bacteria. This may help to reduce the risk of post-operative wound infections, but further studies are required to demonstrate clinical efficacy.